草酸稀溶液高效分离废旧聚酯/棉混纺织物

针对废旧纺织品循环利用中聚酯纤维、棉纤维混纺纱线结构紧密缠绕,难以分离而无法加工的问题,采用环境友好的草酸体系选择性水解混纺织物中的棉纤维,从而释放聚酯纤维实现有效分离,并对草酸体系分离工艺进一步优化。研究表明:与无机酸相比,在相同反应条件下,草酸可达到与盐酸相当的分离效果且所得聚酯纤维形态更完整,棉纤维水解程度更低,水解产物分布更窄;在草酸浓度为0.07 mol/L、反应温度为130℃、反应时间为3 h的条件下,聚酯/棉混纺织物的分离效果最优;其中棉纤维水解为纤维素材料,得率为91.46%,另有小部分水解为葡萄糖或低聚糖;聚酯纤维回收率高达99.28%,且保留了原有聚酯纤维的性能,可直接生产加工;该反应体系可循环利用多次,实现了废旧聚酯/棉混纺织物的高效综合利用。

Efficient separation of polyester and cotton from waste blended fabrics with dilute oxalic acid solution

In view of the problem that tightly twisted polyester and cotton fibers in blended yarns are difficult to separate and hence unable to be processed in the recycling of waste textiles,an environmentally friendly oxalic acid system was used to selectively hydrolyze the cotton fiber of blended fabric hence releasing the polyester fiber to achieve effective separation.The conditions of oxalic acid treatment were further optimized.The results show that oxalic acid can achieve the same separation effect as hydrochloric acid under the same reaction conditions,and the morphology of polyester fiber is more complete,the hydrolysis degree of cotton fiber is lower and the distribution of hydrolysate is narrower.When the oxalic acid concentration is 0.07 mol/L,the reaction temperature is 130℃and the reaction time is 3 h,the separation effect of polyester and cotton in the blended fabric reach the best level,where the yield of cotton fiber hydrolyzed into cellulose reaches 91.46%,with a small part being hydrolyzed into glucose or other oligosaccharides.The recovery ratio of polyester fiber is as high as 99.28%,retaining the original physical and chemical properties,which can be directly processed for textile production.The reaction system can be used for many times,facilitating the high efficiency and comprehensive utilization of waste polyester/cotton blended fabrics.