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  • 1
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The diffusion of a fluorinated hydrocarbon into 30 keV-H+ irradiated glassy poly(styrene) (PS) was studied by using nuclear resonance reaction analysis. The diffraction coefficient and front velocity for diffusing a particular fluorinated hydrocarbon, 3, 5-bis (trifluoromethyl) aniline (TFMA) in PS (MW=400 000) are dramatically decreased on irradiation with 5×1013–1×1014 atoms/cm2 at 22.5 °C. These ion beam irradiation effects are similar to temperature effects on diffusion. A possible application of the observed effect is the control of diffusion of a vapor into cross-linked polymer glasses by means of ion beam implantation techniques. It is our belief that this is the first report of this phenomena due to the effects of ion beam irradiation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    ISSN: 0887-624X
    Keywords: interpenetrating polymer networks ; density ; equilibrium degree ; kinetics of solvent swelling ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have studied the densities, kinetics, and equilibrium degree of swelling in a number of different solvents of poly(carbonate urethane)/poly(methyl methacrylate) and poly(carbonate urethane)/poly(vinyl pyridine) interpenetrating polymer networks (IPN's). The kinetics of solvent uptake are often anomalous. The equilibrium extent of swelling reflects, among other factors, the number of phases present. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    ISSN: 0887-624X
    Keywords: pseudo-IPN ; chain molar mass dependence of morphology ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pseudo-IPN's of PCU/PS with different Mn and narrow MWD of the linear PS have been synthesized and characterized. The effect of Mn and composition on the phase morphology of the pseudo-IPN's of PCU/PS has been studied by DSC and SEM. The pseudo-IPN's with ultra-high Mn of the linear PS appeared to possess a single Tg and no SEM-resolvable domains at 35 wt % PS and below. This metastable state may reflect the result of a high extent of entanglement of the linear PS chains with the PCU network and the limited molecular mobility of the linear PS chains with high Mn. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 4
    ISSN: 0887-624X
    Keywords: phase morphology ; IPN ; pseudo-IPN ; PMMA ; PCU ; PVP ; PS ; deuterated PMMA ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 25 (1985), S. 32-36 
    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: Interesting phenomena were observed in the polymerization of styrene and ethylene oxide into PEO-PSt-PEO triblock copolymers using potassium naphthalene as initiator and tolusene as a solvent. The relationship between the phenomena and molecular weight of the blocks was studied. The purified and characterized triblock copolymer showed mesomorphic behavior in toluene solution which depolarized polarized light increasingly as the concentration was increased. The structure of the triblock copolymer was also studied by small-angle laser light scattering and by electron microscopy.
    Additional Material: 6 Ill.
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  • 6
    ISSN: 0887-624X
    Keywords: interpenetrating polymer networks ; poly(dimethylsiloxane-urethane) ; poly(methyl methacrylate) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simultaneous IPNs of poly(dimethyl siloxane-urethane) (PDMSU)/poly(methyl methacrylate) (PMMA) and related isomers have been prepared by using new oligomers of bis(β-hydroxyethoxymethyl)poly(dimethyl siloxane)s (PDMS diols) and new crosslinkers biuret triisocyanate (BTI) and tris(β-hydroxylethoxymethyl dimethylsiloxy) phenylsilane (Si-triol). Their phase morphology have been characterized by DSC and SEM. The SEM phase domain size is decreased by increasing crosslink density of the PDMSU network. A single phase IPN of PDMSU/PMMA can be made at an Mc = 1000 and 80 wt % of PDMSU. All of the pseudo- or semi-IPNs and blends of PDMSU and PMMA were phase separated with phase domain sizes ranging from 0.2 to several micrometers. The full IPNs of PDMSU/PMMA have better thermal resistance compared to the blends of linear PDMSU and linear PMMA. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    ISSN: 0887-624X
    Keywords: networks ; conjugation ; ionomers ; polyacetylenes ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An interpenetrating polymer network (IPN) based on poly(N-butyl 2-ethynylpyridinum bromide) (PB2EPB) and polycarbonate-urethane (PCU) has been prepared and characterized. The simultaneous full IPNs of PCU and PB2EPB have two glass transition temperatures corresponding to those of the linear chain blends measured by DSC. This suggests immiscibility of the two networks in the IPNs. The IPNs display a multiphase morphology which is confirmed by SEM observation. The full IPNs exhibit excellent solvent resistance, good thermal stability and good mechanical properties. High UV absorption of these materials extending to the visible range and beyond indicates that the polyacetylene network is extensively conjugated. The electrical conductivity of the IPNs increases linearly with increasing polyacetylene content reaching 10-4 S/cm. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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  • 8
    ISSN: 0887-624X
    Keywords: interpenetrating polymer networks ; poly(urethane carbonate) ; polyvinyl pyridine ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simultaneous interpenetrating polymer networks (IPN's), pseudo IPN's, and liner blends of aliphatic poly(carbonate-urethane) (PCU) and polyvinyl pyridine (PVP) have been prepared and characterized by DSC, DMA, and TEM. The full IPN's of PCU and PVP had a single phase morphology only above 50 wt % PCU, as determined by both DSC and DMA and confirmed by transmission electron microscopy (TEM). However, in both pseudo IPN's of PCU and PVP and in their linear blends there exist multiple glass transitions and melting points seen by DSC and DMA indicating phase incompatibility. The full IPN's exhibited superior ultimate mechanical properties and solvent resistance as compared to the pseudo IPN's, liner blends, and the pure crosslinked PCU and PVP networks.
    Additional Material: 9 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    ISSN: 0887-624X
    Keywords: IPN's ; poly(urethane carbonate) ; polystyrene ; mechanical and thermal properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simultaneous two-component interpenetrating polymer networks (IPN's), pseudo IPN's, and linear blends of urethane-containing aliphatic polycarbonate (PCU) and polystyrene (PS) have been synthesized and characterized. The simultaneous full IPN's of PCU and PS had one Tg only at compositions above 50 wt % PCU, as determined by DSC and DMA. The single phase morphology in the one Tg region was confirmed by transmission electron microscopy (TEM). However, the pseudo IPN's and linear blends of PCU and PS exhibited multiple (melting and glass) transitions by DSC measurements and phase separation was observed by TEM over the whole composition range. The full IPN's exhibited a maximum in ultimate mechanical properties at an intermediate composition. Superior solvent resistance as well as better thermal stability was shown by the IPN's as compared to the pseudo IPN's linear blends, and pure crosslinked components.
    Additional Material: 7 Ill.
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  • 10
    ISSN: 0887-624X
    Keywords: graft copolymer ; fully gelled networks ; polycarbonate urethane/PMMA ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have synthesized and characterized the graft copolymer of polymethyl methacrylate (PMMA)-graft-polycarbonate urethane (PCU) (designated PMMA-g-PCU) and the fully gelled mutually crosslinked network composed of both PMMA and PCU (designated as PMMA-PCU-N). Unlike the previously synthesized one phase PCU/PMMA simultaneous interpenetrating polymer networks (IPN's), both of these new materials exhibited two distinct Tg's (from DSC and DMA studies) at all compositions which we have studied. The two-phase nature of the graft and network polymer was confirmed by TEM with domain sizes smaller than those found in the blends of the linear PCU and PMMA chains. In comparison with the corresponding IPN's, the PMMA-g-PCU and the PMMA-PCU-N were thermally less stable and had a lower ultimate strength. © 1992 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
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