FTIR AND DSC STUDY OF HDPE STRUCTURAL-CHANGES AND MECHANICAL-PROPERTIES VARIATION WHEN EXPOSED TO WEATHERING AGING DURING CANADIAN WINTER

The aging of high-density polyethylene (HDPE) when exposed to drastic climatic conditions (Canadian winter, characterized by low temperature and abrupt temperature variations between the night and the day) was studied. The importance of degradation was determined by evaluating th e microstructural changes in HDPE (i.e., oxidations, ramifications, an d polymeric chain breaking) by means of FTIR spectrophotometry. The cr ystallinity variation in HDPE by FTIR and DSC was also studied. Both t echniques led to coherent results: there was a loss of crystallinity d ue to weathering degradation. This crystallinity reduction produced a drastic decrease in impact energy. However, the other properties evalu ated were not significantly affected. (C) 1996 John Wiley & Sons, Inc.