Impact modification of styrene-acrylonitrile copolymers by methyl methacrylate grafted rubbers

✍ Scribed by H. Keskkula; H. Kim; D. R. Paul

• Publisher: Society for Plastic Engineers
• Year: 1990
• Tongue: English
• Weight: 929 KB
• Volume: 30
• Category: Article
• ISSN: 0032-3888
• DOI: 10.1002/pen.760302107

✦ Synopsis

Abstract

Monodisperse methyl methacrylate grafted latex rubber (MMA‐g) particles (0.12‐0.13 µm) have been used for the impact toughening of a series of styrene‐acrylonitrile (SAN) copolymers of varied AN content. It was found that the MMA‐g particles are most effective in toughening SANs containing about 25 to 34% AN. Mechanical properties, interphase adhesion, mechanical dilatometry, and phase morphology by transmission electron microscopy were determined on blends containing 20‐30% rubber. Also, the miscibility range of SANs and poly(methyl methacrylate) (PMMA) graft was considered in attempting to analyze the relationships between the mechanical properties and the characteristic features of the blends. Issues relating the impact strength and deformation mechanisms, interphase adhesion, and particle morphology are discussed. It appears that the high impact strength of some of the blends may be caused primarily by certain morphological features such as particle clustering or small interparticle distances. Thus, craze initiation, shear yielding, and significant matrix deformation may all contribute to the overall ductility of the blend.