Morphology of PC/SAN blends: effect of reactive compatibilization, SAN concentration, processing, and viscosity ratio

Abstract

This article examines the effects of dispersed phase concentration, processing apparatus, viscosity ratio, and interfacial compatibilization using an SAN–amine compatibilizer on the morphology of blends of bisphenol A–polycarbonate (PC) with styrene–acrylonitrile (SAN) copolymers. For uncompatibilized blends, the dispersed phase particle size increased significantly with SAN concentration, and was found to exhibit a minimum at a viscosity ratio of approximately 0.35 for a fixed concentration of 30% SAN in the blend. Although the morphology of uncompatibilized PC/SAN blends mixed in a Brabender mixer, single‐ and twin‐screw extruders were quite similar, the twin‐screw extruder produced significantly finer morphologies in blends containing SAN–amine. The average particle size for blends compatibilized with the SAN–amine polymer was approximately half that of uncompatibilized blends and was relatively independent of viscosity ratio and dispersed phase composition. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 71–82, 1999

Effects of mixing protocol on morphology and properties of PA6/ABS blends compatibilized with MMA‐MA

“…It has been extensively shown that presence of conveniently chosen polymeric species, normally functionalized copolymers, leads to a reduction in dispersed particle size. This reduction is mainly attributed to the efficiency of these copolymers in promoting steric stabilization of second phase, suppressing the coalescence phenomena . Furthermore, an effective compatibilizer system also improves the adhesion between phases, resulting in superior mechanical properties …”

Effect of reactive compatibilization on the properties of poly(butylene terephthalate)/acrylonitrile–ethylene–propylene–diene–styrene blends

“…It has been extensively shown that the presence of adequate copolymers at the interface of immiscible blends promotes a decrease in the disperse particle size, mainly because of the efficiency of these copolymers in promoting a steric stabilization of the particles, leading to a suppression of the coalescence phenomena 38–43. Moreover, it has also been shown that there should be a minimum concentration of these copolymers at the particle surface for this suppression to become effective.…”

Compatibilization of polymer blends from poly(styrene‐co‐acrylonitrile) and polycarbonate by oxazoline modification of poly(styrene‐co‐acrylonitrile) in the melt

“…Because of their economic importance, blends of S/AN and PC have recently drawn a lot of scientific attention. The multifaceted field of applications for these blends runs from the automotive and electronic industries to multilayer systems 1–13. Blends of S/AN and PC are immiscible under normal conditions 14–17.…”

“…Despite their immiscibility, unmodified blends of S/AN and PC are among the most successful multiphase materials in the automotive and electronic industries 1–6. The main problem of S/AN–PC blends is their tendency to coalesce during processing, which can result in coarse structures and inferior material properties 8–12. Even short downtimes at a processing temperature of 270°C (e.g., in injection‐molding machines) can cause a significant deterioration of the morphology 32.…”

“…A good strategy for lowering the surface tension between two polymers is the in situ introduction of chemical bonds between the two phases 33. There have been several attempts to stabilize S/AN–PC blends, mainly with block copolymers of PC and poly(methyl methacrylate),25 terpolymers of methacrylate, butadiene, and styrene,33 or terpolymers of styrene, amine‐functionalized maleic anhydride, and AN 11, 12, 34. Even modified PC,35 aliphatic polyesters, and polyamide 6 (PA‐6)36–38 have been used to compatibilize S/AN–PC blends.…”