In situ compatibilization of polystyrene/ polyolefin elastomer blends by the Friedel-Crafts alkylation reaction

摘要

Blends of polystyrene (PS) with polyolefin elastomer (POE) were prepared by a reactive extrusion method.In order to increase the compatibility of the two blending components,a Lewis acid catalyst,aluminium chloride (AlCl_3),was adopted to initiate the Friedel-Crafts alkylation reaction.Fourier-transform infrared (FTIR) spectra of the PS/POE/AlCl_3 blends extracted with butanone verified the graft structure between the PS and POE.Because the in situ generated PS-graft-POE copolymers acted as compatibilizers,the mechanical properties of PS/POE blends were greatly improved.For example,after compatibilization,the Charpy impact strength of an 80/20 (wt%) PS/POE blend was increased from 6.29 to 8.50 kJ m~(-2).Scanning electron microscopy (SEM) showed that the size of the droplets decreased from 9-10 mum to less than 2 mum with the addition of AlCl_3.Gel permeation chromatography (GPC) showed competition between the grafting reaction and the degradation of blending components in the presence of AlCl_3.