Photocrosslinking and related properties of intumescent flame-retardant LLDPE/EVA/IFR blends
Photocrosslinking and related properties of intumescent flame-retardant LLDPE/EVA/IFR blends
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DOI：
10.1002/pat.1980
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发表时间：
2012-05-01
影响因子：
3.4
通讯作者：
Qu, Baojun
中科院分区：
文献类型：
--
作者：
Ye, Lei;Wu, Qianghua;Qu, Baojun
采用凝胶测定、热延伸试验、锥形量热法（CCT）、热重分析法（TGA）、热重分析法（TGA）、光引发剂和交联剂对无卤阻燃线性低密度聚乙烯/聚乙烯（乙烯-醋酸乙烯）共混物（LLDPE/EVA）与磷氮化合物（NP）膨胀阻燃剂（IFR）进行了光引发交联，并对其相关性能进行了表征。傅里叶转移红外（FTIR）光谱，扫描电子显微镜（SEM），机械性能测量，极限氧指数（LOI）， UL-94和耐水性测试。凝胶含量和热延伸率（HER）的数据表明，填充NP的LLDPE/EVA/IFR共混物很容易交联到凝胶含量在75%以上的情况下，紫外线照射5？在适量的光引发剂和交联剂的作用下。CCT和LOI数据表明，光交联可以显著降低LLDPE/EVA/NP共混物的热释放率（HRR），降低1015%，延长燃烧时间，并提高两个LOI值。热重分析和动态红外光谱结果表明，光交联LLDPE/EVA/NP样品的热降解速率比未交联LLDPE/EVA/NP样品慢，热氧化降解温度更高。通过扫描电镜观察到的炭化残留物的形态结构表明，光交联LLDPE/EVA/NP样品形成的致密炭化层对增强阻燃性能和热性能有重要作用。力学性能和耐水性测试数据表明，光交联可以显著提高LLDPE/EVA/NP样品的力学性能和耐水性。版权所有：John Wiley & Sons， Ltd。
The photoinitiated crosslinking of halogen-free flame retarded linear low density polyethylene/poly(ethylene-co-vinyl acetate) blends (LLDPE/EVA) with the intumescent flame retardant (IFR) of phosphorous-nitrogen compound (NP) in the presence of photoinitiator and crosslinker and their characterization of related properties have been investigated by gel determination, heat extension test, cone calorimeter test (CCT), thermogravimetric analysis (TGA), Fourier transfer infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), mechanical properties measurements, limiting oxygen index (LOI), UL-94, and water resistance test. The data from the gel content and heat extension rate (HER) show that the LLDPE/EVA/IFR blends filled with NP are readily crosslinked to a gel content of above 75% and the HER values reach about 50% by UV-irradiation of 5?sec under suitable amount of photoinitiator and crosslinker. The data obtained from the CCT and LOI indicate that photocrosslinking can considerably decrease the heat release rates (HRR) by 1015%, prolongate the combustion time, and increase two LOI values for the LLDPE/EVA/NP blends UV irradiated for 5 sec. The results from TGA and the dynamic FTIR spectra give the evidence that the photocrosslinked LLDPE/EVA/NP samples show slower thermal degradation rate and higher thermo-oxidative degradation temperature than the uncrosslinked LLDPE/EVA/NP samples. The morphological structures of charred residues observed by SEM give the positive evidence that the compact charred layers formed from the photocrosslinked LLDPE/EVA/NP samples play an important role in the enhancement of flame retardant and thermal properties. The data from the mechanical tests and water-resistant measurements show that photocrosslinking can considerably improve the mechanical and water-resistant properties of LLDPE/EVA/NP samples. Copyright (C) 2011 John Wiley & Sons, Ltd.