几种光敏降解聚乙烯薄膜的户外降解特性

The Degrading Behaviour of Photodegradable Polyethylene Films in Out-door Exposure

用红外光谱法,分子量测定和力学性能测定研究了几种国内外生产的光敏降解聚乙烯薄膜在自然气候曝露时的化学—物理变化。建立了羰基生成,链端乙烯基增长或分子量下降与入射试样表面的太阳紫外光剂量的相关关系。发现曝露薄膜的降解具有季节性。

During the outdoor weathering of photodegradable PE films and its changes inchemical constitution and mechanical property have been examined and inve-stigated by means of infrared spectroscopy,molecular weight determination a-nd tensile strength and elongation measurements.It established the relationshipbetween the content of carbonyl group or the increment of terminal vinyl gro-up or the viscosity-average molecular weight and the solar UV intensity irra-diated upon the surface of exposed films.It was found that the degrading rateof photodegradable PE films exposed outdoors varied with the season,althoughthe rate was defined on the UV intensify rather than the time in days,and itwas due to the quantum yield of photodegradation by photooxidation which isdependent on other climatic features also.