UV老化对ZnO填充PA6/LGF复合材料性能的影响

用熔融共混法制备出长玻璃纤维(LGF)含量为30%的LGF增强尼龙6(PA6)/ZnO(PA6/LGF/ZnO)复合材料,并采用氙灯紫外(UV)老化法研究了ZnO含量为0%~8%及UV老化时间为0~800 h对复合材料力学性能和结晶性能的影响。结果表明,经UV辐照后,PA6/LGF/ZnO复合材料的拉伸强度升高,韧性下降,其中当ZnO添加量为6%时,复合材料在800 h老化后的拉伸强度和缺口冲击强度保留率较未添加ZnO的复合材料分别提高了5.39%和4.98%。SEM分析表明在UV老化过程中,LGF与PA6基体之间的界面并未受到明显破坏,老化主要集中发生在PA6基体上。随着老化时间的延长,PA6/LGF复合材料中的PA6出现UV交联而使其结晶度从26.19%降低至20.70%;对于ZnO含量为6%的PA6/LGF/ZnO复合材料,老化800 h后其结晶度仅从22.92%下降至21.34%,PA6/LGF/ZnO复合材料整体上的结晶性能趋于稳定。

Effects of UV Aging on Properties of PA6/LGF Composites Filled with Zinc Oxide

The long glass fiber (LGF) reinforced polyamide 6 (PA6) composites filled with ZnO (PA6/LGF/ZnO) with 30% LGF were prepared by melt blending method. The mechanical and crystallization properties of PA6/LGF/ZnO composites with different contents of ZnO and different aging time were analyzed by the method of xenon lamp ultraviolet (UV) irradiation aging. The results in mechanical properties show that all the PA6/LGF/ZnO composites after UV aging have an increase in tensile strength and a decrease in impact strength which means a decrease in toughness. When the contents of ZnO are 6%,the retention rate of ten-sile strength and notched impact strength after ageing have a slight increase of 5.39% and 4.98%,respectively. The morphologies of fracture obtained by SEM show that the interface between fiber and matrix are not damaged obviously,and the aging process mainly occurres in the area of PA6 matrix. With longer aging time,the crystallinities of PA6/LGF composites decrease from 26.19% to 20.70%. While the crystallinities of PA6/LGF/ZnO composites filled with 6% ZnO only decrease from 22.92% to 21.34%,which means the more stable crystallization properties are achieved.