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  • 1
    Electronic Resource
    Electronic Resource
    Polybutadiene/polystyrene interpenetrating polymer networks (1972)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 12 (1972), S. 101-108 
    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: Interpenetrating polymer networks (IPN's) of polybutadiene (PB) and polystyrene (PS) were prepared using both random (containing 36% cis, 55% trans, and 9% 1,2 vinyl) PB and high-cis PB. For both series, a wide range of PB/PS compositions were synthesized. Using samples stained with osmium tetroxide, electron microscope studies revealed an irregular cellular structure of a few hundred Ångstrom diameter with the first component, PB, making up the cell walls. The size of the cells was found to depend on the PB crosslink density for the random materials. Modulus-temperature data revealed two distinct glass transitions, confirming the microscopy finding of two phases. However, the transition temperature and transition slope varied with composition, and with the microstructure of the polybutadiene, giving evidence of significant molecular mixing. Stress-strain data on the IPN's showed that materials rich in PB behave like self-reinforced elastomers. Charpy impact resistance experiments on materials rich in PS indicated values of 5 ft-lb/in. of notch, which compares well with graft-type polyblends of similar PB/PS composition. The results were interpreted in the light of the recent theoretical work of Bragaw, who considered the importance of the distances between domain boundaries with respect to crack acceleration mechanics. Although the IPN's considered herein exhibited somewhat less than the predicted optimum phase dimensions, the arrangement of the domains is different from ordinary impact resistant plastics.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760120205
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  • 2
    Electronic Resource
    Electronic Resource
    Phase structure and continuity in polymer blends and composites (1976)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 87-92 
    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: Polymer blends and composites are composed of two different components, and usually, two different phases. Sometimes one phase is continuous and the other clearly discontinuous. Often, however, both phases retain some degree of continuity, as in certain fiber reinforced composites, block copolymers, materials composed of alternating lamellae structures and interpenetrating networks. A semi-empirical theory is developed to express mathematically not only the known structures, but also two-phase morphologies not yet synthesized or characterized. Many structures both real and proposed are shown to exhibit dual phase continuity, although for most systems, one phase can be said to be “more continuous” and the other “less continuous”.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760160205
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  • 3
    Electronic Resource
    Electronic Resource
    Poly(n-Butyl acrylate)/polystyrene interpenetrating polymer networks and related materials. II. Aspects of molecular mixing via modulus-temperature studiesWhen I joined Prof. A. V. Tobolsky's laboratory in July, 1965 as a Postdoctoral Research Associate, I had the pleasure of sitting in the exact chair that Mitch had vacated a few days earlier. While the other students in the laboratory told me of mitch's outstanding capabilities, I did not meet him personally until a few years later.Two areas of Mitch's research particularly attracted my attention. The first was his study of the thermodynamics of rubber elesticity, which contributed enormously to our understanding of the front factor and ƒe/ƒ, the internal energy contrubution to the retractive force.Later, Mitch became interested in gradient polymers, or gradient interpernetrating polymer networks. Some of his compositions were amazingly tough plastics. The science of IPN's will surely be hurt by the incomplete nature of these experiments caused his premature death. L. H.S (1981)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 21 (1981), S. 696-702 
    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: The glass transition, rubbery modulus, and tensile behavior of poly(n-butyl acrylate)/polystyrene interpenetrating polymer networks (IPN's), semi-1 IPN's, and their corresponding random copolymer networks were studied as a function of both composition ratio and crosslink density. Two temperatures were selected for analysis: 25°C, halfway between the two transition temperatures, and at 160°C., in the rubbery plateau region. The modulus data at 25°C were compared with wellknown composite models. The moduli of the IPN's and semi-1 IPN's lie close to the Davies model in the polymer II rich region but follow the Budiansky model in the polymer I rich region. In one interpretation of the Coran-Patel model, a phase inversion takes place around φ2 = 0.8, which is higher than the composition at which the phase connectivity of polymer II begins to appear, φ = 0.5, via electron microscopy studies. The rubbery modulus behavior of the full and semi-1 IPN's follow the equation of Siegfried, et al. reasonably well, which considers the deformation effect of polymer I in terms of the rubber elasticity front factor.The stress-strain behavior of both the full and semi-1 IPN's was similar to that of toughened plastics at polymer II rich compositions, and to that of reinforced elastomers at polymer I rich compositions.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760211111
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  • 4
    Electronic Resource
    Electronic Resource
    Characterization of polymer conformation and morphology through small-angle neutron scattering - A literature review (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1-21 
    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: Small-angle neutron scattering, SANS, stands forth as one of the most important of the new tools for evaluating polymer chain conformation and morphology. This paper reviews the SANS literature through 1982, with a few early 1983 references added. The theory of SANS is outlined and compared to light scattering. SANS values of polymer molecular weights and radii of gyration obtained in the bulk state were found to be in agreement with values obtained from dilute solutions by light scattering. In each case, deuterated fractions of polymer were inserted into the hydrogeneous matrix, or vice versa, to provide contrast. Several new research areas are then discussed, including unidirectional stretching of elastomers, stress-relaxation, polymer-polymer miscibility, crystallization from the melt compared with crystallization from dilute solutions, nonclassical aggregation during bulk polymerization of thermoset systems, morphology of polymer blends, block copolymers and ionomers, the core-shell structure of latexes and polymer blocks, and grafts as surfactants in emulsions and latexes. Much new and sometimes unexpected information is being provided by the SANS research now in progress.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240102
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  • 5
    Electronic Resource
    Electronic Resource
    Phase continuity and inversion in polymer blends and simultaneous interpenetrating networks (1986)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 26 (1986), S. 517-524 
    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: A semi-empirical expression for predicting phase continuity and inversion in polymer blends and simultaneous interpenetrating networks (SINs) was developed and examined experimentally. A rheological model based on the volume fraction, φ, and viscosity, η, led to the equation \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{{\rm \eta }_{\rm 1} }}{{{\rm \eta }_{\rm 2} }} \cdot \frac{{\phi _{\rm 2} }}{{\phi _{\rm 1} }} \cong 1 $$\end{document} as the criteria for dual phase continuity for phases 1 and 2. This relation was evaluated for two systems: a castor oil polyester-urethane/polystyrene SIN, and a mechanical blend of polystyrene and polybutadiene. Literature data was also examined. A gradual phase inversion was found, with a region of dual phase continuity in between. While predictions of phase continuity were confirmed for the mechanical blends, they were not confirmed for the SIN system. This was probably due to rapid gelation at the point of phase inversion.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760260802
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  • 6
    Electronic Resource
    Electronic Resource
    Molecular demixing in poly[cross-(ethyl acrylete)]-inter-poly[cross-(methyl methacrylate)] interpenetrating polymer networks brought about by selective decrosslinking and annealing (1986)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 26 (1986), S. 730-735 
    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: The extent of molecular demixing of poly[cross-(ethyl acrylate)]-inter-poly[cross-(methyl methacrylate)] interpenetrating polymer networks (PEA/PMMA IPNs), of mid-range composition was investigated by decrosslinking and/or annealing using dynamic mechanical spectroscopy. A single broad transition characteristic of extensive but incomplete molecular mixing was observed for the PEA/PMMA IPN. The presence of crosslinking in both phases of an IPN enhances the mutual miscibility of the polymers. Through the use of a labile crosslinker, acrylic acid anhydride (AAA), polymer networks may be decross-linked, allowing the chains to separate and form two distinct phases. Annealing further sharpens the transitions, and phase separation becomes most pronounced when decrosslinking is followed by annealing.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760261104
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of grafting on phase volume fraction, composition, and mechanical behavior: Epoxy/poly (n-butyl acrylate) simultaneous interpenetrating networks (1979)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 19 (1979), S. 297-303 
    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: Grafted simultaneous interpenetrating polymer networks (SINs) were prepared from Epon 828 epoxy resin and n-butyl acrylate monomer. The amount of grafting monomer (glycidyl methacrylate) was found to effect profound changes in the morphology and mechanical behavior of these materials. While the size of the dispersed rubbery phase increased from approximately 2 microns to 20 microns, the number of domains decreased, with increasing amounts of grafting agent. The total dispersed phase volume decreased with increased grafting. At the highest level of grafting, the two-phase morphology disappeared, and only one phase was observed. With increased grafting, dynamic mechanical spectroscopy showed a movement of the loss modulus peaks toward each other, confirming an increase in compatibility in the system and showing that the compositions in each phase were becoming more alike. The SIN with the most glycidyl methacrylate (3.0 percent) showed only one peak in the loss modulus curve, supporting the single phase morphology found through microscopy. At the point of compatibility between the two networks, the SIN supermolecular structure may be visualized as becoming one complex network, where the number of grafts between the two polymer chains outnumbers the number of homopolymer crosslinks. The chemical grafts were also shown to significantly alter the free energy of mixing of the two polymers. A grafting level-composition phase diagram showed that at well defined levels of grafting the free energy of mixing goes from a positive value to a negative value.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760190412
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  • 8
    Electronic Resource
    Electronic Resource
    Crosslinking of fluorocarbon elastomers: Characterization of crosslinking system to obtain transparent, tough materials (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 478-483 
    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: Viton® GLT is a new low-temperature fluoroelastomer with a Tg near -40°C. A study was made on methods of Crosslinking this material while retaining its transparency. Combinations of trimethylolpropane trimethacrylate, TMPTM, and triallyl isocyanurate, Diak® #7, were milled into Viton GLT. After molding, the materials were exposed to electron-irradiation, cross-linking the material. Transparent, tough materials were obtained for compositions containing about 3 percent TMPTM/3 percent Diak #7/3 Mrads, which had an extension of over 100 percent, a tensile strength of over 1000 PSI, excellent clarity, and low surface tack.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220805
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  • 9
    Electronic Resource
    Electronic Resource
    Introductory remarks - a symposium with a purpose (1977)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 17 (1977), S. 281-281 
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760170502
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  • 10
    Electronic Resource
    Electronic Resource
    Castor oil based interpenetrating polymer networks, IV. Mechanical behavior (1977)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 17 (1977), S. 251-256 
    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: The physical and mechanical properties of interpenetrating polymer networks (IPN's) based on castor oil-urethane and polystyrene are detailed in this paper. Dynamic mechanical spectroscopy showed extensive but incomplete molecular mixing of the two polymers. The glass transition temperatures of the IPN's gradually merged from two distinct transitions into one broad transition at an intermediate temperature as the crosslink level of the castor oil component was increased. At low polystyrene contents, the IPN's yielded stress-strain behavior similar to reinforced elastomers, but at high polystyrene contents, they exhibited increased elongation. For example, the latter materials showed well developed yield points. Stress whitening and necking were also observed, suggesting a possible failure mechanism by crazing. Cold drawing was exhibited by the materials under tension. The tensile strength and Young's modules were enhanced as the polymer II (polystyrene) content was increased at constant crosslink level of polymer I (castor oil-urethane). A similar effect was also observed by maintaining the polystyrene content constant but increasing the crosslink level of polymer I. The impact strength of the materials ranged from 32.1 to 53.4 N · m/m, which is approximately two to three times that of homopolymer polystyrene. The best materials were those with compositions in the range of 40-46 percent castor oil-urethane. The materials prepared by using tolylene diisocyanate as crosslinker for the castor oil phase had the best impact properties, especially at an NCO/OH ratio of 0.95.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760170408
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