气相生长法在炭纤维上生长二次纳米炭纤维

VAPOR GROWN SECONDARY CARBON NANOFIBER OBTAINED ON THE PRECURSOR PAN—BASED CARBON FIBER

以苯为炭源，以铁盐溶液为催化剂，在PAN基炭纤维上气相生长二次纳米炭纤维，可以增加炭纤维增强复合材料的层间剪切力。催化剂浓度和苯的流量不仅对二次纤维的收量有影响，而且还影响着母体炭纤维本身的特性，特别是催化剂溶液的浓度影响着二次纤维生长的均匀性。实验证明，二次纤维均匀分布在母体炭纤维上的最佳条件为：Fe（NO3）3溶液的浓度为0．01wt％，苯的流量为25ml／min。二次纤维的生长是按溶解-液相扩散-析出机制进行的。SEM观察发现．相邻的母体炭纤维被二次纤维连接起来，形成一种网状结构，故可以增加复合材料的层间剪切力，且不改变母体炭纤维的特性。用这种纤维增强的复合材料，有可能使裂纹分叉，提供多种通道延缓裂纹扩展，提高材料的断裂韧性。

The vapor-grown secondary carbon nanofibers grown on PAN - based carbon fibers from benzene, using Fe salt solution as catalyst, hydrogen as carrier gas were prepared. It may increasing to the interlaminar shear strangth of the composites by the reinforcement of carbon fibers. Concentration of Fe salt solution and flow rate of benzene have the effect on the yield of secondary carbon fibers not only and the properties of the precusor carbon fibers but also. In particular. concentration of Fe salt solution has the effect on uniform growtb of VGCNFs on the precusor carbon fibets. Experhoental results indicated that the secondary carbon fibers can be grown uniformly on the surfuce of the precusor PAN -based carbon fibers using appropriate catalrrt concentration of Fe (Nos) a (0.01wt%) and flow rate of benzene (25ml/min ). Though SEM observation. it was founded that the adjacent precusor carbon fibers were linked by the VGCNFs to form an interloking network. which is expected to improve interlaminar sheat strength and no changed the properties of carbon fibers precusor. In order to prohibit delamination of carbon fiber reinforced composite materinls. supply some ways to delay the delamination and increassing its toughness.