Modified poly(butylene terephthalate)–poly(tetramethylene glycol) multiblock copolymers were prepared by including either siloxane or silane units within the terephthalate hard blocks or the glycol soft blocks. These materials were characterized in terms of their dynamicmechanical properties, glass transition temperatures Tg, and morphology (as obtained from small-angle X-ray scattering measurements). One interesting result was the finding that putting siloxane units into the terephthalate hard blocks significantly decreased the storage modulus, whereas placing them into the glycol soft blocks somewhat increased it. Other interesting results were the observation that the Tg of the soft segments increased if the siloxane units were placed into the hard blocks but slightly decreased if they were placed into the soft blocks, while the hard-segment Tg was not observed at all. Some of these results could be explained in terms of the phase separation suggested by the X-ray scattering results.
Посилання на статтю:
Some block copolymers illustrating the effects of siloxane and silane units on the properties of terephthalate–glycol thermoplastics / Z. Pu, J.E. Mark, Z. Li, J. Zhu // Polymer. – 1999. – N 40. – P. 4695–4701.