微波固化碳纤维/环氧树脂复合材料NOL环及其力学性能

Mechanical Properties of NOL Rings of Carbon Fiber / Epoxy Composites Cured by Microwaves

采用微波固化技术,对碳纤维/环氧树脂复合材料NOL环进行了固化试验研究。综合运用红外光谱、微观CT扫描系统、力学拉伸试验机和扫描电子显微镜等试验方法分析材料的固化行为、微观形态及力学性能,并与传统热固化试样进行了对比。研究结果表明,微波固化方式与传统热固化方式的固化机理不同,微波固化可显著缩短固化周期;微波固化过程中未引入新的化学反应,且2种固化方式所获得的固化产物化学结构相同;CT扫描分析揭示出微波功率的大小对碳纤维复合材料孔隙率有着重要的影响;在相同固化温度条件下,微波固化复合材料NOL环的拉伸强度和层间剪切强度均低于热固化复合材料,这主要归因于微波固化复合材料具有较大的孔隙率;扫描电镜分析表明微波固化复合材料树脂和纤维的粘接情况要稍好于热固化复合材料。

Comparative studies were carried out on the NOL rings of carbon fiber/epoxy composites cured by microwave （MW） curing technique and thermal curing technique. The curing behavior, microstructure as well as mechanical properties of cured composites were well investigated through a series of methods and equipments including FT-IR, micro-CT system, mechanical tension test machine and SEM. The re_sults show that the curing mechanism for MW curing technique is different from conventional thermal curing technique and the cure cycle is greatly shortened. FT-IR measurements reveal that MWs do not initiate any new chemical reactions during the curing process and both MW and thermally cured composites have the same chemical structure. CT scan analysis indicates that the MW power u~~~l in the curing process has significant effect on the void content of cured composites. Moreover, the MW cured composites exhibit lower tensile and interlaminar shear strength as compared to thermally cured counterparts when using .same curing temperature, which is mainly ascribed to the higher void content contained in the MW cured composites. Furthermore, the adhension between the fiber and resin is slightly better for MW cured composites compared with thermally cured ones, which is confirmed by SEM micrographs.