聚合级碳化二亚胺的合成及湿热老化研究

Synthesis and Hygrothermal Aging of Polymer Carbodiimides

使用2,4,6-三乙基-1,3-苯二胺和三光气为原料,采用异氰酸酯法合成聚三乙基-1,3-苯碳化二亚胺(PAH),经过两步反应后最终得率为66%。用红外和核磁共振进行了结构分析,PAH具有明显的碳化二亚胺结构。通过DSC和TG对PAH抗水解剂的熔点和耐热性能进行了系统评价,PAH没有明显熔点,是一种非晶聚合物,熔程为125~144℃,高于单体碳化二亚胺;热失重分析PAH,在500℃下的热失重仅为51%,而单体碳化二亚胺已完全挥发。PAH的高耐热性使其在母料和薄膜加工过程中,挥发和热降解更少,颜色更浅,对母料的黏度提升更大,具有更好的耐水解性能,薄膜在湿热老化48 h的断裂伸长保持率可达62.9%。

Polymer carbodiimides(PAHs)were synthesized by the isocyanate method with 2,4,6-triethyl-1,3-phenylenediamine and triphosgene as raw materials.After two-step reaction,the yield rate of PAHs was 66%,which had a distinct carbodiimide structure.The PAH’s melt point and heat resistance were evaluated by DSC and TG.PAHs were a kind of amorphous polymers without obvious melt points,and their melting range was from 125℃to 144℃,which was higher than that of haplotype carbodiimides.Thermogravimetric analysis showed that the weight loss of PAHs at 500℃was 51%,compared with the haplotype carbodiimides which was completely volatilized.The high heat resistance of PAHs made it less volatilization and thermal degradation,lighter color,greater increase in viscosity of the masterbatch and better hydrolysis resistance in the process of masterbatch and film processing,so that the retention rate of elongation at break of the films was up to 62.9%after 48 hours of wet and heat aging.