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  • Chemistry  (3,659)
  • Polymer and Materials Science  (440)
  • Fluid Mechanics and Thermodynamics  (44)
  • 1945-1949  (3,703)
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  • 1
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    A Simplified Theory of Porous Wall Cooling (1947)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: The rate of heat transfer between a fluid stream in turbulent flow and a smooth, solid wall is largely controlled by the relatively high resistance of the laminar sublayer next to the wall. Although this laminar layer ii extremely thin, heat can be transferred through it only by molecular diffusion. Hence the resistance of this layer is very much greater than for a layer the same thickness farther out in the stream where turbulent exchange is the controlling factor. The thickness of the laminar layer is difficult to define precisely, since there is a gradual transition to the turbulent flow outside, but for the usual scale of many engineering applications almost half the temperature difference between the fluid and the wall occurs in a layer of a few thousands of an inch in thickness. When the wall is made of porous material and a coolant gas is forced through the wall into the stream, it has been found that a very small flow rate of the coolant is remarkably effective in keeping the wall at a low temperature. The coolant flow rate required is such as to give an average velocity normal cooling wall of the order of 1 per cent of the main stream velocity. This flow rate is so low that clearly the injected gas must act as an insulator rather than as a normal coolant. Because of its relatively low velocity, the injected gas can have very little influence on heat convection or momentum transfer in the turbulent stream, and its effect must be confined to the laminar sublayer. The possible influence of the coolant flow on the thickness of the laminar layer will be discussed in Section V.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: JPL-PR-4-50
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  • 2
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    Two-Dimensional Motion of a Gas at Large Supersonic Velocities (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A large number of papers have been devoted to the problem of integration of equations of two-dimensional steady nonvertical adiabatic motion of a gas. Most of these papers are based on the application of the hodograph method of S. A. Chaplygin in which the plane of the hodograph of the velocity is taken as the region of variation of the independent variables in the equations of motion; the equations become linear in this plane. The exact integration of these equations is, however, obtained in the form of infinite series containing hypergeometric functions. The obtaining of such solutions and their investigation involves extensive computations. As a result, methods have been developed for the approximate integration of the equations of motion first transformed to a linear form. S. A. Chaplygin first pointed out such an approximate method applicable to flows in which the Mach number does not exceed 0.4.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1239 , Prikladnaia Matematika I Mekhanika, Tom XI
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  • 3
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    A Class of De Laval Nozzles (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A study is made herein of the irrotational adiabatic motion of a gas in the transition from subsonic to supersonic velocities. A shape of the de Laval nozzle is given, which transforms a homogeneous plane-parallel flow at large subsonic velocity into a supersonic flow without any shockwaves beyond the transition line from the subsonic to the supersonic regions of flow. The method of solution is based on integration near the transition line of the gas equations of motion in the form investigated by S. A. Christianovich.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1236 , Prikladnaia Matematika I Mekhanika, Tom XI
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  • 4
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    The Characteristics Method Applied to Stationary Two-Dimensional and Rotationally Symmetrical Gas Flows (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: By means of characteristics theory, formulas for the numerical treatment of stationary compressible supersonic flows for the two-dimensional and rotationally symmetrical cases have been obtained from their differential equations.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1211 , ZWB Forschungsbericht; Rept-1581
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  • 5
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    The Turbulent Flow in Diffusers of Small Divergence Angle (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The turbulent flow in a conical diffuser represents the type of turbulent boundary layer with positive longitudinal pressure gradient. In contrast to the boundary layer problem, however, it is not necessary that the pressure distribution along the limits of the boundary layer(along the axis of the diffuser) be given, since this distribution can be obtained from the computation. This circumstance, together with the greater simplicity of the problem as a whole, provides a useful basis for the study of the extension of the results of semiempirical theories to the case of motion with a positive pressure gradient. In the first part of the paper,formulas are derived for the computation of the velocity and.pressure distributions in the turbulent flow along, and at right angles to, the axis of a diffuser of small cone angle. The problem is solved.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1137 , Central Aero-Hydrodynaical Institute Reports; Rept-462
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  • 6
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    Vibration Survey of Blades in 19XB Axial-Flow Compressor (1948)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Strain gages were used to measure blade vibrations possibly causing failure in the 10-stage compressor of the 19XB jet-propulsion engine. The seventh and tenth stages were of great concern as a result of failures experienced by the manufacturer. Strain-gage records were obtained from all stages during acceleration, deceleration, and constant speed runs. Curves are presented herein showing the maximum allowable vibratory stress for a given speed, the change of the damping coefficient with the mounting of a strain gage at the base of the blade, the effect of rotor speed, on blade natural frequency, and the effect of the order of first bending-mode vibration on stress. It was found that for all stages the lower the order of vibration the higher the stress but no destructive vibrations were detected.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SE8A28
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  • 7
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    Effect of Air-Flow Distribution and Total-Pressure Loss on Performance of One-Sixth Segment of Turbojet Combuster (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: An investigation has been conducted on a one-sixth segment of an annular turbojet combustor to determine the effects of modification in air-flow distribution and total-pressure loss on the performance of the segment. The performance features investigated during this series of determinations were the altitude operational limits and the temperature-rise efficiency. Altitude operational limits of the combustor segment, for the 19XB engine using the original combustor-basket design were approximately 38,000 feet at 17,000 rpm and 26,000 feet at 10,000 rpm. The altitude operational limits were approximately 50,000 feet at 17,000 rpm and 38,000 feet at 10,000 rpm for a combustor-basket design in which the air-passage area in the basket was redistributed so as to admit gradually no more than 20 percent of the air along the first half of the basket. In this case the total pressure loss through the combustor segment was not appreciably changed from the total-pressure loss for the original combustor basket design. Altitude operational limits of the combustor segment for the 19XB engine were above 52,000 feet at 17,000 rpm and were approximately 23,000 feet at 10,000 rpm for a combustor-basket design in which the distribution of the air-passage area in the basket was that of the original design but where the total-pressure loss was increased to 19 times the inlet reference kinetic pressure at an inlet-to-outlet density ratio of 2.4. The total-pressure loss for the original design was 14 times the inlet kinetic reference pressure at an inlet-to-outlet density ratio of 2.4.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SE7K16
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  • 8
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    Heat Transfer from High-Temperature Surfaces to Fluids III - Correlation of Heat-Transfer Data for Air Flowing in Silicon Carbide Tube with Rounded Entrance, Inside Diameter of 3/4 Inch, and Effective Length of 12 Inches (1949)
    In:  CASI
    Details
    Publication Date: 2019-08-13
    Description: A heat-transfer investigation was conducted with air flowing through an electrically heated silicon carbide tube with a rounded entrance, an inside diameter of 3/4 inch, and effective heat-transfer length of 12 inches over a range of Reynolds numbers up to 300,000 and a range of average inside-tube-wall temperatures up to 2500 R. The highest corresponding local outside-tube-wall temperature was 3010 R.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA/RM-E9D12
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  • 9
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    Behavior of the Laminar Boundary Layer for Periodically Oscillating Pressure Variation (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The calculation of the phenomena within the boundary layer of bodies immersed in a flow underwent a decisive development on the basis of L. Prandtl's trains of thought, stated more than forth years ago, and by numerous later treatises again and again touching upon them. The requirements of the steadily improving aerodynamics of airplanes have greatly increased with the passing of time and recently research became particularly interested in such phenomena in the boundary layer as are caused by small external disturbances. Experimental results suggest that, for instance, slight fluctuations in the free stream velocities as they occur in wind tunnels or slight wavelike deviations of outer wing contours from the prescribed smooth course as they originate due to construction inaccuracies may exert strong effects on the extent of the laminar boundary layer on the body and thus on the drag. The development of turbulence in the last part of the laminar portion of the boundary layer is, therefore, the main problem, the solution of which explains the behavior of the transition point of the boundary layer. A number of reports in literature deal with this problem,for instance, those of Tollmien, Schlichting, Dryden, and Pretsch. The following discussion of the behavior of the laminar boundary layer for periodically oscillating pressure variation also purports to make a contribution to that subject.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1228 , Ludwig Prandtl zum 70. Geburtstage, Schriften der Deutschen Akademie der Luftfahrtforschung, Publications of the Germany academy for Aviation Research; 247-255
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  • 10
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    Some Aerodynamic Relations for an Airfoil in Oblique Flow (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Some aerodynamic relations are derived which exist between two infinitely long airfoils if one is in a straight flow and the other in oblique flow, and both present the same profile in the direction of flow.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1158 , Deutsche Luftfahrtforschung, Forschungsbericht; Rept-1497
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  • 11
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    Laboratory Report on the Investigation of the Flow around Two Turbine-Blade Profiles using the Interferometer Method (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: At the request of the Junkers Aircraft and Engine Construction Company, Engine Division, Dessau Main Plant, an investigation was made using the interferometer method on the two turbine-blade profiles submitted. The interferometer method enables making visible the differences in density and consequently the boundary layers that develop when a flow is directed on the profile. Recognition of the points on the profile at which separation of flow occurs is thus possible. By means of the interference photographs the extent of the dead-water region may be ascertained. The size of the dead-water region provides evidence as to the quality of the flow and allows a qualitative estimate of the amount of the flow losses. Interference photographs thus provide means of judging the utility of profiles under specific operating conditions and provide suggestions for possible changes of profile contours that might help to improve flow relations. Conclusions may be drawn concerning the influence of the blade-spacing ratio, the inlet-air angle, and the connection between the curvature of the profile contour and the point of separation of the flow from the profile surface.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1171 , Deutsche Luftfahrtforschung, Untersuchungen und Mitteilungen; Rept-2096
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  • 12
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    Experimental and Theoretical Investigations of Cavitation in Water (1945)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The cavitation in nozzles on airfoils of various shape and on a sphere are experimentally investigated. The limits of cavitation and the extension of the zone of the bubbles in different stages of cavitation are photographically established. The pressure in the bubble area is constant and very low, jumping to high values at the end of the area. The analogy with the gas compression shock is adduced and discussed. The collapse of the bubbles under compression shock produces very high pressures internally, which must be contributory factors to corrosion. The pressure required for purely mechanical corrosion is also discussed.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1078 , Eidgenoessische Technische Hochschule
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  • 13
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    Rotationally Symmetric Potential Flows (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: This paper includes the following topics: 1) Characteristic differential equations; 2) Treatment of practical examples; 3) First example: Diffuser; and 4) Second Example: Nozzle.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1244 , Chapter 4, Technische Hoschschule Dresden, Archives No. 44; Rept-44/4
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  • 14
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    Compressible Flow Tables for Air (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: This paper contains a tabulation of functions of the Mach number which are frequently used in high-speed aerodynamics. The tables extend from M = 0 to M = 10.0 in increments of 0.01 and are based on the assumption that air is a perfect gas having a specific heat ratio of 1.400.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L7K26
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  • 15
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    NACA Conference on Turbojet-Engine Thrust Augmentation Research: A Compilation of the Papers Presented by NACA Staff Members (1948)
    In:  CASI
    Details
    Publication Date: 2019-08-14
    Description: The conference on Turbojet-Engine Thrust-Augmentation Research was organized by the NACA to present in summarized form the results of the latest experimental and analytical investigations conducted at the Lewis Flight Propulsion Laboratory on methods of augmenting the thrust of turbojet engines. The technical discussions are reproduced herewith in the same form in which they were presented. The original presentation in this record are considered as complementary to, rather than substitutes for, the committee's system of complete and formal reports.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA Conference on Turbojet-Engine Thrust - Augmentation Research; Oct 28, 1948; Cleveland, OH; United States
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  • 16
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    Analytical Treatment of Normal Condensation Shock (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The condensation of water vapor in an air consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1174 , Heeres-Versuchsstelle; 66/72
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  • 17
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    Report on Investigation of Developed Turbulence (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The recent experiments by Jakob and Erk, on the resistance of flowing water in smooth pipes, which are in good agreement with earlier measurements by Stenton and Pannell, have caused me to change my opinion that the empirical Blasius law (resistance proportional to the 7/4 power of the mean velocity) was applicable up to arbitrarily high Reynolds numbers. According to the new tests the exponent approaches 2 with increasing Reynolds number, where it remains an open question whether or not a specific finite limiting value of the resistance factor lambda is obtained at R = infinity. With the collapse of Blasius' law the requirements which produced the relation that the velocity in the proximity of the wall varied in proportion to the 7th root of the wall distance must also become void. However, it is found that the fundamental assumption that led to this relationship can be generalized so as to furnish a velocity distribution for any empirical resistance law. These fundamental assumptions can be so expressed that for the law of velocity distribution in proximity of the wall as well as for that of friction at the wall, a form can be found in which the pipe diameter no longer occurs, or in other words, that the processes in proximity of a wall are not dependent upon the distance of the opposite wall.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1231 , Zeitschrift fuer Angewandte Matematik und Mechanik; 5; 2; 136-139
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  • 18
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    Lift Force of an Arrow-Shaped Wing (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The flow about a conical body of an ideal compressible fluid is considered. Assume that the velocity of the oncoming flow at infinity W is directed along the z-axis. The system of Cartesian coordinates x, y, z with origin at the vertex of the cone O is shown. From the considerations,of the dimensional theory, it may be found that along any ray issuing from O the components of the velocity u, v, W+w along the coordinate axes will maintain a constant value. It is further assumed that the conical body has such shape and disposition relative to the flow that u, v, and w are small in comparison with W.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1245 , Prikladnaya Matematika I Mekhanika; X; 513-520
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  • 19
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    Gas Motion in a Local Supersonic Region and Conditions of Potential-Flow Breakdown (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: For a certain Mach number of the oncoming flow, the local velocity first reaches the value of the local velocity of sound (M = 1) at some point on the surface of the body located within the flow. This Mach number is designated the critical Mach number M(sub cr). By increasing the flow velocity, a supersonic local region is formed bounded by the body contour and the line of transition from subsonic to supersonic velocity. As is shown by observations with the Toepler apparatus, at a certain flow Mach number M 〉 M(sub cr) a shock wave is formed near the body that closes the local supersonic region from behind. The formation of the shock wave is associated with the appearance of an additional resistance defined as the wave drag. In this paper, certain features are described of the flow in the local supersonic region, which is bounded by the contour of the body and the transition line, and conditions are sought for which the potential flow with the local supersonic region becomes impossible and a shock wave occurs. In the first part of the paper, the general properties of the potential flow in the local supersonic region, bounded by the contour of the profile and the transition line, are established. It is found that at the transition line, if it is not a line of discontinuity, the law of monotonic variation of the angle of inclination of the velocity vector holds (monotonic law). An approximation is given for the change in velocity at the contour of the body. The flow about a contour having a straight part is studied. In the second part of the paper, an approximation is given of the magnitudes of the accelerations at the interior points of the supersonic region. With the aid of these approximations, it is shown that for profiles convex to the flow the breakdown of the potential flow,associated with an increase of the Mach number of the oncoming flow, cannot be due to the formation of an envelope of the characteristics within the supersonic region. On the basis of the monotonic law, the transitional Mach number M is found, beyond which the potential flow with local supersonic region becomes impossible.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1213 , Prikladnaya Matematika i Mekhanika; 10; 4; 481-502
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  • 20
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    On the Theory of the Laval Nozzle (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In the present paper, the motion of a gas in a plane-parallel Laval nozzle in the neighborhood of the transition from subsonic to supersonic velocities is studied. In a recently published paper, F. I. Frankl, applying the holograph method of Chaplygin, undertook a detailed investigation of the character of the flow near the line of transition from subsonic to supersonic velocities. From the results of Tricomi's investigation on the theory of differential equations of the mixed elliptic-hyperbolic type, Frankl introduced as one of the independent variables in place of the modulus of the velocity, a certain specially chosen function of this modulus. He thereby succeeded in explaining the character of the flow at the point of intersection of the transition line and the axis of symmetry (center of the nozzle) and in studying the behavior of the stream function in the neighborhood of this point by separating out the principal term having, together with its derivatives, the maximum value as compared with the corresponding corrections. This principal term is represented in Frankl's paper in the form of a linear combination of two hypergeometric functions. In order to find this linear combination, it is necessary to solve a number of boundary problems, which results in a complex analysis. In the investigation of the flow with which this paper is concerned, a second method is applied. This method is based on the transformation of the equations of motion to a form that may be called canonical for the system of differential equations of the mixed elliptic-hyperbolic type to which the system of equations of the motion of an ideal compressible fluid refers. By studying the behavior of the integrals of this system in the neighborhood of the parabolic line, the principal term of the solution is easily separated out in the form of a polynomial of the third degree. As a result, the computation of the transitional part of the nozzle is considerably simplified.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1212 , Prikladnaya Matematika I Mekhanika; 10; 4; 503-512
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  • 21
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    On the Problems of Chaplygin for Mixed Sub-and Supersonic Flows (1947)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: There are investigated the problems of the flow of a supersonic jet out of a vessel with plane side walls and the problem of the supersonic flow about a wedge when there is a zone of local subsonic velocities ahead of the wedge.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1155 , Bulletin de L'Academie des Sciences de L'URSS; 9; 121-143
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  • 22
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    Equations for Adiabatic but Rotational Steady Gas Flows without Friction (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: This paper makes the following assumptions: 1) The flowing gases are assumed to have uniform energy distribution. ("Isoenergetic gas flows," that is valid with the same constants for the the energy equation entire flow.) This is correct, for example, for gas flows issuing from a region of constant pressure, density, temperature, end velocity. This property is not destroyed by compression shocks because of the universal validity of the energy law. 2) The gas behaves adiabatically, not during the compression shock itself but both before and after the shock. However, the adiabatic equation (p/rho(sup kappa) = C) is not valid for the entire gas flow with the same constant C but rather with an appropriate individual constant for each portion of the gas. For steady flows, this means that the constant C of the adiabatic equation is a function of the stream function. Consequently, a gas that has been flowing "isentropically",that is, with the same constant C of the adiabatic equation throughout (for example, in origination from a region of constant density, temperature, and velocity) no longer remains isentropic after a compression shock if the compression shock is not extremely simple (wedge shaped in a two-dimensional flow or cone shaped in a rotationally symmetrical flow). The solution of nonisentropic flows is therefore an urgent necessity.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1187 , Rept-44/1
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  • 23
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    Contribution to the Problem of Flow at High Speed (1949)
    In:  CASI
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    Publication Date: 2019-07-11
    Description: The authors regret that due to the lack of time the investigations could not be carried out to a more finished form. Especially in the first part it was intended to include a few further applications and to use them in the general considerations of this part. In spite of the fact that the intentions of the authors could not be realized, the authors felt that it would serve the aims of the competition to present part I in its present fragmentary form. The topics include: 1) A Few General Remarks Covering the Prandtl-Busemann Method; and 2) Effect of Compressibility in Axially Symmetrical Flow around an Ellipsoid.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1233 , Lilienthal-Gesellschaft fuer Luftfahrtforschung Bericht S 13/1, Part 1; 40-68; Rept-13/1
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  • 24
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    Heat Transmission in the Boundary Layer (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: In the present paper which deals with the heat transfer between the gas and the wall for large temperature drops and large velocities use is made of the method of Dorodnitsyn of the introduction of a new independent variable, with this difference, however, that the relation between the temperature field (that is, density) and the velocity field in the general case considered is not assumed given but is determined from the solution of the problem. The effect of the compressibility arising from the heat transfer is thus taken into account (at the same time as the effect of the compressibility at the large velocities). A method is given for determining the coefficients of heat transfer and the friction coefficients required in many technical problems for a curved wall in a gas flow at large Mach numbers and temperature drops. The method proposed is applicable both for Prandtl number P = 1 and for P not equal to 1.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1229 , Prikladnaya Matematika I Mekhanika, Tom X; 449-474
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  • 25
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    Theoretical Analysis of Stationary Potential Flows and Boundary Layers at High Speed (1948)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The present report consists of two parts. The first part deals with the two-dimensional stationary flow in the presence of local supersonic zones. A numerical method of integration of the equation of gas dynamics is developed. Proceeding from solutions at great distance from the body the flow pattern is calculated step by step. Accordingly the related body form is obtained at the end of the calculation. The second part treats the relationship between the displacement thickness of laminar and turbulent boundary layers and the pressure distribution at high speeds. The stability of the boundary layer is investigated, resulting in basic differences in the behavior of subsonic and supersonic flows. Lastly, the decisive importance of the boundary layer for the pressure distribution, particularly for thin profiles, is demonstrated.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1189 , Lilienthal-Gesellschaft fuer Luftfahrtforschung Bericht S13/1 Teil; 7-24
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  • 26
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    Flow Measurement by Means of Light Interference (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: There has been under development for the high-speed wind tunnel of the LFA an optical measuring arrangement for the qualitative and quantitative investigation of flow. By the use of interference measurements, the determination of density at the surface of the bodies being tested in the air stream and in the vicinity of these bodies can be undertaken. The results obtained so far in the simple preliminary investigations show that it is possible, even at a low Reynolds number, to obtain the density field in the neighborhood of a test body by optical means. Simple analytical expressions give the relation between density, pressure, velocity, and temperature. In addition to this, the interference measurement furnishes valuable data on the state of the boundary layer, that is, the sort of boundary layer (whether laminar or turbulent), as well as the temperature and velocity distribution.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1253 , Forschungsbericht; Rept-1167
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  • 27
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    Compression Shocks of Detached Flow (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: It is known that compression shocks which lead from supersonic to subsonic velocity cause the flow to separate on impact on a rigid wall. Such shocks appear at bodies with circular symmetry or wing profiles on locally exceeding sonic velocity, and in Laval nozzles with too high a back pressure. The form of the compression shocks observed therein is investigated.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1150 , Deutsche Luftfahrtforschung; Rept-1850
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  • 28
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    General Characteristics of the Flow through Nozzles at Near Critical Speeds (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The characteristics of the position and form of the transition surface through the critical velocity are computed for flow through flat and round nozzles from subsonic to supersonic velocity. Corresponding considerations were carried out for the flow about profiles in the vicinity of sonic velocity.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1147 , Deutsche Luftfahrtforchung; Rept-1992
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  • 29
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    Boundary Layer Theory (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part. These actual flows show a special characteristic, denoted as turbulence. The character of a turbulent flow is most easily understood the case of the pipe flow. Consider the flow through a straight pipe of circular cross section and with a smooth wall. For laminar flow each fluid particle moves with uniform velocity along a rectilinear path. Because of viscosity, the velocity of the particles near the wall is smaller than that of the particles at the center. i% order to maintain the motion, a pressure decrease is required which, for laminar flow, is proportional to the first power of the mean flow velocity. Actually, however, one ob~erves that, for larger Reynolds numbers, the pressure drop increases almost with the square of the velocity and is very much larger then that given by the Hagen Poiseuille law. One may conclude that the actual flow is very different from that of the Poiseuille flow.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1218
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  • 30
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    Two-Dimensional Potential Flows (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Contents include the following: Characteristic differential equations - initial and boundary conditions. Integration of the second characteristic differential equations. Direct application of Meyer's characteristic hodograph table for construction of two-dimensional potential flows. Prandtl-Busemann method. Development of the pressure variation for small deflection angles. Numerical table: relation between deflection, pressure, velocity, mach number and mach angle for isentropic changes of state according to Prandtl-Meyer for air (k = 1.405). References.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1243 , Chapter 3,Technische Hochschule Dresden, Archives No. 44/3; Rept-44/3
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  • 31
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    Effects of Compressibility on the Flow Past Thick Airfoil Sections (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Six, 3-inch-chord symmetrical airfoil sections having systematic variations in thickness and thickness location were tested at Mach numbers near flight values for propeller-shank sections. The tests, the results of which are presented in the form of schlieren photographs of the flow past each model and pressure-distribution charts for two of the model, were performed to illustrate the effects of compressibility on the flow past thick symmetrical airfoil sections. Representative flow photographs indicated that at Mach numbers approximately 0.05 above the critical Mach number a speed region was reached in which the flow oscillated rapidly and the separation point and the location of the shock wave were unstable. Fixing the transition on both surfaces of the airfoil was effective in reducing these rapid oscillations. The pressure distributions showed that the section normal-force coefficients for thick airfoils were very erratic at subcritical speeds; at supercritical speeds the section normal-force coefficients for the thick airfoils became more regular. Drag coefficients showed that considerable drag decreases can be expected by decreasing the model thickness ratio.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L6J17a
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  • 32
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    Heat Transfer from High-Temperature Surfaces to Fluids. III - Correlation of Heat-Transfer Data for Air Flowing in Silicon Carbide Tube with Rounded Entrance, Inside Diameter of 3/4 Inch, and Effective Length of 12 Inches (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A heat-transfer investigation was conducted with air flowing through an electrically heated silicon carbide tube with a rounded entrance, an inside diameter of 3/4 inch, and an effective heat-transfer length of 12 inches over a range of Reynolds numbers up to 300,000 and a range of average inside-tube-wall temperature up to 2500 R. The highest corresponding local outside-tube-wall temperature was 3010 R. Correlation of the heat-transfer data using the conventional Nueselt relation wherein physical properties of the fluid were evaluated at average bulk temperature resulted in a separation of data with tube-wall-temperature level. A satisfactory correlation of the heat-transfer data was obtained, however, by the use of modified correlation parameters wherein the mass velocity G (or product of average air density and velocity evaluated at bulk temperature P(sub b)V(sub b)) in the Reynolds number was replaced by the product of average air velocity evaluated at the bulk temperature and density evaluated at either the average inside-tube-wall temperature or the average film temperature; in addition, all the physical properties of air were correspondingly evaluated at either the average inside-tube-wall temperature or the average film temperature.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-E9D12-Pt-3 , Rept-1115-Pt-3
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  • 33
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    Lecture Series "Boundary Layer Theory". Part I - Laminar Flows (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: In the lecture series starting today author want to give a survey of a field of aerodynamics which has for a number of years been attracting an ever growing interest. The subject is the theory of flows with friction, and, within that field, particularly the theory of friction layers, or boundary layers. A great many considerations of aerodynamics are based on the ideal fluid, that is the frictionless incompressibility and fluid. By neglect of compressibility and friction the extensive mathematical theory of the ideal fluid, (potential theory) has been made possible. Actual liquids and gases satisfy the condition of incomressibility rather well if the velocities are not extremely high or, more accurately, if they are small in comparison with sonic velocity. For air, for instance, the change in volume due to compressibility amounts to about 1 percent for a velocity of 60 meters per second. The hypothesis of absence of friction is not satisfied by any actual fluid; however, it is true that most technically important fluids, for instance air and water, have a very small friction coefficient and therefore behave in many cases almost like the ideal frictionless fluid. Many flow phenomena, in particular most cases of lift, can be treated satisfactorily, - that is, the calculations are in good agreement with the test results, -under the assumption of frictionless fluid. However, the calculations with frictionless flow show a very serious deficiency; namely, the fact, known as d'Alembert's paradox, that in frictionless flow each body has zero drag whereas in actual flow each body experiences a drag of greater or smaller magnitude. For a long time the theory has been unable to bridge this gap between the theory of frictionless flow and the experimental findings about actual flow. The cause of this fundamental discrepancy is the viscosity which is neglected in the theory of ideal fluid; however, in spite of its extraordinary smallness it is decisive for the course of the flow phenomena.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1217
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  • 34
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    Tests of a Full-Scale Model of the Republic XF-91 Airplane in the Ames 40- by 80-Foot Wind Tunnel. Force and Moment Data (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Wind-tunnel tests of a full-scale model of the Republic XF-91 airplane having swept-back wings and a vee tail were conducted to determine both the stability and control characteristics of the model longitudinally, laterally, and directionally. Configurations of the model were investigated involving such variables as external fuel tanks, a landing gear, trailing-edge flaps, leading-edge slats, and a range of wing incidences and tail incidences.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SA9C04
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  • 35
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    Nonstationary Gas Flow in Thin Pipes of Variable Cross Section (1948)
    In:  CASI
    Details
    Publication Date: 2019-08-16
    Description: Characteristic methods for nonstationary flows have been published only for the special case of the isentropic flow up until the present, althought they are applicable in various places to more difficult questions too. This report derives the characteristic method for the flows which depend only on the position coordinates and time. At the same time the treatment of compression shocks is shown.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1196 , Zentrale fuer Wissenschaftliches Berichtswesen der Luftfahrtforschung des Generalluftzeugmeisters (ZWB); 1744
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  • 36
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    Investigation of Flow in a Centrifugal Pump (1946)
    In:  CASI
    Details
    Publication Date: 2019-08-16
    Description: The investigation of the flow in a centrifugal pump indicated that the flow patterns in frictional fluid are fundamentally different from those in frictionless fluid. In particular, the dead air space adhering to the section side undoubtedly causes a reduction of the theoretically possible delivery head. The velocity distribution over a parallel circle is also subjected to a noticeable change as a result of the incomplete filling of the passages. The relative velocity on the pressure side of the vane, which for passages completely filled with active flow would differ little from zero even at comparatively lower than normal delivery volume, is increased, so that no rapid reverse flow occurs on the pressure side of the vane even for smaller delivery volume. It was established, further, that the flow ceases to be stationary for very small quantities of water. The inflow to the impeller can be regarded as radial for the operating range an question. The velocity triangles at the exit are subjected to a significant alteration in shape ae a result of the increased peripheral velocity, which may be of particular importance in the determination of the guide vane entrance angle.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1089 , Mitteilungen des Hydraulischen Instituts der Technischen Hochschule; 4; 1-27
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  • 37
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    Calculation of Turbulent Expansion Processes (1945)
    In:  CASI
    Details
    Publication Date: 2019-08-15
    Description: On the basis of certain formulas recently established by L. Prandtl for the turbulent interchange of momentum in stationary flows, various cases of "free turbulence" - that is, of flows without boundary walls - are treated in the present report. Prandtl puts the apparent shearing stress introduced by the turbulent momentum interchange. This present report deals first with the mixing of an air stream of uniform velocity with the adjacent still air, than with the expansion or diffusion of an air jet in the surrounding air space.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1085 , Zeitschrift fuer angewandte Mathematik und Mechanik; 6; 1-12
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  • 38
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    Pressure Distribution Measurements on a Turbine Rotor Blade Passing Behind a Turbine Nozzle Lattice (1947)
    In:  CASI
    Details
    Publication Date: 2019-08-15
    Description: As a turbine rotor turns, the blades traverse the wake zones of the nozzle vanes. A periodic fluctuation of the pressure distribution around the circumference of the rotor blade is therefore caused. It was desired to investigate quantitatively this effect. At the same time, the magnitude of the force acting upon one profile of the rotor-blade lattice at various positions of this lattice relative to the nozzle lattice was to be determined.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1173 , Reports of the Lattice Conference: Berichte der Gittertagung; Mar 27, 1944 - Mar 27, 1944; Brunswick,; Germany|Berichte der Gittertagung; 95-100; M325/44g
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  • 39
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    An Analytical Investigation of the Heat Losses from a U.S. Navy K-Type Airship (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: The heat losses from the envelope surface of a U.S. Navy K-type airship are evaluated to determine if the use of heat is a feasible means of preventing ice and snow accumulations on lighter-than-air craft during flight and when moored uncovered. Consideration is given to heat losses in clear air (no liquid water present in the atmosphere) and in probable conditions of icing and snow. The results of the analysis indicate that the amount of heat required in flight to raise the surface temperature of the entire envelope to the extent considered adequate for ice protection, based on experience with tests of heavier-than-air craft, is very large. Existing types of heating equipment which could be used to supply this quantity of heat would probably be too bulky and heavy to provide a practical flight installation. The heat requirements to provide protection for the nose and stern regions in assumed mild to moderate icing conditions appear to be within the range of the capacity of current types of heating equipment suitable for flight use. The amount of heat necessary to prevent snow accumulations on the upper surface of the airship envelope when moored uncovered under all conditions appear to be excessive for the heating equipment presently available for flight use, but could possibly be achieved with auxiliary ground heating equipment.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SA6L20
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  • 40
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    Tests of Cascades of Airfoils for Retarded Flow (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Test results are present for cascades of airfoils in retarded flow and increasing pressure as corresponds to the case of the impeller of an axial propeller pump and propeller fan.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1190 , Transactions of the Society of Mechanical Engineers; 3; 13; 334-344
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  • 41
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    Investigation of Turbulent Mixing Processes (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: With water as driving medium and delivered medium in a device similar to a simple jet apparatus, the pressure and velocity fields of the mixing zone were explored with a pitot bar; the ratio of delivered to driving volume ranged between the values 0, 1, 2, and 4. An attempt was also made to analyze the mixing flow mathematically by integration of the equation of motion, with the aid of conventional formulas for the turbulent shearing stress, but this succeeded only approximately for the very simplified case that a driving jet is introduced in an unlimited parallel flow, while the pressure over the whole mixing field is assumed to be constant. In spite of these dissimilar assumptions for the theory and the experiment, the form of the measured and the computed velocity profiles indicates a very high degree of approximation. The pressure rise, which was approximated by Flugel's formulas, disclosed good agreement with the measured values.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1096 , Forschung auf dem Gebiete des Ingenieurwesens; 12; 1; 16-30
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  • 42
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    On Combustion in a Turbulent Flow (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The characteristics introduced by the turbulence in the process of the flame propagation are considered. On the basis of geometrical and dimensional considerations an expression is obtained for the velocity of the flame propagation in a flow of large scale of turbulence.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1110 , Journal of Technical Physics; 13; 10-Sep
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  • 43
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    Flow Investigation with the Aid of the Ultramicroscope (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: On the basis of photographic pictures the laminar flow at a pipe inlet was measured and compared with other measurements and computational results. The test setup is described in detail, and a series of the pictures obtained for turbulent flow is given.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1109 , Forschung auf dem Gebiete des Ingenieurwesens; 8; Pt 1; 42-47
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  • 44
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    The Effect of Turbulence on the Flame Velocity in Gas Mixtures (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The present report deals with the effect of turbulence on the propagation of the flame. Being based upon experiments with laminar as well as turbulent Bunsen flames, both the physico-chemical and the hydro-dynamical aspects of the problem are analyzed. A number of new deductions, interesting from the point of view of engine combustion and other very rapidly changing flame reactions, are made.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1112 , Zeitschrift fuer Elektrochemie und Angewandte Physikalische Chemiw; 46; 11; 601-626
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  • 45
    Electronic Resource
    Electronic Resource
    Preparation, purification, and polymerization of diethyl silicon dichloridePortion of thesis by Francis J. Honn for the degree of Master of Science, Polytechnic Institute of Brooklyn, 1946. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 102-120 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diethyl silicon dichloride was prepared by a Grignard synthesis and purified highly. The material in various stages of purification was hydrolyzed and then polymerized. The properties of the hydrolyzate and of the final polymer depended markedly upon the degree of purification of the dichloride. The reaction of diethylsilicanediol with phosphorous pentoxide was also studied; the predominating reaction appears to involve entrance of the pentoxide into the polymeric structure, rather than a simple acceleration of the polycondensation reaction by the removal of water.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010205
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  • 46
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    Polymerization of olefins and diolefins in suspension and emulsion. Part I. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 127-145 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This and a following article review the literature from 1910-1945 on polymerization of olefins and diolefins in suspension and emulsion, and present a number of new measurements not published to date. The subject is considered mainly from the point of view of scientific information on the mechanism of polymerization in aqueous suspensions and emulsions, but brief mention is also made of the more important disclosures in the patent literature. The new data presented in this article refer to (1) initial rates of polymerization of styrene, methyl methacrylate, vinyl acetate and acrylonitrile in aqueous suspensions and in soap emulsions as a function of catalyst concentration, temperature, and soap concentration; (2) influence of water-soluble activators, such as sodium bisulfite; (3) influence of initial size of monomer droplets on initial rates of monomer consumption; (4) study, with the aid of the electron microscope, of size of monomer droplets and polymer particles throughout polymerization; and (5) a few experiments on side reactions in the domain of higher conversions. No attempt is made in this paper to review and appraise the very large number of recent patents (from about 1930 on), which protect special procedures on the use of various promoting, regulating, or modifying ingredients. A complete digest of this practice does not exist at present, but reference may be made to the excellent chapter on emulsion polymerization in the book of Talalay and Magat (55), to the very valuable compilation of patents by Hosch in “India Rubber World” (27), and to the enumeration of a selected number of patents in the book of Scheiber (50) on pages 210-213.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010207
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  • 47
    Electronic Resource
    Electronic Resource
    Elastic properties of textile yarns, represented with the aid of a mechanical model (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 329-339 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of experiments on the elastic behavior of various textile materials was carried out. All results are described with the aid of a mechanical model. For this purpose it is necessary to introduce the possibility of a blockade of a part of the model. The elastic properties are characterized by the values of seven independent fundamental constants of the model. The value of one of these constants associated with the blockade can be determined experimentally in a direct way; it is found to be independent of the moisture content. The most important properties of the model correspond with the molecular image of Hermans.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010501
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  • 48
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    Preparation and properties of rubberlike high polymers. II. Polymerization of mixtures in bulkCommunication No. 54 from the Rubber Foundation. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 353-363 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mixtures of butadiene and dimethylbutadiene with varying quantities of styrene and acrylonitrile have been copolymerized under various catalytic conditions at 100°C. The formation of cyclic dimers from dienes and vinyl compounds is, in some cases, much more pronounced than the dimerization of the dienes alone. Since the latter is also a kind of Diels-Alder reaction, a series with increasing dienophilic properties can be established from a comparison of the yields of cyclic dimers. From solubility and swelling experiments it is evident that the polymers prepared from butadiene and the vinyl compounds and those from dimethylbutadiene and acrylonitrile are true copolymers. The mechanical properties of the copolymers from butadiene and increasing amounts of a vinyl compound change gradually from those of a rubber to those of the polyvinyl compound. The copolymers from a mixture containing 30% styrene or acrylonitrile are very similar, respectively, to Buna S and Perbunan. Copolymers of the same composition from dimethylbutadiene and acrylonitrile, on the other hand, form a new class of thermoplastics with a much higher temperature of elasticity.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010503
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  • 49
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    Preparation and properties of rubberlike high polymers. III. Polymerization of mixtures in emulsionCommunication No. 53 from the Rubber Foundation. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 364-379 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The copolymerization in emulsion of butadiene with varying amounts of styrene and acrylonitrile and of dimethylbutadiene with the latter vinyl compound has been studied on a laboratory scale. An essential difference between polymeric vinyl compounds and polydienes is the olefinic character of the latter, which leads to typical secondary changes in the polymers originally formed during the completion of the reaction. Such changes are of fundamental importance for the ultimate mechanical properties of polymers and copolymers based on dienes. After a brief discussion of the general theoretical line of thought serving as a base for our experiments, the influence of various factors on the rate of polymerization is pointed out and demonstrated by experiments. The changes in the nitrogen content of copolymers from acrylonitrile and the yields as a function of the reaction time have also been studied. From an investigation of some physical properties, such as solubility and swelling, the existence of true copolymers (of unknown irregularity) has been established. Copolymers from dimethylbutadiene and acrylonitrile represent a new class of olefinic thermoplastics resembling gutta-percha. Abbreviations used are BP (benzoyl peroxide) and DAB (diazoaminobenzene).
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010504
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  • 50
    Electronic Resource
    Electronic Resource
    Dependence of the average transversal on the longitudinal dimensions of statistical coils formed by chain molecules (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 380-388 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The transversal dimension of the statistical coil formed by a long-chain molecule in solution or in bulk rubber is independent of the longitudinal dimension, h1, of the coil as long as h1 is small compared with the length of the stretched molecule. On the other hand, the lateral dimension of a coil whose longitudinal vector, h1, is oriented in the direction of stretch undergoes a forced contraction during the deformation of bulk rubber. The forced contraction of the transversal dimension is therefore supplying an extra contribution to the entropy change. Its amount has been estimated in earlier work and it influences the numerical factor occurring in the formula connecting the strain-stretch relation for rubber with the molecular weight of the net fragments.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010505
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    The reaction of benzoyl peroxide with cyclohexane and cyclohexene. Contribution to the mechanism of the catalyzing action of peroxides in the polymerization of vinyl derivatives (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 407-418 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The course of the reactions of benzoyl peroxide with cyclohexane and cyclohexene may be accounted for by a mechanism involving free radicals and radical chain reactions. With cyclohexane, the average length of the chain hardly exceeds one step and one mole of hydrocarbon reacts with one mole of peroxide. With cyclohexene, chains of two and three steps also occur and about two and one-half moles of hydrocarbon per mole of peroxide take part in the reaction. It is shown that this is due to the one-sided addition of the primary radicals (originating from the peroxide) to the double bond, yielding a new radical without a double bond which can in turn react in the same way with another unsaturated molecule, thus giving rise to polycyclic compounds (chain formation). This polymerization reaction is, however, soon halted by a competitive side reaction involving substitution of the α- (or β)-methylene group, which leaves the double bond intact. In polymerizable vinyl derivatives in which no reactive α-methylene group is present, the competitive reaction cannot occur and the radical chain reaction continues to form a growing chain of interlinked monomeric molecules with annihilation of the double bonds. The two terminal groups of the macromolecules of the final polymerizate are radicals originating from the peroxide used as a catalyst. If a solvent is used, radicals of the latter may also appear occasionally as terminal groups of the polymer. The mechanism of the catalytic action of diacyl peroxides in the polymerization of vinyl derivatives is thus clarified. The molecule linking reaction induced by free radicals in unsaturated compounds also provides an explanation of the action of benzoyl peroxide as a rubber vulcanizer; the peroxide radicals are found as substituents in the rubber molecule.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010508
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    The Baker-Philippoff equation for cellulose acetate solutions (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 434-436 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By suitable alteration of the exponent the fit of viscosity-concentration data by a Philippoff type equation may be substantially improved. For a series of cellulose acetate solutions the exponent of best fit appears to be related to the physical properties and chemical type of the solvent.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010511
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    Advancing fronts in chemistry. Volume I. High polymers. Edited by Sumner B. Twiss, Department of Chemistry, Wayne University, Detroit, Michigan. Reinhold, New York, 1945. 196 pp. 15 × 23 cm. Price $4.00 (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 440-440 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010513
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  • 54
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    Spectrophotometric determination of the styrene content of butadiene-styrene copolymers (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 175-182 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ultraviolet absorption of polystyrene, with maximum absorption at 262 mμ, is due to the presence of phenyl residues in the polymer. The specific extinction coefficient is constant, i.e., independent of the molecular weight of the polymer. This shows that the extinction of the phenyl residues is additive. On the basis of this fact, it is shown that the styrene content of a butadiene-styrene copolymer (such as GR-S rubber) can be determined by ultraviolet spectrophotometry. The relative precision of the determination is about 1%, the probable relative accuracy is about 3%.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010305
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    Density of cellulose fibers. III. Density and refractivity of natural fibers and rayonCommunication No. 29 from the Laboratory for Cellulose Research. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 162-171 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A micromethod is described for density determinations of artificial cellulose fibers by the floating method, in carbon tetrachloride in a dry and air-free atmosphere, permitting an accuracy of one part per thousand. The density is derived from the temperature at which the samples neither sink nor float. This temperature varies, with the kind of fiber, between 45° and 65°C. Measurements of the refractive power were carried out simultaneously. The refractivity calculated according to Gladstone and Dale yields slightly lower figures than those found for model fibers in the preceding communication (Part II). The average difference amounts to seven parts per thousand and is ascribed to a systematic error in the density determinations, due to a slight absorption of carbon tetrachloride by the fibers at elevated temperatures. This explanation is supported by experiments. The density of native ramie, of contracted and reoriented ramie, and of several series of rayon fibers spun with increasing stretch, is given. The conclusion is reached that the density is a measure of the percentage of crystalline substances in the fiber and it is shown that there is a correlation between density and sorptive capacity toward water vapor. The percentage of crystalline matter is estimated to be 55-60% in native ramie and 20-25% in rayon.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010303
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    Statistical behavior of the single chain molecule and its relation to the statistical behavior of assemblies consisting of many chain molecules (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 183-199 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The molecules of high-molecular substances, for instance, those present in rubber, can be treated statistically in two ways. On the one hand, these molecules are such complicated structures that it is possible to attribute a separate entropy and free energy to each giant molecule. On the other hand, solutions of high-molecular substances represent systems in which the single chain molecule is the elementary particle, and to which statistical considerations and concepts such as entropy and free energy can be applied. Depending upon the parameter considered, the same chain molecule must sometimes be treated as a complicated system and at other times as an elementary particle. The problems originating from the simultaneous existence of two stages in the statistical treatment are examined. It is shown that the entropy of an assembly of many chain molecules is not simply equal to the sum of the entropies of the separate chain molecules. This becomes apparent particularly when determining the distribution function with respect to a particular parameter (e.g., distance between the two end points of a molecule) from a statistical consideration of the single molecule on the one hand, and from a consideration of an assembly of identical molecules on the other hand. The relations between entropy and free energy of the individual particle and the a priori probabilities on which the treatment of an assembly is to be based are explained. It is further shown that the same particle can give rise to a macroscopic phenomenon in two ways and to approximately the same extent: first, as a complicated system, and second, as an element in a large assembly of identical particles. This applies in particular to the elastic retractive force and to the strain birefringence in rubber and related substances.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010306
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    Preparation and properties of rubberlike high polymers. I. Polymerization of dienes and vinyl compounds in bulkCommunication No. 53 from the Rubber Foundation. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 200-216 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polymerization of dienes under the influence of heat, of diazoaminobenzene, and of benzoyl peroxide, has been studied. Diazoaminobenzene probably acts as a slow, but continuous, source of free radicals giving quantitative yields of methyl rubber of good quality from dimethylbutadiene after a few days to a few weeks at 100-125°C. The effect of diazoaminobenzene on butadiene is the same, but the rate of the uncatalyzed dimerization of butadiene at 100°C. is as fast as that of dimethylbutadiene at 150°C. and, therefore, dimerization interferes much more strongly with the polymerization of butadiene. Only 60% of polybutadiene has been obtained. A few experiments with isoprene showed its position between the two other dienes. The effect of benzoyl peroxide on the polymerization of the dienes appeared to be much smaller than was expected from its known catalytic action on the polymerization of vinyl compounds, e.g., styrene, for in this case its activity is about 100-1000 times greater than that of diazoaminobenzene. It is assumed that a larger number of radicals, produced by the fast decomposition of benzoyl peroxide, causes this difference. Diazoaminobenzene has about the same effect on the polymerization of styrene and acrylonitrile as on that of the dienes. The catalytic effect of benzoyl peroxide on the polymerization of the dienes is, on the contrary, 10,000-100,000 times smaller than on that of the vinyl compounds. This difference can be understood by the assumption that the catalyst is quickly used up by oxidizing the dienes and their polymers. While methyl rubber and the polyisoprene resemble raw natural rubber, polybutadiene, prepared under comparable conditions, is hard, swells moderately, and has a tendency to become brittle as a result of oxidation (aging). Abbreviations used are DAB (= diazoaminobenzene) and BP (= benzoyl peroxide).
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010307
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    The photochemical decomposition of cellulose acetate-butyrateCommunication No. 1018 from the Kodak Research Laboratories. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 217-224 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The chief result of irradiation of cellulose acetate-butyrate with ultraviolet light is cleavage of the cellulose chains so that the average molecular weight is lowered. The exposed material dissolves more slowly in common solvents than the unexposed. The acyl content and carbon and hydrogen contents are not altered appreciably. The rate of the reaction is independent of the type of common mineral impurities, the concentration of expected decomposition products, such as acetic and butyric acids, and the molecular weight of the cellulose ester. Ultraviolet light is necessary for appreciable reaction. Wave lengths shorter than 3500 Å. are most effective; longer wave lenghts are much less active.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010308
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    Elastic deformation and molecular weight in polyisobutylene (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 225-228 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A rapid procedure is described for estimating the average molecular weights of polyisobutylenes from deformation-rate measurements.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010309
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    Determination of catalyst fragments in polymers by absorption in the ultraviolet (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 229-230 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    URL: http://dx.doi.org/10.1002/pol.1946.120010310
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    Polymerization of allyl methacrylate by means of ultraviolet radiation (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 230-231 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010311
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    On the structure of the protein molecule. A chemical investigation. By N. TROENSEGAARD. Munksgaard, Copenhagen; Oxford University Press, London. 2nd edition, 1944. 126 pp. In English. 14.00 Danish kroner (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 232-232 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    URL: http://dx.doi.org/10.1002/pol.1946.120010312
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    Use of a stopcock device for sampling latex (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 245-246 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A device is described which permits rapid sampling of systems under pressure.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010403
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    Relation between molecular weight and intrinsic viscosity for polymethyl methacrylate (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 237-244 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The chain lengths of polymethyl methacrylates prepared with ferrous ion-hydrogen peroxide as the initiating system are consistent with the scheme advanced for the mechanism of the polymerization. The relation between intrinsic viscosity in benzene and molecular weight for fractionated polymethyl methacrylate has been determined and leads to the equation: n = 2.81 × 103 [η]C6H61.32. This equation agrees very well with the data of Schulz, provided that the correct method of extrapolating the osmotic pressures to zero concentration is used. Using the relationship between [η]C6H6 and [η]CHCl3 obtained experimentally, the relation between n and [η]CHCl3 (at 20°C.) is: n = 1.81 l3 × 103[η]CHCl31.22.
    Additional Material: 3 Ill.
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    Sedimentation and diffusion of cellulose moleculesCommunication No. 30 from the Institute for Cellulose Research. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 233-236 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is shown that the sedimentation and diffusion constants of cellulose at infinite dilution conform with a formula derived on the assumption of randomly coiled structures. The principle is introduced that the sedimentation velocity of closely packed particles moving through a liquid exerts an influence on their motion, according to known hydrodynamic laws.
    Additional Material: 2 Ill.
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    Comparison of ultraviolet absorption and chlorine analysis methods for composition of butadiene-p-chlorostyrene copolymersThis work was carried out under the sponsorship of the Office of Rubber Reserve, Reconstruction Finance Corporation, in connection with the Government Synthetic Rubber Program. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 247-248 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A comparison has been made of the ultraviolet spectrophotometric and chlorine analysis methods for the composition of copolymers of butadiene and p-chlorostyrene. The results of the two methods are in good agreement.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010404
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    Use of density-gradient tube in the study of high polymers (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 249-258 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The density-gradient tube is a special glass vessel in which a vertical linear density gradient of almost any desired magnitude can be maintained in a stable condition for prolonged periods by using liquids or solutions of the proper density. This article describes the application of such a device to three typical problems appearing in the field of high polymers: crystallization-rate data, inhomogeneities in composition of copolymers, and rates of polymerization. Possible application to still other problems is indicated.
    Additional Material: 7 Ill.
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    Technique of electron-microscope investigation of fiber surfacesPresented in part before the Electron Microscope Society at Princeton University, November 30 and December 1, 1945. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 259-265 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The technique of obtaining polystyrene silica replicas from surfaces and cross sections of fibers is described and electron micrographs obtained from replicas of several fibers are shown.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010406
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    Silver dichroism of micellar systems with fibrous structures (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 266-274 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By embedding submicroscopic silver rodlets in micellar systems with fibrous structures, unexpectedly strongly anisotropic rodlet compounds bodies are formed. The observed dichroism, indigo blue-straw yellow, suggests the possibility that a particular anisotropic modification of silver is being dealt with, instead of cubic silver. On applying Wiener's compound body formulas, it appears, however, that in the short-wave region the observed anisotropic effects (negative rodlet double refraction and dichroism) can be computed from the optical properties of isotropic silver. In the spectral region of the average and long waves, differences are found between the observed anisotropy and the value calculated by means of Wiener's formulas. These differences are, however, not of such a nature that it is necessary to assume an unknown allotropic modification of silver with particular optically anisotropic properties in order to explain them.
    Additional Material: 5 Ill.
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    β-Aminoethoxyl- and β-cyanoethoxylcellulose acetatesHoffman-LaRoche, Inc., Nutley, N. J. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 289-292 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mixed cellulose acetate-ethers were prepared which contain basic-type nitrogen groups whose films were dyed by xylene brilliant blue. β-Aminoethoxylcellulose acetate was prepared from cellulose diacetate and yarn-type cellulose acetate-propionate using ethyleneimine. β-Cyanoethoxylcellulose acetate was prepared from β-cyanoethoxylcellulose and from cellulose acetate using acrylonitrile with an organic base as catalyst. The solubilities of the mixed ether-esters containing basic type nitrogen groups were less than those of cellulose esters and ethers of comparable degrees of substitution.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010409
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    Sodium-catalyzed copolymerization of 1,3-butadiene and styreneThis investigation was carried out under the sponsorship of the Office of Rubber Reserve, Reconstruction Finance Corporation, in connection with the Government Synthetic Rubber Program. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 275-288 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Butadiene and styrene have been copolymerized by the use of sodium sand as a catalyst. The copolymers containing 75 parts of butadiene and 25 parts of styrene and made at 30° and 50° are soluble in benzene and have intrinsic viscosities ranging from 2.5 to 7.5. The copolymers has a very nearly constant composition throughout the course of the polymerization. The amount of butadiene which has entered the chain by 1,2 addition is greater than in the case of the emulsion copolymer.
    Additional Material: 14 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010408
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    Modern views on the chemistry of vulcanization changes. I. Nature of the reaction between sulfur and olefinsThe work described in this series of papers forms part of a program of fundamental research undertaken by the Board of the British Rubber Producers' Research Association. The experimental details will be published formally at a later date. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 293-304 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Whatever additional factors may be concerned in the production of good vulcanizates from natural rubber by the action of sulfur, there is no doubt that the action of sulfur on olefinic materials in general at the ordinary vulcanization temperature is a chemical one, the primary course of which is determined largely by the constitution of the olefin, and hence may be profitably studied by experimentation with olefins of different unsaturation patterns. Unaccelerated reaction between sulfur and simple monoolefins leads almost exclusively to cross linking of the separate olefin molecules, mostly in pairs, by groups of sulfur atoms. When, however, two or more olefinic units occur in the same molecule, as in the disoprenic hydrocarbons, intramolecular cross linking, i.e., cyclization, at once becomes possible, and the result of sulfur action consists partly in the cross linking of separate molecules as with the monoolefins, but largely in cyclization of the individual olefinic chains, thereby forming sulfur-containing rings. These changes entail a certain loss of unsaturation, from which deductions can be made as to the mechanism of the reaction.
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    Composition of butadiene-styrene copolymers prepared by emulsion polymerizationThis work was carried out on a contract with the Office of Rubber Reserve, Reconstruction Finance Corporation, in connection with the Government Synthetic Rubber Program. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 318-328 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Experimental data are presented on the monomer composition of copolymers of butadiene and styrene prepared by emulsion polymerization at 50°C. The composition of the copolymers is shown to be unaffected by variations in the amount of emulsifier, of mercaptan, and of the nature of the water-soluble polymerization catalyst. The composition of the copolymers formed from a charge containing 25% styrene (by wt.) can be represented accurately over the entire conversion range by the approximate theory according to which each monomer disappears by a first order reaction with the growing chain of the polymer, without taking into account the fact that the end of the growing chain to which the monomer adds may be a radical derived from either of the two monomer molecules. If the ratio of monomers in the charge is varied within wide limits, however, it is found that the simple theory is not adequate and it is necessary to consider that the chain may end with different radicals. The analysis of the experimental data shows that a butadiene molecule adds more rapidly than a styrene molecule to a radical derived either from a butadience or a styrene molecule.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010413
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    Modern views on the chemistry of vulcanization changes. III. Reaction of sulfur with squalene and with rubberThe work described in this series of papers forms part of a program of fundamental research undertaken by the Board of the British Rubber Producers' Research Association. The experimental details will be published formally at a later date. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 312-317 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Squalene containing six isoprene units is more free of end-group effects and less limited in the range of space-distributional contortions of its carbon chain than mono- and diolefins. Hence it is more comparable with rubber than the latter group where matters of chemical reactivity are concerned. Nevertheless, in its reaction with sulfur, squalene pursues a course very similar to that followed by the diisoprene, dihydromyrcene, in that intramolecular sulfide linkages as well as intermolecular polysulfide linkages are formed. Taking into consideration the amount of sulfur which would suffice for the establishment of some given number of the simplest possible intermolecular linkages (i.e., monosulfide linkages), the efficiency of sulfur as a cross-linking reagent during the vulcanization of squalene is seen to be of a rather low order; this condition might be expected to hold for rubber in the absence of auxiliary mechanisms. So far as can be determined by direct experiment the action of sulfur in forming cross links is not essentially different from that encountered with squalene, since there are indications that both intra- and intermolecular sulfide linkages are formed - the latter being of both dialkenyl and dialkyl sulfide type, and, possibly also of alkenyl alkyl type. Under the influence of small amounts of zinc oxide or of various nitrogen-containing organic accelerators, sulfur reacts with the thiol groups of organic mercaptans forming di- and polysulfides, together with hydrogen sulfide. In the presence of rubber the same reaction occurs without actual liberation of hydrogen sulfide and it thus appears that if any thiol groups are formed as intermediates in vulcanization reactions, they will undergo ready conversion into intermolecular di- and polysulfide linkages. This may well represent an important auxiliary mechanism of cross linking.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010412
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    Modern views on the chemistry of vulcanization changes. II. Role of hydrogen sulfideThe work described in this series of papers forms part of a program of fundamental research undertaken by the Board of the British Rubber Producers' Research Association. The experimental details will be published formally at a later date. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 305-311 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydrogen sulfide has often been thought to play an important role in the sulfur vulcanization of natural rubber. A study has therefore been made of the reaction of hydrogen sulfide with olefins, including polyisoprenes, with special reference to the capacity of the reagent to react with olefins in the presence of free sulfur. Comparison of the products so obtained with those derived (a) by light-catalyzed reaction of hydrogen sulfide and (b) by reaction of free sulfur with polyisoprenes has greatly assisted the understanding of the course of sulfur reaction in vulcanization processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010411
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    Determination of persulfate in emulsion polymerization laticesThis investigation was carried out under the sponsorship of the Office of Rubber Reserve, Reconstruction Finance Corporation, in connection with the Government Synthetic Rubber Program. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 340-352 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the emulsion polymerization of butadiene, styrene, or both, potassium persulfate is often used as the catalyst. A convenient concentration of potassium persulfate in the aqueous layer of the charge is 0.10-0.2%; the method of analysis should therefore be suitable for very small persulfate concentrations. Three methods have been investigated. In the volumetric method the persulfate is allowed to react in an acid medium with an excess of standard ferrous iron, the excess being back-titrated after a given period of time with standard ceric cerium solution. The recommended procedure was found accurate and precise within 0.5%, even at such small concentrations as 5 mg. of potassium persulfate per 100 ml. When latex is analyzed by this method, the polymer is first removed by coagulation with sulfuric acid and the persulfate determined in the filtrate. In order to obtain reliable results the reaction between the persulfate and ferrous iron in the filtrate must be carried out in the absence of oxygen, although this is not necessary in solutions of pure persulfate. The interference by oxygen is attributed to substances of peroxidic character in the fatty acid soaps used as emulsifiers in the emulsion polymerization. The colorimetric method (“Becco” method) is based upon the oxidation of the leuco base of commercial wool green BSMA to a green dye by the persulfate and (colorimetric) measurement of the dye formed. The various factors affecting the accuracy and precision of this method have been investigated and a procedure is given for the analysis of latex. For several reasons, the volumetric and polarographic methods are superior to the colorimetric method. Persulfate in a latex can be determined accurately by polarographic analysis of the latex filtrate after removal of the polymer with sulfuric acid. The polarographic determination can be carried out, in the presence of oxygen, with simple equipment. The method is rapid and precise.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010502
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    Deformation mechanism of cellulose gels. I. Present status of the problemCommunication No. 31 from the Laboratory for Cellulose Research, Utrecht. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 389-392 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A brief outline is given of the present status of research on the problem of the deformation mechanism of cellulose gels. Emphasis is placed on the prevailing idea of a molecular network structure and recognition of the existence of an intimate relationship between the phenomena of deformation and those of swelling. In these respects the problems involved in cellulose research seem to show a marked convergence with those which emerge from recent developments in rubber research. The principle of Kratky's theory of “affined transformation” and the experiments carried out by this author in order to verify his theory are discussed briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010506
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    Deformation mechanism of cellulose gels. II. Course of crystallite orientation compared to that required by Kratky's theoryCommunication No. 32 from the Laboratory for Cellulose Research, Utrecht. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 393-406 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The paper offers a verification by x-ray experiments of Kratky's theory of affined transformation (affine Raumverzerrung), aiming at an explanation of the mechanism of deformation of swollen cellulose gels upon stretching. Isotropic model filaments of various degrees of swelling were stretched to various extents and x-ray photographs were then taken. Following Kratky, the intensity distribution along the sickles of two paratropic planes of the ribbon-shaped crystallites, the lamellar plane, A0 and the A3 plane (perpendicular to the latter) were measured and the average orientation, expressed in terms of the orientation factor, fx, was calculated. The superposition of the (021) interference on that of the A3 sickle, which had been neglected by Kratky, was accounted for. The experimental results are in conformity with certain characteristic features of the theory; (a) the orientation of the A0 planes advances more rapidly than that of the A3 planes; (b) regardless of the initial degree of swelling of the isotropic filament, the average orientation is actually a univocal function of the elongation, va. On the other hand, the rate of orientation appears to be much greater than that required by theory; the average orientation, expressed in terms of the orientation factor, increases almost twice as rapidly. It is shown, moreover, that, apart from low degrees of orientation, Kratky's theory fails to explain the velocity function of the relative rotation of the crystallites, as derived from the experimental data according to a procedure proposed by Kratky. It is concluded that further work is required to elucidate the mechanism of deformation.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010507
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    Nature of the carbonyl groups in polyvinyl alcohol (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 419-428 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of the viscosity of polyvinyl alcohol solutions may be correlated with the chemical nature of the polymer. In particular it is shown that polyvinyl alcohol contains carbonyl groups in the polymer chain, which are to some extent present as ketols. The presence of these keto groups has been demonstrated by a combination of spectrophotometric and chemical techniques. The carbonyl groups appear to be randomly distributed along the polymer chain and also seem to be independent of chain length. The presence of keto groups along the chain allows an explanation for the behavior of aqueous polyvinyl alcohol solutions with acid or alkali.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010509
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    Determination of polystyrene in GR-S rubberThis investigation was carried out under the sponsorship of the Office of Rubber Reserve, Reconstruction Finance Corporation, in connection with the Government Synthetic Rubber Program. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 429-433 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A convenient procedure for the determination of polystyrene in GR-S is given. The method depends upon degradation of the GR-S by tert-butyl hydroperoxide in the presence of a trace of osmium tetroxide. Polystyrene is not attacked and is separated by precipitation with ethanol.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010510
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    Application of the density-gradient tube in fiber research (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 437-439 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1946.120010512
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    Polymerization of methyl methacrylate in aqueous emulsions (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 466-474 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the polymerization of methyl methacrylate in emulsions has been examined. The initial rate of polymerization is independent of the amount of discontinuous monomer phase present and it is concluded that initiation occurs in the aqueous phase. Monomer is observed to disappear from the discontinuous phase more quickly than it polymerizes, and probably forms a monomer-polymer mixture with the polymer produced. An increase in the subsequent rate of polymerization is attributed to the fact that propagation of the growing polymer chains occurs in this monomer-polymer mixture and this entails a decrease in the velocity of termination due to the high viscosity of such mixtures.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010604
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    Reactivity of monomers in copolymerization (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 455-465 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An investigation of the copolymerization of many monomer pairs induced by benzoyl peroxide has shown that an order of monomer reactivity with radicals exists. By utilizing the data available, it was possible to make a semiquantitative arrangement of many monomers according to their relative rates of reaction with radicals. A symmetrical selectivity factor is assumed to account for deviations from the order in copolymerization reactions. This selectivity may be attributed to (1) complex formation between monomers or to (2) dipole, steric, or other factors which are independent of concentration. Copolymerization equations have been derived for each case and application of them to styrene-methyl methacrylate mixtures has indicated that selectivity due to (2) is most important in this system. The equation for case (2) has been applied to other copolymer systems.
    Additional Material: 11 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010603
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    Theory of rolling plastics. I. Calculation of roll pressurePublished by permission of the Chief Scientific Officer, Ministry of Supply, England. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 529-534 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An elementary theory is given for the rolling of polymeric materials, for the case in which the deformation is largely an irreversible flow of the viscous type. The theory treats the rolling process as the homogeneous deformation of volume elements over the arc of contact and neglects frictional forces that may exist at the roll surface. A numerical example is given of the calculation of roll pressure, which agrees with available data to a factor of two or better. A more complete test will require parallel measurements of viscosity and roll pressure on the same material.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010608
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    Investigation of potato proteins (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 484-494 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By treating potato juice with acid it was found that potato globulin is converted to albumin and an insoluble casein-like protein. Potato albumin, salted out with ammonium sulfate and purified by dialysis, is very similar to ovalbumin; it is reconverted into a globulin-like protein by alkali. Solutions of potato albumin in water, as well as in acids and alkali, have a very low viscosity. Alkaline solutions of globulin have a greater viscosity than those of albumin; the viscosity numbers of the difficulty soluble protein are even greater. On the basis of the viscosity data, it was concluded that the albumin particles are corpuscular, the globulin molecules are longitudinal, and that the dissymetry is greatest for the difficulty soluble protein particles. On the basis of the different solubilities of all three proteins (which apparently have approximately the same chemical composition), it was concluded that the albumin molecule was the smallest and the difficulty soluble protein molecule the largest. An aqueous solution of potato albumin is denatured when heated to 50-60°, the viscosity thereby increasing more than 100-fold. The solutions become only slightly turbid, but do not flocculate. This unusual viscosity rise can be explained by the transformation of globular albumin molecules into fibrous, elongated particles. Only a slight viscosity increase is observed when alkaline solutions of albumin are heated. Albumin, in the presence of small amounts of salt, is precipitated at 50-60°; the salts also lower the turbidity point. However, very small concentrations of calcium chloride have a stabilizing effect. Albumin is not coagulated at room temperature by 1-2 N salt solutions. The experiments on the effect of cold on potato albumin showed that albumin, after congealing and thawing out, was more easily precipitated than the control solution. The viscosity of the cold-damaged albumin was somewhat less than that of the control solution. It was ascertained that the deaminated product of potato albumin was very similar to deaminated ovalbumin (solutions of high viscosity; linear colloid).
    Additional Material: 10 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010606
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    Heat polymerization of nonconjugated vegetable oilsPresented in part before the Division of Paint, Varnish, and Plastics Chemistry at the 108th Meeting of the American Chemical Society, New York, N. Y., September, 1944. (1946)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 1 (1946), S. 495-528 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A general theory is proposed to account quantitatively for the heat polymerization and gelation of the nonconjugated vegetable oils. This is based on a direct approach to polyfunctionality as developed from quantitative considerations of partial random distribution of the fatty acid components in the triglyceride molecules. The differing polymerization rates of linseed and soybean oils are accounted for on the basis of the assumed influence of certain cis-trans geometric isomers. The theory accounts for the anomalous extensive linear polymerization and nongelation of olive oil. Calculations from the theory agree substantially with experimental results on average molecular weight, iodine value, and the percentage of insoluble, infusible cross-linked polymers.
    Additional Material: 24 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1946.120010607
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    Biochimica et Biophysica Acta, Volume 1, No. 1, (1947). Elsevier, New York-Amsterdam; Interscience, New York. 100 pp. Price $9.00 (annual subscription, 6 to 8 issues) (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 349-349 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020313
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    The chemistry of free radicals. W. A. WATERS. Clarendon Press, Oxford, 1946. 295 pp. Price $6.50 (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 349-350 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020314
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    Refractometric determination of second-order transition in polyvinyl acetate (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 10-11 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The refractive index-temperature data for polyvinyl acetate show a second-order phase transition temperature of 24°C.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/pol.1947.120020102
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    Polyelectrolytes. I. Picrates of 4-vinylpyridine-styrene copolymersSupport of this work by a contract with the Office of Naval Research is gratefully acknowledged by the authors and the University. (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 12-15 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The conductance in diphenyl ether at 35°C. and 60 cycles of the picrate of a 4-vinylpyridine-styrene copolymer (10:90) has been measured. The equivalent conductance, based on the nitrogen content, is of the same order as that of picoline picrate, and varies with concentration in accordance with the law of ion association.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1947.120020103
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    Intrinsic viscosities and molecular weights of polyvinyl acetatesCommunication No. 1122 from the Kodak Research Laboratories. (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 21-35 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A polyvinyl acetate polymer of medium viscosity was fractionated into sixteen fractions (first series) and three of the larger of these further separated into twenty subfractions (second series). The intrinsic viscosities and the osmotic pressure molecular weights were determined at 25°C. and the relation between them was found to be expressed by the equations: first series: [η] = (1.88 × 10-4) M0.69; second series: [η] = (1.76 × 10-4) M0.68. The data indicate that little, if any, increase in homogeneity is to be expected by further successive fractionations and that the equations applicable to the second fractionation series are representative of essentially homogeneous polyvinyl acetates in acetone. An equation applicable to fractionated and unfractionated vinyl acetate polymers is described that is useful in obtaining the intrinsic viscosity from a single viscosity measurement. Several unfractionated materials from different sources were also studied and the calculated ratios of the viscosity-average to the number-average molecular weight indicate that the degree of heterogeneity of chain-length distribution increases with increasing average molecular weight.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1947.120020105
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    Contributions to the physics of cellulose fibres. P. H. HERMANS. Elsevier, New York-Amsterdam, 1946. In English. 221 pp. Price $4.00 (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 354-354 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020321
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    German plastics practice. BY JOHN M. DE- BELL, WILLIAM C. GOGGIN, and WALTER E. GLOOR. DeBell and Richardson, Springfield. Massachusetts, 1946. Published with permission of the Department of Commerce. vii and 555 pp. Name and subject indexes, glossary. Price $7.50 (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 353-354 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020320
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    Influence of structure on polymer-liquid interaction. I. Relative and absolute values of swelling equilibriaCommunication No. 62 from the Rubber Foundation. (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 355-370 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The swelling of vulcanized natural rubber, Buna S, neoprene, Perbunan, and Perbunan Extra was measured in various organic liquids. The essential influence of polarizability and polarity on the swelling equilibrium is illustrated by comparing series of solvents and polymers with gradually changing geometrical and chemical structure. Experiments on the influence of temperature and of strain on the swelling equilibrium are reported. The swelling properties of ebonites and similar derivatives allow some conclusions on the amount of cross linking in these polymers.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1947.120020401
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    Diffusion of water vapor through high polymeric membranes (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 371-380 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Practical, theoretical, and experimental aspects, including sources of error and methods of control, of the water and water vapor permeability of organic membranes are discussed. Determinations of the permeability have been made at two different temperatures. Data are given on: polyethylene (alkathene, Imperial Chemical Industries), polystyrene (Styroflex, D. Seekabelwerke), chlorinated polyvinyl chloride (Vinifol, I. G. farbenindustrie), cellulose acetates (Triacetat, Schering, and Triafol, I. G. Farbenindustrie), a plasticized polyvinyl chloride (Welvic, Imperial Chemical Industries), and a copolymer of vinylidene chloride and vinyl chloride (Saran, Dow).
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1947.120020402
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    Heats of polymerization of acrylic acid and derivatives (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 387-396 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The heats of polymerization of acrylic acid, methyl acrylate, methacrylic acid, and methyl methacrylate have been measured. Values for the heat of polymerization of unstrained polymer molecules have been calculated, and the low heat of polymerization of methyl methacrylate has been attributed to the presence of steric hindrance in the polymer molecule.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1947.120020404
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    Solubility, diffusion, and permeation of gases in gutta-perchaCommunication No. 69 from the Rubber Foundation. (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 381-386 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The permeability of vulcanized gutta-percha membranes to gases was determined in relation to the rate of diffusion and solubility. The measurements, as functions of temperature, with four gases were taken below and above the melting point of gutta-percha. The evidence is that the rates of permeation and diffusion increase sharply at approximately 45°C., due to melting of the gutta-percha. In the same way, although to a lesser degree, the solubility of the gas likewise increases at the melting point. The activation energies of permeation and diffusion with the heat of solution were computed from the temperature function of those quantities. It follows from the results that crystallization of the elastomer reduces the gas-solubility, the diffusivity, and the permeability - and increases the activation energy of diffusion. The interpretation of this high activation energy of diffusion is that, because of the crystallization, the macromolecules of the membrane adhere so firmly that greater energy is required to admit the gas molecules.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020403
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    Course of acetylation and deacetylation reactions of cellulose fibers. I. Optical and swelling propertiesCommunication No. 46 from the Laboratory for Cellulose Research, Utrecht. (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 397-405 
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    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A description is given of the preparation, birefringence, and swelling capacity of a series of microscopically homogeneous, partially acetylated cellulose model filaments with an acetyl content varying from 0 to 2.3 acetyl groups per glucose residue, and obtained either by acetylation or by deacetylation. A higher degree of acetylation of these artificial fibers could not be attained without destruction of the fiber. The same holds true for native ramie fibers. The swelling was studied in water, acetone, and methanol. The degree of swelling of the filaments plotted against acetyl content yields entirely different curves for the acetylation and the deacetylation series. These curves can be readily explained by the hypothesis that the intercrystalline (so-called amorphous) portion of the fiber substance is more accessible to the esterification and saponification reactions and is affected earlier than the crystalline portion. The birefringence of the acetylation series shows but a small - although apparently real - difference from that of the saponification series.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020405
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  • 99
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    Multi-ingredient polyamidesContribution No. 214 from the Chemical Department. (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 412-419 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Multi-ingredient polymeric amides have been prepared by the condensation, under amide-forming conditions of various combinations and ratios of components comprising hexamethylenediammonium adipate, hexamethylenediammonium sebacate, and ∊-aminocaproic acid or ∊-caprolactam. The physical properties of the investigated linear polymeric amides range, depending upon the polymer components and the proportions employed, from high-softening, stiff, and difficulty soluble compositions to relatively low-softening, pliable, and easily soluble polymers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020407
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  • 100
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    Course of acetylation and deacetylation reactions of cellulose fibers. II. X-ray diagramsCommunication No. 47 from the Laboratory for Cellulose Research, Utrecht. (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 406-411 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A discussion is offered of the x-ray patterns of partially acetylated and saponified cellulose model filaments with varying acetyl contents. They are substantially in conformity with the swelling experiments previously described in Part I (page 397) of this paper. (1) In nonrecrystallized filaments, chemical reaction takes place in the crystallites and the intercrystalline regions from the very beginning of the experiment. The rate of chemical conversion, however, is larger in the latter. (2) Acetylation of the hydrate cellulose crystallites results in a gradual increase in the (101) spacing, A0; the A3 and A4 reflections [corresponding to (101) and (002), respectively] remain unimpaired up to a gross acetyl content of at least 1.5 acetyl groups per glucose residue. (3) Maximally acetylated filaments containing 2.3 acetyl groups per glucose residue may be recrystallized by heating in methanol or ethanol. The diagram of the recrystallized product is identical with the pattern of cellulose triacetate II. With about halfway acetylated or saponified products, recrystallization is not realizable by means of a heating process in water or methanol. (4) Enhanced degree of local order as the result of previous recrystallization of maximally acetylated products produces a more pronounced difference in rate of saponification between the “crystalline” and “amorphous” fiber portions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020406
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