Ester block copolymers, elastomeric poly ether

The work reported here is concerned with the syntheses and properties of polyether-ester block copolymers containing poly (tetramethylene ether) units of molecular weight of approximately 1000 as the amorphous polyether blocks and a variety of esters as the crystallizable hard segments. The purpose of this study is to correlate changes in synthesis and properties of these thermoplastic and elastomeric copolymers with changes in the concentration and nature of the ester segments, particularly the types of diol and diacid. 

T nterest in polyether-ester block copolymers that are both thermoplastic - and elastomeric continues at a sustained pace (1-9). Most of the recent communications have dealt with the tetramethylene terephthalate/ poly(tetramethylene ether) terephthalate copolymers which are continuing to find increased use in commercial applications requiring thermoplastic elastomers with superior properties. 

Elastomeric polyether-ester block copolymers were prepared by melt transesterification of poly(tetramethylene ether) glycol of molecular weight approximately 1000 with a variety of diols and esters. The ease of synthesis and the properties of these thermoplastic copolymers have been related to the chemical structure and concentration of the ester hard segments. 

Because of their hydrophilic nature the 2G.T-POE group of block copolymers are unsuitable for use as structural substances but this very property has indicated their application as electrostatic charge dispersants in synthetic fibres and as potentially useful biodegradable surgical materials. Most attention has been devoted to the thermoplastic elastomeric group of random block poly(ether ester)s, notably those based on 4G.T (or 4G.T-co-isophthalate) as the hard block components and POTM terephthalate as the soft segments which have emerged as important commercial products. These copolymers combine ready processability with excellent mechanical... 

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