不饱和聚酯玻璃钢的加速老化研究.pdf

南昌航空大学硕士学位论文不饱和聚酯玻璃钢的加速老化研究姓名：朱春芽申请学位级别：硕士专业：材料加工工程指导教师：赵晴20080601I摘 要本文通过氙灯人工加速老化、热氧人工加速老化和西部自然大气老化试验，研究了 191#不饱和聚酯玻璃钢及纯树脂的老化行为和规律测试了试样的弯曲强度、层间剪切强度和冲击韧性随老化时间的变化；研究了滑石粉填料对玻璃钢老化行为的影响；研究了环境因素对玻璃钢及纯树脂表面光泽度、黄色指数及表面微观形貌的影响； 用动态力学分析(DMA)研究了老化前后纯树脂的动态力学性能氙灯老化辐照强度为 1000±200W/m2，温度 40℃，喷淋周期 18min/102min（喷淋/不喷淋） 随着老化时间的延长，纯树脂的弯曲强度先增大后减小，2100h后弯曲强度下降了 6.5%；玻璃钢弯曲强度呈增大趋势，1800h 后强度增大 17%，玻璃纤维增强了玻璃钢的耐老化性；有填料的玻璃钢弯曲强度先增大后减小，1800h 后强度下降 7.8%；无填料和有填料玻璃钢的层间剪切强度下降均很明显，1800h 后分别下降 42.7%和 46.2%；玻璃钢的冲击韧性变化不大；无机填料降低了玻璃钢的耐光氧老化性能。

老化后试样表面产生大量裂纹，光泽度下降幅度大，2100 小时后纯树脂和玻璃钢的失光率分别为 86%和 91%纯树脂的 DMA 表明：1800h 后高弹态储能模量下降了 21%，树脂发生了少量降解；Tg由 85℃上升到89℃，分子链链段的运动能力下降70℃热氧老化 5600h 内，纯树脂及玻璃钢呈现明显的强度增大、韧性下降趋势5600h 后玻璃钢的弯曲强度和层间剪切强度均增大 50%左右，冲击韧性下降了 14.3%；填料对玻璃钢的热氧老化性能影响不大；试样的表面形貌和光泽度变化较小，但变黄现象明显DMA表明：3600h 后纯树脂高弹态储能模量变化不大 ；玻璃态储能模量增大，刚度增大；Tg 从 85℃升高到 88℃玻璃钢在拉萨、尉犁、江津和武汉四个曝晒点自然老化一年后的拉伸、弯曲和层间剪切强度呈增大趋势；拉萨和尉犁的强辐射和干旱气候使玻璃钢的弯曲和层间剪切强度提高较明显； 武汉和江津的高温湿热环境对玻纤/树脂界面结合性能影响较大；自然老化后玻璃钢的表面光泽度和形貌变化不大DMA 表明：拉萨太阳辐射强度和辐照量大，则纯树脂的高弹态储能模量下降的程度越大；老化后几个地区纯树脂的 Tg 均有提高，但相差不大。

研究表明：191#不饱和聚酯玻璃钢具有较好的耐大气老化性能；老化对玻璃钢力学性能影响最大的是层间剪切强度；光是引起树脂降解的主要因素；光、热和水的协同作用是玻璃钢表面和玻纤/树脂界面老化破坏的主要影响因素关键词：不饱和聚酯玻璃钢，人工加速老化，自然大气老化，机械性能，DMAIIABSTRACTIn this paper, the behavior and rule of aging about glass fiber reinforced 191# unsaturated polyester composites (191-FRP) and pure resin were studied by means of three kinds of aging tests: artificial accelerated xenon weathering aging, artificial accelerated thermal oxidative aging and natural weathering aging in western China. Change in bending strength, interlaminar shear strength (ILSS) and impact toughness of the samples with aging time was tested. The influence of talcum powder filler on the behavior of aging about 191-FRP was also studied. The effect of the weathering factors to the luster, yellow index and micro-morphology on the surface of pure resin and 191- FRP was analysed. Observe the dynamic mechanical property of pure resin before and after aging according to dynamic mechanical analysis (DMA). The radiation intensity of xenon lamp is 1000±200W/m2.Testtemperature is 40℃. The period of spray is 18min/102min (spray water /no spray water). The bending strength of pure resin exhibited increasing than decreasing trend with the aging time, dropping 6.5% after 2100h; However,bending strength of 191-FRP displayed increasing tend with rising 17% after 1800h, which indicated glass fiber enhanced the aging resistance of 191-FRP; The bending strength of 191-FRP filled with filler exhibited increasing than decreasing trend with dropping 7.8% after 1800h. There was a quite evident decreasing in the ILSS of 191-FRP unfilled and filled with filler, dropping respectively 42.7% and 46.2% after 1800h; However, the impact toughness of 191-FRP changed little after aging; Filler weakened the resistance to photo-oxidizing aging of 191-FRP; There were lots of microcracks occurring and a great falling of luster on the surface of aged specimens. The rate of luster loss of pure resin and 191- FRP were respectively 86% and 91% after 2100h. DMA of pure resin shows: after aging for 1800h, the storage modulus(E') of pure resin at the rubbery state decreased 21% implying degradation of resin to some extent; The glass transition temperature(Tg) increased from 85℃ to 89℃ indicating a decreased mobility of molecular segmer of resin. During 5600 hours thermal oxidative aging at 70℃, The bending strength and ILSS of 191-FRP chiefly presented increasing trend withincreasing about 50% but impact toughness decreasing trend with decreasing 14.3%. Filler slightly effected on the resistance to thermal oxidative aging of 191-FRP. Thermal oxidition made little effect on the surface morphology and luster of specimens, but the change of yellow index was obvious. DMA shows: there was no obvious phenomenon to change the E' of resin at the rubbery state; The E' at the glassy state improved, which implied the increased rigidity; The Tg increased from 85℃ to 88℃. The tensile strength, bending strength and ILSS of 191-FRP after aging for one year in four national testing fields—Lasa, Weili, Jiangjin and Wuhan exibited increasing trend. The strong light radiation and arid weathering in Lasa andWeili contributed to improving the bending strength and ILSS of 191-FRP; High temperatureIIIand muggy weathering in Wuhan and Jiangjin made effect on glass fiber/resin matrix interface in evidence. The change of luster and micro-morphology on the surface of 191-FRP after nature aging was not evident. DMA shows that there was more decrease of E' at the rubbery state of pure resin aged at Lasa as more exposure and intensity of radiation in Lasa; Tg of pure resin aged in four testing fieldsincreased somewhat, but the variance was not evident. The research shows that 191-FRP is a kind of excellent material resisting to weathering aging; The most obvious change of mechanical strength after aging of 191- FRP is ILSS. The radiation of light is the main factor resulting in degradation of resin. The combination bet。