海洋工程材料团队
[研究进展]颉康洲同学提出了一种以可再生尿素和二胺为原料,以环氧(1,4-丁二醇二缩水甘油醚)和烷基双脲(BUs)为原料制备聚氨酯玻璃体的新方法。
发布时间: 2022-04-13 浏览次数: 21

Title:  A Nonisocyanate Strategy toward Polyurethane Vitrimers from Alkylene Bisurea and Epoxide through Eutectic-Assisted Melting.




Abstract: Nonisocyanate polyurethanes (NIPUs) are nowadays considered as green  alternatives to conventional polyurethanes, without using the toxic  isocyanates. NIPUs usually are synthesized from cyclic carbonates and  di(poly)amines. Herein a novel pathway toward polyurethane vitrimers  (PUVs) based on epoxide (1,4-butanediol diglycidyl ether, BDE) and  alkylene bisureas (BUs) is reported, which can easily be prepared from  renewable urea and diamines. Due to the high melting temperature and the  poor solubility, BUs are rarely applied in the synthesis of  polyurethanes. To enhance the mellability of BUs, ZnCl2 is introduced to form eutectic system and therefore to assist melting of BUs (eutectic-assisted melting). When 100 mol% of ZnCl2  is added, BUs are able to melt at 130 °C at which polymerization  between BUs and BDE is then triggered and can be finished within 10 min.  Interestingly, the obtained polymers are found to be polyurethane  vitrimers, for which the relationship between the relaxation time (τ*) and the temperature (T)  fits with Arrhenius equation. PUV-10 samples before and after  reprocessing remains similar appearance and mechanical properties (E: ≈90 MPa; σb: ≈17 MPa; εb: ≈200%). A new synthetic strategy is apparently offered here for NIPUs and even for PUVs without adding any crosslinker.