block copolymer
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elastomers
- In rubber: The rise of synthetic rubber
For example, block copolymers, in which a long sequence of one chemical unit is followed in the same molecule by a long sequence of another, were made, using many different units and sequence lengths. New oil-resistant and heat-resistant elastomers were introduced, including the styrene-acrylonitrile copolymers, the polysulfides,…
Read More - In elastomer: Block copolymers
Another type of intermolecular association is shown by thermoplastic block copolymers, where each molecule consists of long sequences, or blocks, of one unit followed by long sequences of another. Because different polymers are generally incompatible (i.e., do not dissolve into one another), blocks…
Read More - In copolyester elastomer
Copolyester elastomers are block copolymers—that is, the two different types of chemical repeating units that make up the chainlike molecules occur in long sequences, or blocks. The hard sequences usually consist of polybutylene terephthalate (PBT), a stiff polyester resin. The soft sequences consist of any one of a…
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