热氧老化对长玻纤增强尼龙10T复合材料静动态力学性能的影响

Effects of thermal-oxidative aging on static and dynamic mechanical properties of long glass fiber reinforced nylon 10T composites

通过熔融共混法制备出长玻纤增强尼龙10T(LGF/PA10T)复合材料,并且采用DSC、DMA、SEM和力学性能测试等方法研究了不同热氧老化时间对LGF/PA10T复合材料静、动态力学性能的影响,并对LGF/PA10T复合材料发生玻璃化转变时所需活化能进行了计算。结果表明:虽然在老化初期PA10T分子链之间会发生微交联,材料的刚性略有增加,但在整个老化过程中,分子链断裂、分子量下降起主导作用,在240℃下老化50d后,LGF/PA10T复合材料的拉伸强度保持率、弯曲强度保持率、缺口冲击强度保持率分别为4.9%、6.3%、9.4%。随着老化时间的增长,玻纤与PA10T基体之间的界面粘接作用减弱,玻璃化转变温度和阻尼性能下降。活化能计算结果表明热氧老化能够改变PA10T分子链的活动能力,降低了LGF/PA10T复合材料的热稳定性。

Long glass fiber reinforced nylon10T（LGF/PA10T）composites were prepared by melt blending method,and the effects of different thermal-oxidative aging time on the static and dynamic mechanical properties of LGF/PA10 Tcomposites were characterized by DSC,DMA,SEM and mechanical properties test,and the activation energy of glass transition of LGF/PA10 Tcomposites were calculated.The results indicate that PA10 Tmolecular chains are a little cross-linked in the initial stage of aging,slightly increasing the rigid properties of material,but the molecular chains fracture and the reduction of molecular weight play a vital role in the whole aging process.After aging at 240 ℃for 50 d,the tensile strength retention rate,flexural strength retention rate and notch impact strength retention rate of LGF/PA10 Tcomposites are 4.9%,6.3% and 9.4%,respectively.With the increase of aging time,the interfacial interaction between glass fiber and PA10 T matrix is weakened,both of the glass transition temperature and damping capacity decrease.The calculation results of activation energy show that thermal-oxidative aging can make the mobility of PA10 T molecular chain changed and reduce the thermal stability of LGF/PA10 Tcomposites.