淀粉/聚乙烯薄膜中聚乙烯的降解特性研究

对含３０％淀粉的淀粉／聚乙烯薄膜进行环境降解、环境生物降解和环境曝晒试验，发现淀粉／聚乙烯薄膜在环境中暴晒降解的速度远远大于生物降解的速度，在应用环境中经过４周的降解，薄膜中聚乙烯的分子量损失达６２．５％；经５周的曝晒降解后，薄膜中聚乙炮的分子量损失达８７．５％；薄膜降解后，平板流变粘度降低２个数量级以上。

Degradation Behavior of Polyethylene in the Starch-Polyethylene Film

The degradation behavior of polyethylene in the starch polyethylene films was studied.The samples containing 30% starch were evaluated for their degradability by exposing them to the normal applied environment,biologic environment and sunlight.The polyethylene in the experimental samples was degraded much more rapid under sunlight than that in the biologic environment.The polyethylene molecule weight in the sample of which degraded in the normal applied environment after 4 weeks reduced 62 5% compared with the original sample.Exposed under the sunlight after 5 weeks,its polyethylene molecular weight reduced 87 5% compared with the original sample and its viscosity reduced to the centi grades compared with the original samples.Although the sample weight reduced up to 28% in biologic environment after 4 weeks,however,its polyethylene molecule weight reduced less than 10% compared with the original sample and its viscosity had little change.It is obvious that starch can accelerate the photochemistry degradation of the polyethylene.The SEM showed that the surface of the sample was flatting after a week in the biologic environment.Some visualize holes were found after 2 weeks and the holes sized 5 mm to 10 mm were found after 3 weeks degraded in the biologic environment but that they are caused by microorganism or not is not confirmed until now.