Synthesis and characterization of high impact grade polystyrene nbased on EPDM elastomers

Author(s)

Emerson Lourenço

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2007-05-24

Examining board members

Maria Isabel Felisberti; Ana Maria Rocco; Cristina Moniz Araujo Lopes; Celso Aparecido Bertran; Celso Ulysses Davanzo

• Advisor: Maria Isabel Felisberti

Abstract

High impact polystyrene (HIPS) shows a wide range of application in automotive industry, however its utilization is restricted by the photooxidative degradation of the elastomeric phase that contains high degree of unsaturation. In this way, the aim of this work was to prepare and characterize in situ polymerized blends of polystyrene (PS) with saturated elastomers: poly(ethylene-co-propylene-co-2-ethylidene-5-norbomene) (EPDM) and poly(acrylonitrile-g-EPDM-g-styrene) (AES), aiming the preparation of a material with good mechanical properties and higher resistance to photodegradation. The blends were prepared by in situ polymerization at 60 °C and 80 °C. The PS/AES and PS/EPDM blends are immiscible. The non injected blends prepared in this work present a morphology that consists of PS or PS/SAN globes covered by a thin layer of EPDM for PS/EPDM and PS/AES blends, respectively. Whereas the injected blends show a morphology of elastomeric dispersed phase into a rigid matrix. The PS/AES and PS/EPDM show higher thermal and thermo-oxidative stability than PS, and the blend's composition and polymerization's temperature influences the degradation of these materials. The results showed in this work evidence the higher photochemical resistance PS/AES and PS/EPDM blends in comparison with commercial HIPS. An important feature of blends is that their properties after aging are superior than photoaged HIPS properties. Hence, the goal of preparing a material with higher resistance to photochemical aging than HIPS was achieved. (AU)