降解性聚乙烯地膜降解过程中力学性能和化学结构的变化

THE STUDY OF MECHANICAL PROPERTY AND CHEMICAL STRUCTURE CHANGES OF DEGRADABLE PE MULCH FILM DURING DEGRADATION PROCESS

采用力学性能测试和红外光谱法对自研的光和生物双降解聚乙烯地膜在自然降解过程中的力学性能和化学结构变化进行了研究。结果表明 ,在降解初期使塑膜力学性能迅速下降的主要原因是由光敏剂引发的光降解造成的 ,降解的主要产物为醛、酮、酸、酯和氢过氧化物。经对真菌抗性试验表明 ,当聚乙烯的分子量降至 5 0 0 0左右时 ,易被微生物侵蚀 ,即具有生物降解性。而塑膜中加入的改性淀粉起到加速这种侵蚀的作用。

By means of mechanical property measurement and IR spectrum, the mechanical property and chemical strurcture changes of photo biodegradable PE mulch film are studied during its natural degradation process. The results indicate that photodegradation induced by photosentizer is the main reason for that rapid drop of mechanical properties of the film during its initial period of degradation. The main degradation products are aldehyde, ketone, acide, ester and hydrogenous preroxide. The result of fungus resistant test makes it known that the PE is easily eroded by microbe when its molecular weight decrease to about 5000, that means it is biodegradable. The modified starch existed in the film can accelerate this kind of erosion.