Poly(ether-block-sulfonated ester) copolymers. I. Phase structure and physical properties

The physical properties and a microphase-separated structure of multiblock copolymers based on flexible segments of poly(1,4-oxytetramethylene) (PTMO) and rigid crystalline segments of poly(butylene terephthalate) (PBT) modif ied by ionic units were studied. Ionic copolymers were characterized by lim iting viscosity number, melt flow index, and tensile property measurements. The mechanical behavior of ionic poly(ether-block-sulfonated ester) (PESE) copolymers can be compared to that of conventional hard-soft thermoplastic elastomers. The phase structure was studied using differential scanning ca lorimetry (DSC). Clearly, the DSC results show that the ionic units in the polyester segments have no significant influence on the microphase separati on structure of PESE. A small reduction of the degree of crystallinity with increasing content of ionic groups in the polyester rigid segments was obs erved. This results from the effect of ionic forces caused by incorporation of ionic units in the polyester segments.