碳纤维形貌结构对其电化学氧化行为及其复合材料界面性能的影响

通过调控原丝工艺,制备得到形貌结构不同、力学性能相近的PAN基碳纤维(CF),用以模拟碳纤维表面光滑与沟槽结构对其电化学氧化行为的影响。研究表明:原始形貌光滑碳纤维在电化学过程中保持形貌能力较强,相同的电化学氧化强度下,其表面氧碳比高于原始表面粗糙的碳纤维,表明其氧化程度高。X射线光电子能谱(XPS)分峰结果表明,二者表面氧含量差别来自于表面羰基含量的差异。力学性能测试结果表明具有沟槽形貌的碳纤维拉伸强度及拉伸模量提高的幅度较大,其中拉伸强度提高最大值为17.3%。将氧化前后的碳纤维制备成碳纤维增强树脂基复合材料,探讨碳纤维形貌结构对其复合材料界面性能的影响。结果表明:由具有沟槽形貌的碳纤维制备得到的复合材料层间剪切强度(ILSS)较高,表明碳纤维表面物理形貌也是影响复合材料界面的重要因素。

Influence of carbon fiber morphology structure on electrochemical oxidation behaviors and interfacial properties of its composites

By regulating spinning process of polyacrylonitrile (PAN) precursor, PAN based carbon fibers (CF) with rough surface and CF with smooth surface were produced, both of which share the same chemical structure as well as similar mechanical property to simulate the influence of surface morphology on the electrochemical oxidation behaviors. Under the same oxidized condition, CF with smooth surface shows a higher morphology resistance, and the O to C ratio is much more than that on CF with rough surface, indicating a higher oxidation degree of the former. XPS spectra reveals that the difference of O to C ratio is probably due to the changes of the relative amount of carbonyl groups on carbon fiber surface. The tensile strength and tensile modulus of CF with rough surface could be improved, however, the tensile strength could be obviously improved to a maximum of 17.3% at the initial stage of electrochemical oxidation. The interlaminar shear strength (ILSS) of carbon fiber reinforced epoxy composite was measured by a fragmentation test, and it is suggested that a better interfacial adhesion could be obtained from rough-surface carbon fiber reinforced epoxy composite, indicating the reinforced mechanism between carbon fiber and epoxy matrix is prone to be anchor force rather than chemical interaction.