增韧剂对尼龙6/碳纤维复合材料性能的影响

Influence of Flexibilizers on the Properties of Polyamide 6/Carbon Fiber Composites

分别以马来酸酐接枝三元乙丙橡胶(EPDM-g-MAH)、马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)、马来酸酐接枝氢化苯乙烯-丁二烯嵌段共聚物(SEBS-g-MAH)为增韧剂,采用双螺杆挤出机制备了3种增韧改性尼龙6/碳纤维(PA6/CF)复合材料。采用力学性能、扫描电子显微镜(SEM)、差示扫描量热分析(DSC)、X射线多晶衍射分析(XRD)等手段对复合材料的界面结构和性能进行研究。结果表明:增韧后,PA6/CF复合材料的力学性能提高,其中,EPDM-g-MAH增韧改性的PA6/CF复合材料(PA6/CF/EPDM)的拉伸强度和冲击强度相对于PA6/CF分别提高了7%和16%,碳纤维与基体间的界面结合力显著增强;同时,增韧改性后的PA6/CF复合材料中的尼龙6的结晶度增加且更易形成稳定的α晶型。另外,与PA6/CF相比,增韧剂的加入略微降低了树脂基体的熔点。

Three kinds of flexibilizers,maleic anhydride-grafted ethylene-propylene-diene terpolymer(EPDM-g-MAH),maleic anhydride-grafted polyethylene-octene elastomer(POE-g-MAH)and maleic anhydride-grafted hydrogenated styrene-butadiene-styrene(SEBS-g-MAH),were used to toughen the polyamide 6/carbon fiber(PA6/CF)composites by melt-extrusion.The mechanical properties,morphology,crystalline structure,nonisothermal crystallization and subsequent melting behavior of PA6/CF composites were investigated.Incorporation of flexibilizers improves the mechanical properties of PA6/CF composites.Compared with PA6/CF composites,the tensile strength and impact strength of PA6/CF/EPDM increase by 7%and 16%,respectively.The scanning electron microscopy(SEM)indicates that modification with flexibilizers not only improves the toughness of the matrix resin but also enhances the interfacial adhesion between the carbon fiber and PA6 matrix.Nonisothermal crystallization behaviors and subsequent melting behaviors charactered by differential scanning calorimetry(DSC)show that the onset crystallization temperature(T on),crystallization peak temperature(T p),crystallization enthalpy(ΔH c)and crystallinity(χc)of PA6 in PA6/CF composites increase after incorporation of flexibilizers and multiple melting behaviors owing to the existence of various crystalline forms in PA6.Simultaneously,a slight decrease in temperature of melting peak(T m1)of PA6/CF composites toughened by flexibilizers is observed compared with PA6/CF.X-ray diffraction analysis(XRD)results show that theα-form crystalline structure is favorable in the composites when the PA6/CF composites is toughened by the flexibilizers,which demonstrates the multiple melting behaviors of PA6/CF composites.