低密度聚乙烯热氧老化行为及老化动力学  

Thermo-Oxidative Degradation Behavior and Aging Kinetics of Low Density Polyethylene

作　　者：代军[1] 晏华[1] 郭骏骏 杨健健[1] 张寒松[1] 

机构地区：[1]中国人民解放军后勤工程学院化学与材料工程系,重庆401331 [2]部队,江苏无锡214000,273801

出　　处：《塑料》2017年第1期121-124,128,共5页Plastics

基　　金：军队后勤科研项目(BX211J001)

摘　　要：分别在80、95、110℃热氧老化环境中对低密度聚乙烯(LDPE)进行了64 d的人工加速老化试验,以研究其在光氧环境下的老化行为及规律。利用衰减全反射红外光谱技术(ATR-FTIR)、差示扫描量热法(DSC)、扫描电子显微镜(SEM)、力学试验和老化动力学方法分别研究了LDPE的化学结构、熔融特性、表面微观形貌、弯曲强度和老化动力学参数的变化规律,探究了LDPE的老化行为及老化机理。结果表明:LDPE分子结构中产生羰基、羟基等含氧基团,分子链断裂,支链增加,至老化64 d后,羰基指数和羟基指数分别上升至8.8和12.6,熔融特性下降,LDPE表面破坏严重,老化作用剧烈,在110℃条件老化64 d后,LDPE弯曲强度下降了43.7%。建立了以弯曲强度为参数的LDPE热氧老化反应动力学方程,其热氧老化反应的活化能为33.9 kJ/mol。The artificial accelerated aging test of low density polyethylene （LDPE）was carried out for different time periods up to 64 days under thermo-oxidative environment at the temperature of 80,95,110 ℃. The influence on chemical structure, melting characteristic, surface morphology, bending strength and aging kinetics parameters evolution of LDPE after thermo-oxidative aging were studied by attenuated total reflection infrared spectroscopy （ ATR-FTIR）, differential scanning calorimetry （DSC）, scanning electron microscope （SEM）, mechanics experiments and aging kinetics method. The degradation behavior and aging mechanism of LDPE were explored. The results showed that during the aging period, the concentration of carbonyl and hydroxyl groups increases,the rupture of molecular chain intensifies. After 64 days of aging, the carbonyl index and hydroxyl index increase to 8.8 and 12.6, respectively. The melting characteristic decline and the aging degree of surface microstructure was severe. The bending strength of LDPE decline by 43.7% after 64 days of aging at 110 ℃. The first-order kinetics equation of LDPE thermal-oxidative aging was established with bending strength as parameter, its activation energy was 33.9 kJ/mol.

关 键 词：低密度聚乙烯 热氧老化 动力学 活化能 SEM 弯曲强度 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]