Effects of thermal-oxidative aging on static and dynamic mechanical properties of long glass fiber reinforced nylon 10T composites
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摘要: 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50 d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。Abstract: 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/PA10T composites were characterized by DSC, DMA, SEM and mechanical properties test, and the activation energy of glass transition of LGF/PA10T composites were calculated. The results indicate that PA10T molecular 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/PA10T composites are 4.9%, 6.3% and 9.4%, respectively. With the increase of aging time, the interfacial interaction between glass fiber and PA10T 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 PA10T molecular chain changed and reduce the thermal stability of LGF/PA10T composites.
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Keywords:
- thermal-oxidative aging /
- long glass fiber /
- nylon10T /
- mechanical properties /
- activation energy
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