【摘要】 使用QUV紫外耐候试验机进行老化实验,研究了高温高湿环境下紫外老化对氨纶力学性能及微观结构的影响,通过傅立叶变换红外光谱（FTIR）、差示扫描量热、X射线衍射及力学性能分析探究氨纶紫外老化规律及机理,结果表明:随老化时间增加,N—H基氢键化程度变大,C—N键断裂,侧链上甲基脱氢变为更加活泼的亚甲基;氨纶热性能不断下降,玻璃化转变温度（Tg）不断升高且微相分离程度变差;结晶度在老化初期变化较小,呈先增后减的趋势,在老化150 h达到峰值。紫外老化后的氨纶,断裂伸长率及断裂强力在老化初期（0⁵0 h）下降明显,随后缓慢上升,分别在200 h及150 h骤降;老化前后氨纶弹性模量与结晶度变化趋势近似,弹性模量先增后减,在老化100 h达到峰值,300%弹性回复率不断下降。FTIR图谱1 110 cm^-1处显示氨纶老化前后醚基无显著变化,而1 710 cm^-1处样品吸水后产生的C=O基峰及3 317 cm^-1处因紫外光照C—N键断裂而引起的N—H吸收峰明显变弱,证明氨纶紫外老化本质是紫外光解及水解的协同作用,温度起到加速老化作用。更多还原

【Abstract】 Aging experiments of spandex was carried out under different condions in QUV aging machine,while the influence of UV aging time on structure and properties of spandex under high temperature and high humidity was obtained with analysis of Fourier transform infrared spectroscopy（FTIR）,differential scanning calorimeter,X-ray diffraction and mechanical tests. The results show that with the increase of aging time,the hydrogen bonding degree of N—H groups became larger and C—N bonds broke down while the methyl dehydrogenation converted to methylene. Thermal properties of spandex declined continuously,while Tg increase and the microphase separation degree become worse. Crystallization degree of spandex has little change during early period,which increase until 150 h and then decrease. The elongation at break and breaking strength of UV-aged spandex decrease significantly at the beginning of aging（0-50 h） and then slowly increase at 200 h and 150 h respectively. The elastic modulus show similarly trend with crystallinity degree of spandex,which increase until 100 h and then decrease,while the rate of 300% elastic recovery decrease continuously. Furthermore,ether group show no significant change at 1 110 cm^-1 while the C=O peak caused by water is emerged at 1 710 cm^-1 and the N—H peak is weaker at 3 317 cm^-1 due to breakup of C—N from aged and unaged FTIR,which show UV and water dominate during the aging period while aging progress can be accelerated under experiment temperature.更多还原