Copolyesters with Different Hard and Soft Segments

1 Copolyesters with Different Hard and Soft Segments 

It is generally accepted that the structure and the chemical composition of polyester hard segments have influence on the rate of synthesis, molecular weight, crystallization rate, elastic recovery, as well as tensile and tear strength. The hard segments structure affects primarily mechanical and processing properties, while the structure of the soft segments influences physical and chemical properties. It is known that the poly(ether ester)s 

The chemical structure, chain length and content of the soft segments primarily control physical and chemical properties of thermoplastic copolyester elastomers, such as resistance to heat, light, oxygen and water, as well as low temperature properties and tear strength, but have less influence on melting temperatures, hardness and modulus. 

Polyether Soft Segments. Polyftetramethylene oxide), polyfethylene oxide) and polyfpropylene oxide) and their random and block copolymers are most often used as soft segments. 

PTMO is used as a flexible segment in most of the commercial TPEEs. The PTMO segments with molecular weight higher than 1500 g/mol have tendency to crystallize causing a decrease 

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