回收高密度聚乙烯的热降解动力学研究  

Kinetics of Thermal Degradation of Recycled High- Density Polyethylene

作　　者：辛闻[1] 张富青[1] 袁军[1] 唐兴兴[1] 张磊[1] 

机构地区：[1]武汉工程大学,湖北武汉430073

出　　处：《山东化工》2016年第7期37-41,共5页Shandong Chemical Industry

摘　　要：研究了回收高密度聚乙烯的热降解动力学参数。采用热重分析法,分别测定了在氮气气氛中5、10、15、20℃/min四种不同升温速率下的热降解过程,得到四条热重曲线,采用kissinger法及Flynn-Wall-Ozawa法对改性前后PE回料的热分解动力学进行了分析,并用Crane公式对反应级数进行了求解。结果表明无论是否改性,PE回料的热失重均为一步降解反应,且提高升温速率后热重曲线向高温方向移动,但未改性PE回料体现出的热滞后现象要更加严重。kissinger法求得改性前材料的降解活化能E1=75.09k J/mol,表观指前因子ln A1=20.23;改性后降解活化能E2=316.18k J/mol,表观指前因子ln A2=43.22。ozawa法求得改性后PE回料的不同转化率下降解活化能E均有所提高,且活化能与转化率的关系曲线更加复杂。Crane公式求得改性前的PE回料热降解反应反应级数为0.933369,线性拟合系数为0.98909;改性后,其反应级数为0.961909,线性拟合系数为0.99565。且可由断裂的分子理论得出改性后PE回料的力学性能得到了增强。Thermo gravimetric analysis under nitrogen was used to investigate the thermal decomposition process of high-density polyethylene（ HDPE） research. The thermal degradation kinetic parameters of virgin and modified recycled HDPE（ r- HDPE） were studied. The Kissinger,and Flynn- Wall- Ozawa methods was used to determine the apparent activation energy（ Ea） of the thermal degradation of the virgin and modified r- HDPE. Crane equation was used to study the reaction order of thermal degradation. The results showed that,from TG and DTG profiles,both virgin and modified resin was one-step- degradation reaction,while the thermal hysteresis of the modified PE was more serious with the increase of heating speed. From calculated kinetic parameters,thermal stability of virgin r- HDPE was lower than those of modified r- HDPE.Interestingly,the result gotten by Flynn- Wall- Ozawa methods showed the degradation process of modified r- HDPE is more complex. From calculated reaction orders,both subject degraded in random nucleation and growth mechanism.

关 键 词：TGA 热降解 回收HDPE 动力学 热分析 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]