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  • 1
    Electronic Resource
    Electronic Resource
    Calculation of the effects of annealing on Sub-Tg endotherms (1981)
    s.l. : American Chemical Society
    Macromolecules 14 (1981), S. 1598-1599 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma50006a092
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of annealing and prior history on enthalpy relaxation in glassy polymers. 5. Mathematical modeling of nonthermal preaging perturbations (1985)
    s.l. : American Chemical Society
    Macromolecules 18 (1985), S. 1980-1984 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00152a030
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  • 3
    Electronic Resource
    Electronic Resource
    The solubility of vinyl chloride in poly(vinyl chloride) (1975)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 47 (1975), S. 97-110 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Löslichkeit von Vinylchlorid (VCM) in PVC-Pulvern wurde für den Temperaturbereich von 30 bis 110°C durch Bestimmung des Gleichgewichtsdampfdruckes und durch Gravimetrie mit der Mikrowaage untersucht. Bei Temperaturen und VCM-Konzentrationen in PVC oberhalb des Glasübergangsbereiches folgt die Löslichkeit der Flory-Huggins-Gleichung mit χ = 0.98; die Löslichkeit unter diesen Bedingungen ist unabhängig von der Temperatur, vom Molekulargewicht, der Art des PVC und der PVC-Vorbehandlung. Andererseits ist die Löslichkeit im Glaszustand größer als nach der Flory-Huggins-Gleichung und zeigt starke Abhängigkeit von der Zeit und der PVC-Vorbehandlung. Diese Ergebnisse wurden durch den Dualsorptionsmechanismus von Michaels, Vieth, und Barrie interpretiert: Normale Auflösung folgt der Flory-Huggins Beziehung, während die zusätzliche Löslichkeit im Glaszustand sich durch Auffüllung der Mikrolücken ergibt. Änderungen der Löslichkeit mit der Zeit und der PVC-Vorbehandlung entsprechen den wohlbekannten Volumenrelaxationen. Messung der Dampflöslichkeit bietet daher ein unmittelbares, empfindliches Maß für das freie Volumen von Polymeren im Glaszustand.
    Notes: The solubility of vinyl chloride monomer (VCM) in PVC powders has been studied by equilibrium vapor pressure and microbalance gravimetric techniques at temperatures from 30 to 110°C. At temperatures and VCM concentrations above the glass transition, the solubility closely follows the Flory-Huggins equation with χ = 0.98 and is independent of temperature and of the PVC type, molecular weight, or history. In the glassy state, the VCM solubility is higher than the Flory-Huggins value and shows pronounced dependence upon time and the PVC history. These results have been interpreted through the dual-mode sorption concept of Michaels, Vieth, and Barrie: Normal dissolution follows the Flory-Huggins relation, and the additional glassy-state solubility represents the contribution of a hole-filling process. Changes in solubility with time and sample history parallel well-known volume relaxation processes, indicating that vapor solubility measurements offer a direct and sensitive measure of the free-volume state of glassy polymers.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1975.050470107
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  • 4
    Electronic Resource
    Electronic Resource
    The diffusion of gases and vapors in rigid PVC (1979)
    Brookfield, Conn. : Wiley-Blackwell
    Journal of Vinyl and Additive Technology 1 (1979), S. 8-13 
    Details
    ISSN: 0193-7197
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gravimetric sorption rate measurements have been carried out for (CO2, H2), and ten C1-C6 organic vapors at low concentrations (≤ 0.2%) in PVC films and uniform-particle powders at 30°C. The dominant transport process in all cases appears to be Fickian diffusion. A distinguishable contribution of relaxation-controlled swelling was observed for the more soluble vapors, such as acetone and benzene. A significant contribution of surface adsorption to the total sorption process was detected only for the n-alkanes, among the penetrants studied. Diffusion coefficients, determined from half-sorption times and polymer dimensions, range from 4 × 10 -8 cm2/sec for H2O to 1.5 × 10 -15 cm2/sec for n-hexane. Diffusivities determined in this study, in combination with those for gases reported by Tikhomorov, et al. (Makromol. Chem. 118 177 (1968)), define a continuous curve, covering more than nine orders of magnitude, when plotted as a function of the molar volume constant, b, of the van der Waals equation of state for gases and vapors.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/vnl.730010105
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  • 5
    Electronic Resource
    Electronic Resource
    Continuous emulsion polymerization of vinyl chloride (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 2379-2390 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: For batch emulsion polymerizations of vinyl chloride, the reaction rate can be well represented by the empirical expression dx/dt = k (1 + ax), where x is the polymer concentration, and k and a are constants dependent upon initiator concentration and particle number. A simple mathematical model for continuous stirred-reactor polymerizations has been derived from this expression. The model predicts that at short residence times, a steady state of low PVC concentration is reached quickly; with longer residence time, the system more slowly approaches a higher steady-state polymer concentration. Above a critical residence time, equal to 1/ak, the rate of monomer supply becomes the limiting factor. Experimental data on continuous polymerizations are in good qualitative accord with the predictions of the model using constants fitted to batch-charge data. Quantitative agreement is best when the particle number is large; discrepancies may be attributed to a broader particle size distribution in continuous runs. Particle size measurements show evidence of intermittent particle formation in unseeded continuous runs; continuous seeding narrows the particle size distribution, but it is still broader than in batch charges. The model seems sufficiently valid to yield a number of useful implications about practical aspects of continuous emulsion PVC polymerization.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180816
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis for vinyl chloride in PVC powders by head-space gas chromatography (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 3169-3172 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: At a temperature above the glass transition point of poly(vinyl chloride) (PVC), the solubility of vinyl chloride monomer (VCM) in PVC accurately follows Henry's law behavior for VCM contents up to 4000 ppm. This observation has lead to a rapid, simple gas-chromatographic method for the determination of VCM in PVC from the analysis of the vapor phase (head-space) over PVC powder samples in a sealed container. The basic experimental techniques, calculations, and examples of experimental data are given. The method can be used with any commercial gas chromatograph equipped with a flame ionization detector without instrument modification.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070191202
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  • 7
    Electronic Resource
    Electronic Resource
    Induction and measurement of glassy-state relaxations by vapor sorption techniquesPresented at the Second Cleveland Symposium on Macromolecules: “Structure and Properties of Amorphous Polymers,” Case Western Reserve University, Cleveland, Ohio, 31 October-2 November 1978. (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 17 (1979), S. 1757-1770 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Recent gravimetric studies of the sorption of organic vapors by poly(vinyl chloride) and polystyrene powders have demonstrated several features which promise to be generally useful in studying the structure and properties of the glassy state. The uptake of vapor can be significantly altered by prior thermal or vapor treatment of the polymer, apparently reflecting changes in the microvoid content or free volume of the polymer. Fickian sorption in sufficiently fine powders proceeds to equilibrium in a few minutes. Upon exposure of a polymer powder to an appreciable pressure of vapor, both a rapid Fickian sorption and a slower, relaxation-controlled sorption are observed. Superposition of these processes leads to widely varied sorption kinetics; a model comprising Fickian diffusion and first-order relaxation terms accurately describes the data and allows estimation of equilibrium and rate constants for both processes. After prolonged exposure, removal of a swelling vapor induces a slow reconsolidation of the polymer structure; this deswelling relaxation can be monitored by the decreasing amounts of vapor sorbed in repeated brief exposures to low vapor pressures, and can also be described by a first-order relaxation model. In this regard, the penetrant vapor serves as a molecular probe, monitoring glassy-state relaxation occurring in the absence of penetrant. The same, presumably true equilibrium is ultimately reached both by swelling from a low free-volume state and by consolidation from a preswollen state of high free volume. The rates of both swelling and consolidation relaxations appear to be retarded by the presence of low concentrations of vapor in the polymer, suggesting that vapor molecules may preempt some of the free volume required for relaxation.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.180171011
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  • 8
    Electronic Resource
    Electronic Resource
    The significance of a particle-flow process in PVC melts (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 5-10 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080103
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  • 9
    Electronic Resource
    Electronic Resource
    The concentration and possible source of unstable sites in PVC (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 318-321 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Copolymers of vinyl chloride with 2-chloropropene were prepared as models for tertiary-chlorine branching in PVC. Rates of thermal dehydrochlorination of copolymers containing up to 2 mol percent 2-chloropropene were found to be a linear function of composition. By comparing the decomposition rates of the copolymers with that of PVC prepared under similar conditions, we estimate the maximum tertiary-chlorine content of PVC at 0.1 to 0.2 mol percent. This figure is of the same magnitude as estimates of the content of tertiary-chlorine, random unsaturation, and long-chain branching obtained in previously published studies of PVC. Possible mechanisms for tertiary-chlorine branch formation include chain-transfer to polymer and copolymerization with unsaturated chain-ends. By applying the conventional copolymerization equation, using the reactivity ratios of the vinyl chloride/2-chloropropene system, it is shown that the copolymerization mechanism predicts a tertiary-chlorine branch content close to the estimated value. Both mechanisms also agree qualitatively with reported effects of polymerization temperature and conversion on branching and thermal stability.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140503
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  • 10
    Electronic Resource
    Electronic Resource
    Prediction of vinyl chloride monomer migration from rigid PVC pipe (1976)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 552-558 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Data on the solubility and diffusion of vinyl chloride monomer (VCM) in PVC resin powders have been combined with published solutions of Fick's diffusion equation to yield predictions of the amount and rate of loss of residual VCM (RVCM) from rigid PVC pipe under storage and service conditions. The principal factors controlling VCM migration are the initial VCM content, thickness of the PVC section, temperature and the age of the PVC product. Analysis Solutions are presented for RVCM loss from freshly exturded pipe (uniform VCM concentration) into either the storage environment or the pipe contents. From these solutions, estimates are made for the real-world situation of closed-system service following variable storage periods. The validity of this approach for rigid PVC pipe in water-service is supported by reasonable agreement between its predictions and experimental laboratory data on the VCM content of water stored in PVC pipes. Both the predictive model and experimental data indicate that PVC pipe containing ≤ mg/kg (1 part per million) residual VCM will result in VCM concentrations in water of less than 0.002 mg/kg - under any expected service conditions.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760160805
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