光降解性聚乙烯薄膜降解过程的表征

Characterization of Photodegradable Low Density Polyethylene Films during the Photooxidation

用全反射傅里叶红外光谱（ＡＴＲ－ＦＴＩＲ）、Ｘ射线光电子能谱（ＸＰＳ）和示差扫描量热仪（ＤＳＣ）研究了含光敏剂的低密度聚乙烯（ＬＤＰＥ）薄膜在光降解过程中降解速率的变化规律。结果表明，光降解性聚乙烯薄膜在降解过程初期，降解速率很小，光敏剂显示抗氧化剂性能；降解２４ｈ后，降解速率迅速增加，直至薄膜破坏，光敏剂显示光引发剂性能。作为对比，同时研究了光敏剂和其它两种添加剂对聚乙烯薄膜光降解速率的协同效应和两种添加剂体系显示的性能。

The changes of the degradation ratio of the photodegradable low density polyethylene(LDPE)films containned a photosensitive additive(iron-dimethyldithiocarbamate)during the photooxidation have been examined by means of Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy( ATR-FTIR),X-ray Photoelectron Spectroscopy( XPS)and Differential Scanning Calorimeter( DSC).The degradation ratio has been indicated with changes of carbonyl index,Ols/Cls ratio and crystallinity.It has been show that the degradation ratio of the photod egradable LDPE film was initially very small,but was be ca me large after photooxidation for 24 h under the test condition. The performance of the photosensitive additive in LDPE film was initially antioxidant,but isconverted to photo-initiator by ultra-violet light correspondingly. Effect of the photosensitive additive in cooperation with carbon black or nickel-dibutyldithio-carbamate on degradation ratio of LDPE films has been studied simultaneously.