Rheological Behavior of Polymer/Styrene Blends that Emulate a Bulk High-Impact Polystyrene Process

LUCIANI, C. V.; DIAZ DE LEÓN, R.; MORALES, G.; ESTENOZ, D. A.; MEIRA, G. R.

Los Cocos, Prov. de Córdoba, Argentina

Congreso; III Simposio Argentino-Chileno de Polímeros (Archipol’05); 2005

High-Impact Polystyrene (HIPS) is a heterogeneous material globally composed by around 80% of free polystyrene (PS), 18% of graft copolymer, and 2% of unreacted PB. The final HIPS properties are determined by the molecular structure of the 3 mentioned components and by the particle morphology (Okamoto et al., 1991; Choi et al., 2000). The HIPS morphology is basically determined during the phase inversion (Luciani et al., 2005). Thus, it is important to estimate when this phenomenon takes place. In spite of the importance of the phase inversion, no mathematical model has as yet been developed that is capable of determining when it occurs. Viscosity measurements of the reaction mixture have been used for experimentally determining the phase inversion period (Freeguard and Karmarkar, 1971; Soto et al., 2004). Zhiqiang et al. (1986) developed regression equations based on viscosity data of the emulated mixtures and their isolated phases. In this work, an experimental and theoretical study is presented for estimating the apparent viscosity of PS/PB/BC/St blends. This contribution must be considered is a first step toward the aim of theoretically estimating the phase inversion period along a bulk polymerization of St in the presence of a rubber.