中文摘要：

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30-473K及30-493K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160，120K；玻璃化转变点温度L分别为270，260K和橡胶态到粘流态的转变点温度Tf=380K（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TγL分别比环氧树脂低0，10K和40K．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L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．

英文摘要：

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 （Zm） in both epoxy and epoxy/rectorite nanocomposite.