Polyethylene/Polystyrene grafting reaction. Effects of Polyethylene Molecular Weight

MÓNICA F. DIAZ; SILVIA E. BARBOSA; NUMA J. CAPIATI

POLYMER

Elsevier

Año: 2002 vol. 43 p. 4851 - 4858

0032-3861

Abstract Blending of different thermoplastic polymers usually results in segregated and low value materials for almost any mixing condition. Nevertheless, a synergetic combination of properties can be obtained by an adequate compatibilization via reactive blending. In this work a Friedel–Crafts alkylation reaction is used to graft polyethylene chains onto polystyrene. The relation between the initial PE molecular weight (MW) and the structure of the compatibilizer copolymer is studied by a combination of size exclusion chromatography and Fourier transforminfrared spectroscopy. The amount of copolymer formed is estimated from the amount of polystyrene reacted. The relative lengths of the grafted polyethylene chains are assessed. It is found that lower MWPE produces, upon reaction, a greater amount of short chain length grafted PE onto PS than higher MWPE. The results are in agreement with theories relating the component MW to the reaction localization at the interface. The low cost Friedel–Crafts alkylation results in a convenient reaction for the in situ compatibilization of PE/PS blends. It produces enough graft copolymer to compatibilize the phases without causing PS cross linking and PE chain scission.  2002 Elsevier Science Ltd. All rights reserved. Keywords: Reactive blending; PE/PS grafting; Compatibilization