NOVEL BLENDS OF HYPERBRANCHED POLYESTERS AND LINEAR-POLYMERS

A survey of the phase behavior of blends of hydroxyphenyl- and acetoxy phenyl-terminated hyperbranched polyesters with linear polymers such a s polycarbonate, polyesters, and polyamides was carried out. For compa rison, blends of poly(acetoxystyrene) (PAS) and poly(vinylphenol) (PVP h) and pairwise combinations of these and the two hyperbranched polyes ters were studied. The hydroxy-terminated hyperbranched polyester blen d miscibility was identical to that of poly(vinylphenol); this suggest s 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-ter minated polymers due to the absence of strong interactions but still m ore 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 o bserved. In addition, a blend of linear Bisphenol A polycarbonate (PC) with an all-aromatic hyperbranched polyester resulted in increased te nsile and compressive moduli and decreased strain-to-break and toughne ss compared to those of PC.