热老化对XLPE/OMMT纳米复合材料微观结构和力学性能的影响  

Effect of Thermal Ageing on Microstructure and Mechanical Properties of XLPE/OMMT Nanocomposites

作　　者：许庆重 李秀峰[1] 孙光华 邓繁盛 常锦涛 高嫄 XU Qingzhong;LI Xiufeng;SUN Guanghua;DENG Fansheng;CHANG Jintao;GAO Yuan(College of Electric and Electronic Engineering,Shandong University of Technology,Zibo 255000,China)

机构地区：[1]山东理工大学电气与电子工程学院,山东淄博255000

出　　处：《绝缘材料》2022年第10期25-32,共8页Insulating Materials

基　　金：山东省自然科学基金面上项目(ZR2019MEE100);淄博市张店区校城融合发展计划项目(2021JSCG0009)。

摘　　要：采用熔融共混的方法制备了交联聚乙烯/有机化蒙脱土(XLPE/OMMT)纳米复合材料,通过小角X射线衍射(XRD)、差示扫描量热法(DSC)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)和力学性能测试对试样热老化前后的性能进行表征。结果表明:老化前质量分数为0.5%的OMMT可在基体中达到最佳分散状态,填料掺杂量增多时会团聚;OMMT与XLPE基体仅有较少的化学键联系,两者主要以物理缠结的形式共存;OMMT片层的空间位阻效应使纳米复合材料的结晶度下降。老化后仅有XLPE/OMMT-0.5%试样的层间距减小,结晶度升高;随OMMT掺杂量的增加,层间距会因XLPE分子链断裂和OMMT在基体中的热重排而增大,晶体结构完善性变差,晶体尺寸分布变宽,结晶度显著降低;受热氧反应和热裂解反应的影响,分子链结构破坏严重。老化后XLPE/OMMT-0.5%的力学性能仅小幅度降低,当OMMT质量分数超过0.5%时,材料力学性能劣化严重,变脆变硬。Crosslinked polyethylene/organic montmorillonite(XLPE/OMMT)nanocomposites were prepared by melting blending method.The performance of samples before and after thermal ageing were characterized by small angle X-ray diffraction(XRD),differential scanning calorimetry(DSC),scanning electron microscopy(SEM),Fourier transform infrared spectra(FTIR),and mechanical properties test.The results show that with the mass fraction of 0.5%,OMMT can be well dispersed in the matrix before ageing.However,OMMT agglomerates when the filler doping amount increases.There are only a few chemical bonds between OMMT and XLPE matrix,they mainly coexist in the form of physical entanglement.The crystallinity of nanocomposites decreases due to the space steric effect of OMMT lamella.After ageing,the layer spacing of XLPE/OMMT-0.5%samples decreases and the crystallinity increases.With the increase of OMMT doping amount,the interlayer spacing of OMMT increases due to the breakdown of XLPE molecular chain and the thermal rearrangement of OMMT in matrix.Due to thermal ageing,the completeness of crystal structure of nanocomposites gets worse,the crystal size distribution becomes wider,and the crystallinity decreases significantly.The molecular chain structure of nanocomposites is seriously damaged by thermal oxidation and thermal cracking.The mechanical property of XLPE/OMMT-0.5%decreases slightly after ageing,and when the content of OMMT exceeds 0.5%,the mechanical properties of nanocomposites decrease seriously.And the samples become brittle and hard.

关 键 词：热老化 有机化蒙脱土 纳米复合材料 微观结构 力学性能 

分 类 号：TM215[一般工业技术—材料科学与工程]