可持续蓖麻油基聚氨酯的设计合成:同时实现增强与增韧(英文)

Rational design of sustainable polyurethanes from castor oil: towards simultaneous reinforcement and toughening

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.

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.