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Comparison of glass transition and interpretation on miscibility in blends of amorphous poly(vinyl methyl ether) with highly crystallizable versus less-crystallizable polyesters Part B Polymer physics
- Chiang, Wan-Jing, Woo, E.M.
- Journal of polymer science 2007 v.45 no.20 pp. 2899-2911
- crystal structure, differential scanning calorimetry, glass transition, microscopy, physics, polyesters
- Various phase behavior of blends of poly(vinyl ether)s with polyesters of two types (highly crystalline and less crystalline with different main-chains) were examined using differential scanning calorimetry (DSC) and optical microscopy (OM). Effects of varying the main-chain polarity of the constituent polyesters on the phase behavior of the blends were analyzed. Miscibility in PVME/polyester blends was found only in polyesters with backbone CH₂/CO ratio = 3.5 to 7.0). Tg-composition relationships for blends of PVME with highly crystalline polyesters (PBA, PHS) were found to differ significantly from those for PVME blends with less-crystalline polyesters (PTA, PEAz). Crystallinity of highly crystalline polyester constituents in blends caused significant asymmetry in the Tg-composition relationships, and induced positive deviation of blends' Tg above linearity; on the other hand, blends of PVME with less crystalline polyesters exhibit typical Fox or Gordon-Taylor types of relationships. The χ parameters for the miscible blends were found to range from -0.17 to -0.33, reflecting generally weak interactions. Phase behavior was analyzed and compared among blends of PVME with rapidly crystallizing vs. less-crystallizing polyesters, respectively. Effects of polyesters' crystallinity and structures on phase behavior of PVME/polyester blends are discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2899-2911, 2007