NOVEL BLENDS OF HYPERBRANCHED POLYESTERS AND LINEAR-POLYMERS

A survey of the phase behavior of blends of hydroxyphenyl- and acetoxyphenyl-terminated hyperbranched polyesters with linear polymers such as polycarbonate, polyesters, and polyamides was carried out. For comparison, blends of poly(acetoxystyrene) (PAS) and poly(vinylphenol) (PVPh) and pairwise combinations of these and the two hyperbranched polyesters were studied. The hydroxy-terminated hyperbranched polyester blend miscibility was identical to that of poly(vinylphenol); this suggests that strong interactions due to hydrogen bonding, more so than chain architecture, dominate the blend miscibility. The acetoxy-terminated hyperbranched polyester showed less miscibility than those hydroxy-terminated polymers due to the absence of strong interactions but still more miscibility than the linear PAS. None of the blends of linear PVPh or PAS with hyperbranched polymer was miscible. However, homogeneous blends of PAS with PVPh and of the two hyperbranched polyesters were observed. In addition, a blend of linear Bisphenol A polycarbonate (PC) with an all-aromatic hyperbranched polyester resulted in increased tensile and compressive moduli and decreased strain-to-break and toughness compared to those of PC.