环氧树脂/累托土纳米复合材料结构转变特性的正电子谱学研究

环氧树脂/累托土纳米复合材料结构转变特性的正电子谱学研究 Characteristic of Structure Transition in Epoxy/Rectorite Nanocomposites by Positron Annihilation 张明 ZHANG Ming1 1 first-author 祁会霞 QI Huixia2 2 刘黎明 LIU Liming3 3 方鹏飞 FANG Pengfei3 3 中原工学院理学院 中原工学院理学院 Department of Science,Zhongyuan University of Technology Department of Science,Zhongyuan University of Technology 中原工学院计算机学院 中原工学院计算机学院 School of Computer Science,Zhongyuan University of Technology School of Computer Science,Zhongyuan University of Technology 武汉大学物理科学与技术学院 武汉大学物理科学与技术学院 School of Physics and Technology,Wuhan University School of Physics and Technology,Wuhan University 采用正电子湮没寿命谱（PALS）技术,通过探测聚酰胺固化环氧树脂（epoxy）及环氧树脂/累托土（epoxy/rectorite）纳米复合材料分别在30 4 73 K及30 4 93 K温度区间内自由体积特性的变化,得到了epoxy和epoxy/rectorite两种材料中3个结构转变点温度为:次级转变点温度Tγ分别为160,120 K;玻璃化转变点温度Tg分别为270,260 K和橡胶态到粘流态的转变点温度Tf=380 K（两种材料相同）.比较两种材料的结构转变点,发现纳米复合材料Tf,Tg和Tγ分别比环氧树脂低0,10 K和40 K.说明累托土的加入影响了复合材料低温下的自由体积特性.在温度高于熔融温度Tm时,发现两种样品中自由体积浓度有较快的下降,归因为材料中分子链段运动非常剧烈,较小的孔洞消失. The structural transformation of epoxy（cured by polyamide） and epoxy/rectorite nanocomposite（with 0.5% rectorite content） are studied by positron annihilation lifetime spectrum（PALS） as a function of temperature from 30 to 473 K and from 30 to 493 K,respectively.For epoxy and epoxy/rectorite nanocomposite,the glass transition temperatures（Tg） are observed to be 270 K and 260 K,the second transition temperatures（Tγ） are 160 K and 120 K,the viscous flow temperatures（Tf） are 380 K and 380 K,respectively.The Tf,Tg and Tγ of the nanocomposite are 0,10 K and 40 K lower than those of epoxy,respectively. The result shows that properties of the free-volume in nanocomposite have been changed by the rectorite platelets fully separated in the material at low temperature.At the same time,we find that the intensity of o-Ps decreases with increase of the temperature above the melting temperature（Tm） in both epoxy and epoxy/rectorite nanocomposite. 环氧树脂 纳米复合材料 正电子湮没 结构转变 自由体积 epoxy nanocmposite positron annihilation structure transition free-volume TB383.1 国家自然科学基金（50577068）资助项目 2008-03-01 2021-04-01 3