PE-LLD散光膜氙灯加速老化行为及机制  

Xenon lamp accelerated aging behavior and mechanism of PE-LLD light-diffusing film

作　　者：张怡[1] 王富龙 钟颜阳 钟安澜 龙思宇 杨康 ZHANG Yi;WANG Fuong;ZHONG Yanyang;ZHONG Anan;LONG Siyu;YANG Kang(Guizhou Institute of Metallurgy and Chemical Engineering,Guiyang 550014,China;Guizhou Nanomaterials Engineering Center,Guiyang 550014,China)

机构地区：[1]贵州省冶金化工研究所,贵阳550014 [2]贵州省纳米材料工程中心,贵阳550014

出　　处：《工程塑料应用》2024年第3期119-125,共7页Engineering Plastics Application

基　　金：贵州省基础研究计划[2019]1448号;贵州省基础研究计划[2020]1Z043号;贵阳市科技计划[2021]43-21号;贵阳市科技计划[2023]6-4号

摘　　要：农用聚乙烯散光棚膜可在较高透光率条件下提高雾度,将透过膜面的直射光转为散射光,促进膜内植株全维度获取有效光辐射。通过引入散光剂制备线型低密度聚乙烯(PE-LLD)散光膜,实现透光率90.99%、雾度62.29%,较空白对照膜透光率降低0.55%、雾度提高152.60%。耐老化性能是PE-LLD棚膜其他功效性能的基础保证,采用氙灯老化对PE-LLD散光膜进行加速降解,其宏观光学与力学性能变化趋势同空白膜一致,二者断裂伸长率分别在13d时降至初始值40.58%与47.01%(完全老化)。综合考察PE-LLD散光膜加速老化过程化学组成、结晶行为、晶粒尺寸及微观形貌变化规律,其老化过程随降解速度变化分3个阶段:老化前期分子链交联密度上升,二次结晶片段堆砌增大结晶度,降解缓慢;老化中期交联与降解并存,界面处散光剂脱落促使膜面破裂,片晶分布连续性降低,降解速度适中;老化后期分子主链降解加剧,膜面裂纹向纵深延展,力学性能快速降解至完全老化。研究表明,引入散光剂可在不影响PE-LLD棚膜宏观使用功能与老化降解性能的基础上有效提高雾度,实现散射光调控。Agricultural polyethylene light-diffusing shed film can improve haze under the condition of high luminousness,and transform the direct light into diffused light,which can promote the inside plant to obtain effective light radiation in all dimensions.Linear low density polyethylene(PE-LLD)light-diffusing film was prepared by adding light diffusion agent,achieving a luminousness of 90.99% and a haze of 62.29%,which were 0.55% lower and 152.60% higher than the blank control film.Aging resistance is the basic guarantee of other functional properties of PE-LLD shed film,xenon lamp aging was used to accelerate the degradation of PE-LLD light-diffusing film,the macroscopic optical and mechanical property variation trend is consistent with blank film,and elongation at break of two films respectively decrease to 40.58%and 47.01%of the initial value at 13 d(completely aged).The chemical composition,crystallization behavior,crystallite dimension and morphology of the light-diffusing film during accelerated aging were investigated,aging process varied with degradation rate in three stages.In early stage of aging,the crosslink density of molecular chains rise,crystallinity improve with the secondary crystallization accumulation,the degradation rate is slow.In middle stage of aging,crosslinking and degradation reaction co-existed,light diffusing agent falls off from the interface and causes the film surface to break,the continuity of crystallization chains distribution decrease,the degradation rate is moderate.In later stage of aging,the degradation of the molecular main chain intensifies,film breakages extend to the depth,mechanical properties rapidly degrade to complete aging.The study shows that light diffusion agent can effectively improve haze and realize diffused light control without affecting the macro function and aging degradation performance of PE-LLD shed film.

关 键 词：线型低密度聚乙烯 散光膜 氙灯老化 性能变化 行为及机制 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]