Poly(styrene-ran-cinnamic acid) (SCA), an approach to modified polystyrene with enhanced impact toughness, heat resistance and melt strength.

Jie Wang,Xinghou Gong,Tao Hu,Dachuan Ding,Xuan Zheng,Ying Chang,Peihua Li,Zixin Yu,Chonggang Wu,Chuanqun Hu

doi:10.1039/c9ra08635h

Abstract

A poly(styrene-ran-cinnamic acid) (SCA) containing 6.8 mol% of CA, with a M̄w (∼217 000) comparable to commercial polystyrene (PS), was successfully synthesised via emulsion free-radical copolymerisation as evidenced by 1744 and 1703 cm−1 infrared peak occurrences, respectively characteristic of free and dimeric carboxyl C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> O stretches. Upon the interchain hydrogen bond cross-linking by CA, the impact toughness of the SCA was considerably improved by 47.2% against PS, the glass transition, heat deflection and Vicat softening temperatures were significantly enhanced until 117.0, 108.0 and 118.3 °C, respectively, compared with PS (95.2, 87.6 and 96.0 °C), while the extensional viscosities were near one order-of-magnitude higher than PS by which the temperature window required for appropriate melt-strengths would be greatly broadened. Meanwhile, the SCA displayed other properties basically analogous to PS. This work presents a modified PS, SCA, with enhanced toughness, heat resistance and melt strength that potentially extend its styrofoam and commodity applications.

Highlights

Since its commercialisation, polystyrene (PS), a commodity resin second in consumption only to polyethylene and poly(vinyl chloride) (PVC), has widely been used in packaging materials, automotive interiors, electronic components, etc. because of its good transparency, high modulus, superior electrical insulation, satisfactory dyeability, low price and excellent processability
Owing to the presence of bulky, rigid pendant phenyl groups as well as weak, nonpolar chain-segmental interactions, PS exhibits poor toughness, i.e. high brittleness; PS does not have high enough heat resistance as well to extend itself to engineering applications, and more importantly, the low melt-strength of PS limits its foamability during styrofoam production
As a styrenic, the SCA is systematically characterised in terms of its mechanical, thermal, processing, dielectric, re and other physical properties, in which an emphasis is placed on the examination of its toughness, heat resistance and melt strength

Summary

Introduction

Polystyrene (PS), a commodity resin second in consumption only to polyethylene and poly(vinyl chloride) (PVC), has widely been used in packaging materials, automotive interiors, electronic components, etc. because of its good transparency, high modulus, superior electrical insulation, satisfactory dyeability, low price and excellent processability. The HDT values of the specimens were nally measured in accordance with the ISO 75 testing standard using a heat de ection and Vicat so ening temperatures tester (Shenzhen City Aode Saichuang Technology Co., Ltd., China, Auto-RBWK), during their heating in a methyl-silicone oil bath from 25 to 200 C at a rate of 120 C hÀ1.

Results

Conclusion