光/生物降解聚乙烯薄膜的光降解性能

Photo-Degradation Properties of Photo Biodegradable Polyethylene Films

采用傅里叶变换红外光谱（FTIR）、示差扫描量热（DSC）、凝胶渗透色谱（GPC）和气相色谱．质谱联用（GC-MS）等方法，研究了质量分数为35％的淀粉光／生物降解聚乙烯薄膜的光降解性能、产物结构及降解机理。结果表明，可通过光敏剂种类和用量调节薄膜的光降解速度。硬脂酸铁和硬脂酸铈的光敏化作用相近，均优于二乙基二硫代氨基甲酸铁；在光敏剂质量分数为0．2％-0．3％时制得的光／生物降解薄膜光降解性能较好。随着薄膜的光降解程度增大，羰基指数和薄膜中聚乙烯的结晶度升高，而熔点和相对分子质量下降。其光降解产物中含有低分子量的烷烃、酮、醛、酯、一元羧酸和二元羧酸等。

Photo-degradabilities, structures and degradati containing 35% of corn starch were investigated by using results show that the degradation rate could be regulated on principles of photo-biodegradable plastic films FTIR, DSC, GPC and GC-MS. The experiment through different sensitizer and its content. Iron stearic and cerium stearic have the same photosensitive action on the film, which is better than that of diethyl iron dithiocarbamate. A suitable sensitizer concentration is about 0. 2% -0. 3%. With increasing the degree of degradation, the carbonyl index and crystallinity of polyethylene in films increase, but the melting point and relative molecular weight of polyethylene in films decrease. Some low molecular weight products, such as alkyl hydrocarbon, ketone, aldehyde, ester, carboxylic acid and binary carboxylic acid were detected in the degraded films.