Phase structure and compatibility of ladderlike polyphenylsilsesquioxane (PPSQ)/polycarbonate (PC) blends prepared by solution casting

Blends of PC and PPSQ (A) with high M-w and good ladderlike regularity or P PSQ(B) with low M-w and more defective Si-atoms in its structure have been prepared by solution casting. The dispersed spheres (PPSQ(A)-rich) are unev enly dispersed in the continuous PC-rich phase and there is no phase-invers ion as PPSQ(A) content increases when the percentage of PPSQ(A) is not more than 70%. PPSQ(B)-rich spheres are evenly dispersed in the continuous phas e (PC-rich) and phase-inversion occurs when PPSQ(B) percentage is up to 70% . T-g of PPSQ(A)/PC or PPSQ(B)/PC at some compositions are lower than that of pure PC due to the enlarged free-volume of PC-rich phase because some sp heres of rigid PPSQ chains are included in the PC-rich phase. PC and PPSQ(A ) or PPSQ(B) are partially compatible. The compatibility of PC and PPSQ(B) is better than that of PC and PPSQ(A) with high M-w and good ladderlike reg ularity. Heat history has some influence on the T(g)s and compatibility of PPSQ(A)/PC and PPSQ(B)/PC blends.