Browsing by Author "SUBRAMANIAN, N"

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    GAS-PERMEABILITY STUDIES ON POLY(VINYL CHLORIDE) BASED POLYMER BLENDS INTENDED FOR MEDICAL APPLICATIONS
    (JOURNAL OF APPLIED POLYMER SCIENCE, 1992) PAL, SN; RAMANI, AV; SUBRAMANIAN, N
    Plasticized PVC finds applications in a wide range of medical products. However, plasticizer leaching, known to take place from these conventional materials, is not desirable. A number of approaches to overcome this problem are mentioned in the literature. We suggest pursuing the polyblend approach. Plasticized PVC containing different amounts of plasticizer, binary polyblends of plasticized PVC (PPVC) with acrylonitrile-butadiene rubber (NBR1), and compounded graft polymer of vinyl chloride and ethylene-vinyl acetate copolymer (EVAPVC), and ternary blends of PPVC, NBR1, and EVAPVC, were formulated. In this article, we report our results of studies on water vapor, O2, CO2, and N2 permeabilities. Increased plasticization for PVC was found to increase permeability for water vapor, O2, CO2, and N2. Rise in temperature increased the permeability for water vapor and the change became faster as the materials crossed the region of T(g). A simple model suggested for permeability worked satisfactorily. The binary and ternary blends, based on PPVC, had lower O2, CO2, and N2 permeability. This improvement in property is of great practical significance and interest and the results indicate that PVC-based polyblends can be investigated further for potential applications in medicine.
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    STUDIES ON POLY(VINYLCHLORIDE)-BASED POLYMER BLENDS INTENDED FOR MEDICAL APPLICATIONS .2. MECHANICAL-PROPERTIES
    (POLYMER ENGINEERING AND SCIENCE, 1992) PAL, SN; RAMANI, AV; SUBRAMANIAN, N
    Binary polyblends of plasticized poly(vinylchloride) (PPVC1) with acrylonitrile-butadiene rubber (NBR1), compounded graft polymer of vinyl chloride and ethylene-vinyl acetate copolymer (EVAPVC) and ternary blends of PPVC1, NBR1, and EVAPVC were formulated to study mechanical proper-ties. For the "pure" components, elongation at break was found to be in the order PPVC1 < EVAPVC < NBR1. Addition of both EVAPVC and NBR1 resulted in improvement of ultimate elongation and tensile energy to break. PPVC1-NBR1 binary blends exhibited synergistic behavior for both ultimate tensile stress and elongation at break, indicating the presence of appreciable specific interactions between the polymers. About 30% replacement of PPVC1 by NBR1 or EVAPVC resulted in marginal fall in modulus and significant improvement in elongation at break. EVAPVC or blends containing EVAPVC had a tendency to creep. A simple generalized equation suggested for various mechanical properties works satisfactorily. The results obtained have practical implications and indicate that PVC-based polyblends can be investigated further for potential applications in medicine.