Exotherm Due to the Necking of Polyethylene Film

Abstract

The temperature rise of high density polyethylene films during necking was measured with a thermocouple and the generated heat was estimated. The fractions of mechanical work converted into heat were estimated to be 60-86% from the temperatures immediately after necking, and to be 67-90% from the maximum temperatures. Real films showed the fractions lower than 75% because of heat loss and of the formation of new surfaces like cracks. The fraction of heat conversion depended on film thickness, and thin films showed the higher values because of those larger neck propagation speeds. © 1993, The Society of Fiber Science and Technology, Japan. All rights reserved.