Quantitative image analysis of polymer blends

Abstract

Quantitative image analysis is important in understanding the role of microstructure in polymer blend properties, as revealed by the TEM. This paper presents an example of the application of the image analysis method to the study of structure/property relationship of an acrylonitrile-butadiene-styrene (ABS) polymer.ABS is a rubber-toughened two-phase polymer blend. As shown in Figure 1, the microstructure of ABSconsists of small rubber particles embedded in a styrene-acrylonitrile copolymer (SAN) matrix. The morphologies of these blends, which depend on the polymerization conditions, play a key role to the overall physical and mechanical properties of the blends. The quantitative characterization of the rubber phase involves measuring its volume fraction as well as the particle size distribution.Four ABS samples, available commercially, with different levels of styrene butadiene rubber (SBR),were used in this study. The samples were block stained, using osmium tctroxide (OsO4) solution, and thin sectioned in an ultramicrotome.The thin sections were examined in a JEM-100CX II TEM, operated at 60KV. The representative images were acquired on a SEMICAPS Imaging System using a GATAN CCD TV rate camera.