摘要
Sustainable polyurethanes prepared from castor oil and diisocyanates show very low strength and toughness, due to the highly cross-linked and flexible structure. Herein, we report a new strategy to simultaneously reinforce and toughen castor oil-based polyurethane via incorporating a stiff component （isosorbide, IS） to enhance network stiffness and reduce crosslink density. The crosslinking degree de- creases while the strength, moduli, ductility and heat re- sistance significantly increase accordingly with increasing IS content. The tensile behaviors are tunable over a broad range （either as elastomers or as plastics） depending on the com- positions. The polyurethanes show excellent thermal stability with onset decomposition temperature higher than 280℃. The investigation provides a new hint for future design and fab- rication of high performance sustainable polymers from other vegetable oils.
蓖麻油基聚氨酯(COPU)链柔顺性大且交联密度高,导致其力学强度与韧性俱差.本文将双官能度刚性物质引入COPU,一方面,利用其刚性增强COPU的力学强度与模量;另一方面,利用双官能度结构,降低COPU的交联密度,提升其韧性,同时实现COPU的增韧与增强.我们将生物基异山梨醇(IS)用作COPU的结构调节单元,设计合成了一系列生物基聚氨酯(CIPU).研究发现:当IS含量较少时,CIPU表现出弹性体的拉伸行为,其拉伸强度与断裂伸长率均随IS含量增加而大幅增加;当IS含量高于蓖麻油时,CIPU表现出塑料的拉伸行为,拉伸强度与断裂伸长率分别可达~34 MPa与~200%,为COPU的44与5倍.此外,该CIPU还表现出优异的热稳定性与耐热性.该研究可为植物油基高分子新材料的设计合成提供借鉴.
基金
supported by the National Natural Science Foundation of China (51703188)
the Basic and Frontier Research Project of Chongqing (cstc2017jcyj AX0426)
the Fundamental Research Funds for the Central Universities (XDJK2017A016 and XDJK2017C022)
