热氧老化对无铬鞣革物理性能的影响

Effects of thermal-oxidative aging on physical performance of chromium-free leathers

皮革在一定湿度下进行热氧作用后,组织结构会逐渐发生物理化学上的变化,致使皮革商品丧失使用价值。模拟热氧老化处理,测定老化前后无铬鞣革物理性能参数的变化,对比观察老化前后革内纤维组织的差别。试验发现:4种无铬鞣法的革坯在老化前后变化的趋势,难以用统一的规律描述。醛植结合鞣革老化后,抗张强度和撕裂强度增加,其它3种革强度下降;负荷伸长率、柔软度也有升降不同的差异;老化后皮革的收缩温度(Ts)和崩裂强度均下降;老化后合成鞣剂和植铝鞣法革坯的透水汽值增大,另外2种鞣法革坯的透水汽值下降。扫描电镜下发现,老化后革纤维规整性降低。

Under the thermal - oxidative aging in moist air the tissue structures of leather will gradually changes in physical and chemical performance and the leather goods will lost the use value eventually. Simulating thermal - oxygen aging treatment to chrome - free leather to test the change in physical properties of chrome - free leather. The leathers＇fiber tissue differences under scanning electron microscopy （ SEM ） before and after aging were contrasted, the results show that four kinds of chrome - free leather samples vary in change tendency, and it is difficult to use a unified pattern to describe. The tensile and tear strength of vegetable - aldehyde combining tanned leather increase after aging and that of other three combining tanned leathers decrease. The tensile elongation and softness of leathers also have different changes. Shrinkage temperature and bursting strength of leather sam- ples decrease after aging. The water vapor pe^qneability of syntaned leather and vegetable - aluminum salts tanned leather increase and that of the other two leathers decrease after the thermal - oxidative aging. SEM shows that the fibers regularity of all leather samples decreased after aging.