摘要
通过对力学性能、红外光谱、粘均分子量及扫描电镜的分析,研究了煤/聚乙烯塑料在室内加速老化实验中的降解性能,并运用降解机理对实验过程进行解析及验证。结果表明,煤降解剂引发的交联和降解反应控制了薄膜的强度,使其柔韧性一直降低,且在整个120h光照过程中,断裂伸长率一直呈下降趋势;72h前是聚合物的氧化诱导期及衰变期,之后进入完全降解期。煤在改性塑料光照过程中引发自由基反应,引入羰基,导致聚乙烯大分子断链降解;共聚物的粘均分子量整体呈降低趋势,说明光照促进聚合物的降解,降解和交联交替控制着反应。煤/聚乙烯的光降解过程遵循链引发、链增长、链终止反应机理,在煤大分子光催化作用下,改变了聚乙烯常规光降解过程,加速了聚乙烯大分子断链和分子量降低。运用煤/聚乙烯塑料降解机理,能够解释样品力学性能变化、化学结构中羰基指数变化、分子量降低及降解过程中的现象和规律。
By tests of mechanical property,IR spectroscopy,viscosity average molecular weight and scanning electron microscopy,the degradation of titled plastics was studied in accelerated-aging experiments under indoor conditions,and the degradation mechanism was used to analyze and confirm the experimental data.The results showed that the strength of the film was controlled by crosslinking and degradation reactions induced by coal degradation,but its flexibility has been reduced,and the percentage of breaking-elongation of the film shows a downward trend during the entire process of illumination for 120h.At illuminating for 72h the main procedure was the oxidation induction and decay of polymer,and then was its complete degradation.Free radical reactions were caused by coal in the process of lighting modified plastics,and the introduction of the carbonyl group resulted in the scission and degradation of Polyethylene（PE） macromolecular chain.The decrease of the viscosity average molecular weight of copolymer indicated that lighting promoted the degradation of polymer,and crosslinking and degradation alternately controlled the reaction.The photo-degradation process of coal/PE followed the reaction mechanism of chain initiation,chain growth,and chain termination.By the photo-catalysis of coal macromolecules,the conventional photo-degradation process of PE has been changed,so the chain scission of PE macromolecular has been accelerated and the molecular weight reduced.The degradation mechanism of Coal/PE plastic could be used to explain the rules of the changed carbonyl index in samples,the reduction of molecular weight and degradation process.
出处
《化学通报》
CAS
CSCD
北大核心
2012年第10期903-907,共5页
Chemistry
基金
国家自然科学基金青年基金项目(21107021)
河南省科技创新人才基金项目(124200510023
124100510025)
郑州市普通科技攻关项目(121PPTGG476)资助
关键词
煤
聚乙烯
塑料
光降解
机理
Coal
Polyethylene
Plastics
Photo degradation
Mechanism
