The Structure and Mechanical Properties of Blends of Cis and Trans-Polyisoprene
A series of blends of cis/trans-polyisoprene (0–100%) show a single glass transition temperature and are compatible at all compositions. The crystallinity decreasing linearly with crystallizable trans content. All the blends show impinged spherulites even at crystallinities of 1 to 2%. The spherulite growth rate decreases as the non-crystallizable content of the blends increases. TEM observations show that the crystals within spherulites become more branched and dentrite like at low crystallinities; fibrils of crystals are seen larger non-crystalline spacings between the fibrils. The lamellar crystal thickness changes only slowly with crystallinity. The long period increases with decreasing crystallinity in the manner suggested by the TEM observations. The tensile modulus decreases with crystallinity and attempts have been made to describe the change with simple reinforcement theory.
KeywordsTensile Modulus Lamellar Thickness Trans Content Spherulitic Morphology Spherulite Growth Rate
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