Microheterogeneity and Structure Formation in Amorphous Polyurethane Block Copolymers (O Yavleniyakh Mikrogeterogennosti i Strukturoobrazovaniya v Amorfnykh Poluretanovykh Blok-Sopolimerakh),
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The authors have shown in their earlier work 1 that crystallization of at least one block components of a copolymer changes some properties of the whole copolymer. For example, the glass transition temperature Tc of one component could decrease in the course of crystallization the Tc of another component which is characterized by much lower Tc. The observed phenomenon was explained by a concentration of homogeneous blocks in microvolumes, i.e., an appearance of the microheterogeneity in block copolymers during crystallization. A division of the block copolymer components into microregions was also observed among amorphous copolymers, with components markedly different with respect to polarity 2. It could be expected that appearance and development of the microheterogeneity in similar systems would produce characteristic changes in thermomechanical properties. In this work amorphous block copolymers consisting of polyethylene adipate and polypropylene phthalate, crosslinked with OCNCH26NCO.
- Polymer Chemistry