改性碳纤维增强尼龙6复合材料的制备及性能

通过硝酸酸化处理及尼龙溶液浸渍上浆处理对碳纤维(CF)进行表面改性,制备高强度、高模量,同时具有低熔指和优异加工性能的CF增强尼龙6(PA6)复合材料。采用扫描电镜(SEM)、差示扫描量热仪(DSC)和熔融指数仪等方法,对复合材料的微观结构、力学性能和结晶行为进行测试和表征。结果表明,经过PA6溶液浸渍上浆处理后的CF表面形成了一层PA6薄膜覆盖层,大大增强了CF与PA6基体的结合力,改善了CF的分散性,提升了复合材料整体的强度与模量,改性CF加入量为8%(质量分数)时复合材料拉伸强度提升80.8%,弹性模量提升513.9%。进一步对复合材料结晶行为的分析表明,改性CF的加入能够促进PA6由γ晶型向更稳定的α晶型转变,提高其结晶温度及结晶速率,使复合材料的结晶更加均匀、完善,从而提高体系黏度,降低复合材料熔融指数,显著提升了复合材料的加工性能。

Preparation and properties of modified carbon fiber reinforced polyamide 6 composites

The carbon fibers(CF)were surface modified by nitric acid treatment and polyamide 6(PA6)solution sizing treatment,and a series of CF/PA6 composites with high strength and high modulus,low melting index,and excellent processability were prepared.Scanning electron microscope(SEM),differential scanning calorimeter(DSC)and melt index meter were used to test and characterize the microstructure,mechanical properties and crystallization behavior of the composite materials.The results show that a layer of PA6 film is formed on the surface CF after immersion and sizing treatment with PA6 solution,which greatly enhances the binding force between the fiber and PA6 matrix,and improves the dispersibility of CF.The overall strength and modulus of the composites are improved.The tensile strength of the CF/PA6 is increased by 80.8% and the elastic modulus is increased by 513.9% when the modified CF amount is 8%(mass fraction).The addition of modified CF can promote the transition of PA6 from the γ crystal form to a more stable α crystal form.At the same time,the crystallization temperature and crystallization rate of the composites are increased,so that the crystallization of the composites are more uniform,thereby reducing the melting index of the composite and improving its processing performance.