Weathering of noncrystalline polymers in an extreme climate
Authors:
White J R Qayyum M M
Issue Date:
1988
Citation:
Weathering of noncrystalline polymers in an extreme climate M M Qayyum and J R WhiteThe Arabian journal for science and engineering المجلة العربية للعلوم والهندسة Univeristy of Petroleum and MineralsVol 13 no 4 (October 1988) p p 545556Qayyum M MWhite J R
Abstract:
تم تعريض قضبان بلاستيكية مصنوعة بطريق الحقن من البولي كربونات (PC) والبولي ميثيل ميثكريلات (PMMA) والبوليستيرين (PS) والبولي فينيل كلوريد (PVC) للظروف الجوية الخارجية في مدينة جدة من المملكة العربية السعودية وتراوحت مدة التعريض لمدى خمس سنوات وهذا البحث يناقش تأثير عملية التفكك بفعل عوامل التعرية على الخواص الفيزيائية والكيميائية لهذه المواد Injection moulded bars made from polycarbonate (PC) poly (methyl methacrylate) (PMMA) polystyrene (PS) high impact polystyrene (HIPS) and poly (vinyl chloride) (PVC) have been weathered outdoors in Jeddah Saudi Arabia for periods up to five years The residual stresses present in the asmoulded bars reduced on weathering and with PS HIPS and PVC reversed in sense to become tensile near the surface and compressive in the interior All weathered samples failed in uniaxial tension by fracture nucleated at the surface PC and PVC displayed a ductile fracture mode with diamondshaped fractures starting in the embrittled surface and growing into the underlying material in a controlled fashion Links between the physical changes that take place on weathering and chemical changes that lead to reduction in molecular weight and glass transition temperature are discussed
