Brittle-ductile transition of gamma-irradiated recycled polyethylenes blend

During the last few years interest in the development of new engineering ma terials from post-consumer polyolefins present in discarded commercial pack aging has increased. These materials can be used as potential substitutes f or products made from non-renewable, synthetic polymers. Our Institute has developed several such materials with good properties using plastic residue s found in urban waste. One of these materials is a recycled 75/25 blend of outdoors, partially degraded low density polyethylene (LDPE) and high dens ity polyethylene (HDPE). The exposure of this blend to low doses of Co-60 g amma-radiation improves its compression strength as a result of partial cro sslinking. In this work the brittle-ductile transition temperature (BDTT) o f this recycled blend was evaluated after exposure to gamma-radiation (100 and 500 kGy) in the presence of air. The experimental results show that the BDTT changes with the irradiation doses. The higher doses cause an increas e in the Charpy impact values and a decrease in the BDTT. Gel permeation ch romatography, mechanical tests and scanning electron microscopy were used t o investigate these effects in the polymer material. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.