论文部分内容阅读
以聚丙烯酸(PAA)接枝改性的纳米TiO2作为光催化助氧化剂,与低密度聚乙烯(LDPE)复合制备了一种可光氧化-生物降解的TiO2-g-PAA/LDPE复合薄膜。通过失重率、红外光谱、扫描电镜、高温凝胶渗透色谱等分析研究了该复合薄膜在空气中紫外光照下的光氧化性能,并对预氧化降解后的薄膜进行了微生物的降解实验。结果表明,PAA接枝改性可以提高TiO2在薄膜内部的亲水性及分散性,提高TiO2的光催化活性,有利于促进LDPE薄膜的光氧化-生物降解;扫描电镜结果显示,TiO2-g-PAA/LDPE复合薄膜光催化反应不但发生在薄膜的表面,而且能够发生在薄膜内部,使其结构整体降解,其降解效果要优于TiO2/LDPE薄膜。紫外光照415 h后,TiO2-g-PAA/LDPE复合薄膜的失重率达到39.13%,重均相对分子质量下降96.36%;而相同条件下纯LDPE薄膜的失重率只有0.15%,重均相对分子质量下降46.32%。预氧化后的薄膜碎片具有明显的生物降解性能。
A photo-oxidizable-biodegradable TiO2-g-PAA / LDPE composite film was prepared by compounding with low density polyethylene (LDPE) with nano-TiO2 grafted with polyacrylic acid (PAA) as photocatalytic oxidant. The photooxidation performance of the composite films under UV light irradiation was investigated by weight loss, infrared spectroscopy, scanning electron microscopy and high temperature gel permeation chromatography. The degradation of the films was also studied. The results showed that the grafting modification of PAA could improve the hydrophilicity and dispersibility of TiO2 in the film, improve the photocatalytic activity of TiO2, and promote the photooxidation-biodegradation of LDPE film. The results of scanning electron microscopy showed that TiO2-g- The photocatalytic reaction of PAA / LDPE composite film not only occurred on the surface of the film, but also occurred in the interior of the film, resulting in the overall degradation of the structure. The degradation effect of PAA / LDPE film was better than that of TiO2 / LDPE film. The weight loss rate of TiO2-g-PAA / LDPE composite film reached 39.13% and the weight-average molecular weight decreased by 96.36% after 415 h UV light irradiation. Under the same conditions, the weight loss rate of pure LDPE film was only 0.15% Down 46.32%. Pre-oxidized film fragments have significant biodegradability.