紫外老化和热老化对农用薄膜性能影响的对比分析

Comparison and Analysis of Performance of Agricultural Plastic Film in Ultraviolet Aging and Thermal Aging

[目的]研究老化行为是解决农用薄膜的老化现象、防止老化的基本手段。[方法]采用加速紫外老化和热老化2种方法,对老化前后聚氯乙烯(PVC)薄膜和高密度聚乙烯(HDPE)薄膜的拉伸性能、透气性能和透湿性能等进行对比分析。[结果]在2种老化方式下,HDPE薄膜的拉伸强度都下降,在老化120 h时,热老化拉伸强度降低6.07%,而紫外老化拉伸强度下降15.08%;PVC薄膜在老化120 h时,热老化拉伸强度上升33%,而紫外老化拉伸强度下降13.8%。在2种老化方式下,HDPE薄膜透气量都上升,老化120 h时,热老化透气量增加107.64%,而紫外老化透气量增加219.39%;PVC薄膜在达到最大透气量后缓慢降低。2种老化方式下,在老化120 h内,HDPE薄膜透湿量都是先降低后上升,而PVC薄膜透湿量都下降。[结论]该研究可以为合理使用农用塑料膜,降低老化的影响提供参考依据。

[Objective] Researching on the degradation behavior of mulch plastic film is a basic method for solving degradation phenomena and preventing degradation.[Method] Using artificial accelerated ultraviolet aging and thermal aging,the properties of tensile strength,air permeability and moisture permeability before and after aging were compared and analyzed,taking PVC film and HDPE film as objects.[Result]The tensile strength of HDPE in thermal aging decreased by 6.07％ and the value was 15.08％ in ultraviolet aging for 120 hours.The tensile strength of PVC in ultraviolet aging fell 13.8％,on the contrary,it raised 33％ in thermal aging at 50 ℃ for 120 hours.The air-permeability of HDPE in thermal aging increased by 107.64％,while it increased by 219.39％ in ultraviolet aging,the air-permeability of PVC reached to the maximum then declined slowly in two kinds of aging methods.Similarly in these two kinds of aging methods,the moisture-permeability of HDPE all decreased and then increased,nevertheless the moisture-permeability of PVC declined entirely.[Conclusion] The research could provide reference basis for the rational utilization of agricultural mulch plastic film and the reduction of the aging effects.