纳米SiO_2改性炭纤维乳液上浆剂的性能评价

Evaluation of emulsion type sizing modified by nano-SiO_2 for carbon fiber

采用纳米SiO2改性环氧树脂乳液上浆剂和未改性乳液上浆剂对聚丙烯腈(PAN)基炭纤维进行表面上浆。通过静置沉淀法和光学显微镜评价了两种乳液的稳定性。利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)、原子力显微镜(AFM)和动态接触角测试仪(DCAA)研究了未上浆、未改性和改性上浆炭纤维的表面性能,并用单纤维碎裂法探讨了上浆剂对炭纤维与环氧树脂界面黏结的影响。结果表明:未改性和经纳米SiO2改性的两种乳液粒径较小,稳定性较好,而前者优于后者。上浆后,炭纤维表面的粗糙度和表面能都增大,而且最大值出现在改性乳液上浆炭纤维的表面。改性乳液上浆单纤维复合材料拥有最大的界面剪切强度(IFSS),比未改性上浆的高出27.2%;改性上浆炭纤维与基体的调和平均黏结功(W(ah))和几何平均黏结功(W(ag))也分别高出未改性上浆的12.7%和11.7%。

Polyacrylonitrile （PAN）-based carbon fibers （CF） with nano-SiO2 modified emulsion sizing and unmodified emulsion sizing were prepared. The stability of both emulsions was studied by the static precipitation method and optical microscopy. Scanning electron microscope （SEM）, X-ray energy spectrum tester （EDS）, atomic force microscopy （AFM） and dynamic contact angle analysis （DCAA） were used to study the surface property changes of the CF without sizing and the CF with unmodified sizing and modified sizing. The interracial adhesion properties between CF and the matrix resin were evaluated by the single fiber fragmentation test. The results show that the size of both unmodified and modified emulsion particles is little and both emulsion stabilities are better; moreover, the former is more excellent than the latter. The surface energy and toughness of CF are improved after sizing. Furthermore, the surface energy and toughness of the CF with modified sizing have maximum values. The interracial shear strength （IFSS） value of the CF with modified sizing is 27.2% higher than that of the CF with unmodified sizing. The harmonic mean work of adhesion （Wa（h）） and geometrical mean work of adhesion （Wa（g）） between sizing modified carbon fibers and the matrix resin are also increased by 12. 7 % and 11.7 %, respectively, compared to those of the CF with unmodified sizing.