Rheology of Immiscible Polymer Blends

Abstract The polymer industry has been challenged to produce new polymeric materials by blending two or more homopolymers or random copolymers or by synthesizing graft copolymers. To meet the challenge, various methods have been explored, namely, (1) by synthesizing a new monomer, polymerizing it, and then blending it with an existing homopolymer or random copolymer, (2) by copolymerizing existing monomers and then blending it with an existing homopolymer or random copolymer, (3) by chemically modifying an existing homopolymer or random copolymer and then blending it with other homopolymers or copolymers already available, or (4) by synthesizing new compatibilizer(s) to improve the mechanical properties of two immiscible homopolymers or random copolymers that otherwise have unacceptable mechanical properties. There are numerous monographs (Cooper and Estes 1979; Han 1984; Paul and Newman 1978; Platzer 1971, 1975; Sperling 1974; Utracki 1990) describing various aspects of polymer blends. In the 1970s, Han and coworkers (Han 1971, 1974; Han and Kim 1975; Han and Yu 1971a, 1971b, 1972; Han et al. 1973, 1975; Kim and Han 1976) conducted seminal experimental studies on the rheology of immiscible polymer blends and related the observed rheological behavior to blend morphology. Independently, in the same period, Vinogradov and coworkers (Ablazova et al. 1975; Brizitsky et al. 1978; Tsebrenko et al. 1974, 1976; Vinogradov et al. 1975) conducted a series of experimental studies relating the blend rheology to blend morphology. Van Oene (1972, 1978) also pursued, independently, experimental studies for a better understanding of rheology–morphology relationships in immiscible polymer blends. Since then, using different polymer pairs, numerous researchers have conducted experimental studies, which were essentially the same as, or very similar to, the previous experimental studies of Han and coworkers, Vinogradov and coworkers, and van Oene in the 1970s. It is fair to state that those studies in the 1980s and 1990s have not revealed any significant new findings.