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首页> 外文期刊>Journal of Applied Polymer Science >Kinetic study of hindered amine light stabilizer photografting in low density polyethylene films under natural weathering conditions
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Kinetic study of hindered amine light stabilizer photografting in low density polyethylene films under natural weathering conditions

机译：自然风化条件下低密度聚乙烯薄膜中受阻胺光稳定剂光接枝的动力学研究

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摘要

The photografting kinetic of a hindered amine light stabilizer (HALS) was studied in low density polyethylene (LDPE) films under natural weathering conditions. The HALS (PBH-3) was added to the polymer at a concentration of 0.3% (w/w). The photografting kinetic of polymer bound HALS (PBH-3) was determined by direct spectroscopic measurements through the absorption band area of the stabilizer centered at 308 nm in the UV spectra and 1605 cm(-1) in Fourier transform IR (FTIR) spectra, which correspond to benzylidene malonate ester and benzylidene malonic groups, respectively. In parallel, measurements were carried out on the free PBH-3 content after chloroform extraction of the photostabilizer from the polymer matrix by means of UV and gas chromatography methods. The results showed that in natural weathering the grafting of PBH-3 occurred in the LDPE film after very short exposure times of 127 and 168 h as determined by UV and FTIR, respectively. Moreover, the curves describing both the photografting and the free HALS kinetics exhibited similar profiles. The mechanism of photografting implies a rapid photoreaction between the methylenic double bond of the stabilizer and the macroalkyl radicals of the polymer, resulting in formation of polymer-bonded aminyl derivatives of the stabilizer. (C) 2002 Wiley Periodicals, Inc. [References: 24]
机译：在自然风化条件下，在低密度聚乙烯（LDPE）薄膜中研究了受阻胺光稳定剂（HALS）的光接枝动力学。将HALS（PBH-3）以0.3％（w / w）的浓度添加到聚合物中。聚合物结合的HALS（PBH-3）的光接枝动力学是通过直接光谱测量通过稳定剂在UV光谱中的308 nm和傅立叶变换IR（FTIR）光谱中的吸收带区域确定的，吸收带的面积为308 nm，它们分别对应于亚苄基丙二酸酯和亚苄基丙二酸酯基。平行地，通过UV和气相色谱法，从聚合物基质中氯仿提取光稳定剂后，对游离PBH-3含量进行测量。结果表明，在自然风化下，分别通过紫外线和FTIR分别测定了127和168小时的非常短的曝光时间后，LDPE膜中发生了PBH-3的接枝。而且，描述光接枝和自由HALS动力学的曲线显示出相似的曲线。光接枝的机理意味着稳定剂的亚甲基双键与聚合物的大烷基自由基之间的快速光反应，导致形成稳定剂的聚合物键合的氨基衍生物。 （C）2002 Wiley Periodicals，Inc. [参考：24]

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