Morphology Formation in PC/ABS Blends during Thermal Processing and the Effect of the Viscosity Ratio of Blend Partners

Abstract

Morphology formation during compounding, as well as injection molding of blends containing 60 wt % polycarbonate (PC) and 40 wt % polybutadiene rubber-modified styrene-acrylonitrile copolymers (ABS), has been investigated by transmission electron microscopy (TEM). Profiles of the blend morphology have been recorded in injection-molded specimens and significant morphology gradients observed between their skin and core. A <10 µm thick surface layer with strongly dispersed and elongated nano-scale (streak-like) styrene acrylonitrile (SAN) phases and well-dispersed, isolated SAN-grafted polybutadiene rubber particles is followed by a 50–150 µm thick skin layer in which polymer morphology is characterized by lamellar SAN/ABS phases. Thickness of these lamellae increases with the distance from the specimen’s surface. In the core of the specimens the SAN-grafted polybutadiene rubber particles are exclusively present within the SAN phases, which exhibit a much coarser and less oriented, dispersed morphology compared to the skin. The effects of the viscosity of the SAN in the PC/ABS blends on phase morphologies and correlations with fracture mechanics in tensile and impact tests were investigated, including scanning electron microscopy (SEM) assessment of the fracture surfaces. A model explaining the mechanisms of morphology formation during injection molding of PC/ABS blends is discussed.

Tuning gradient microstructures in immiscible polymer blends by viscosity ratio

“…The gradient structures in polymer blends originate mainly from the structural reformations of the processed material due to the gradient of the flow field in the capillary die . The development of radial and axial flow fields in a capillary are complex and largely determined by capillary length, diameter, and entrance angle .…”

“…27,29 The gradient structures in polymer blends originate mainly from the structural reformations of the processed material due to the gradient of the flow field in the capillary die. 19,36,37 The development of radial and axial flow fields in a capillary are complex and largely determined by capillary length, diameter, and entrance angle. 38,39 However, once the capillary geometry is fixed, the possibilities to tune the gradient structure are limited due to the fixed flow fields.…”

Relationship between the interfacial tension and compatibility of polycarbonate and poly(acrylonitrile–butadiene–styrene) blends with reactive compatibilizers

“…The blends of PC and PolyABS may satisfy both constituent polymer properties. For that reason, PC–PolyABS blends have been used in many ways, such as for automobile parts and electronic equipment . Although PC–PolyABS blends are basically immiscible, PC–PolyABS blends are being manufactured without compatibilizers.…”

Experimental design to enhance the surface appearance, the internal structure, and the shear stresses of injected and metallized polycarbonate/acrylonitrile–butadiene‐styrene parts

“…The main causes of these defects were mainly shortcomings in the electroplating parameters and the properties of the surface and subsurface structures of the injection‐molded parts. Indeed, despite the noticeable progress in improving the quality of PC/ABS products, which have attracted the consumers because of their esthetic presentation, lightweight, and cost effectiveness, industrialists are still dissatisfied because of high rate of rejection due to defects in the surfaces of the injection‐molded parts . The most frequently reported defects were scratch, weld line, blister, moisture streaks, poor adhesion, burn marks, sink marks, flow marks, and shrinkage .…”