CTO/PCL-3057共混软段聚氨酯弹性体的相分离和力学性能

Phase Separation and Mechanical Properties of Polyurethane Elastomer with Blended CTO/PCL-3057 Soft Segment

以蓖麻油(CTO)/聚己内酯三醇(PCL-3057)共混物为软段,三羟甲基丙烷为小分子交联剂,与多亚甲基多苯基多异氰酸酯(PAPI)反应,制备了软段中CTO质量分数分别为30%、50%、60%、70%和100%的聚氨酯弹性体(PUE),研究软段组成对PUE相分离结构和力学性能的影响。结果表明:CTO主要促进硬段之间氢键的形成,PCL-3057主要促进软硬段之间氢键的形成;两者各占50%时,PUE结晶性好,氢键度大,微相分离程度较完善,交联程度适当,所以力学强度高且韧性好。CTO柔顺性好,可以降低PUE软段的玻璃化转变温度(T_(gs)),而PCL-3057中极性基团过多会降低T_(gs);两者各占50%时,T_(gs)最大。PCL-3057都能显著提高PUE的动态力学性能。

Polyurethane elastomers(PUE)with castor oil(CTO)mass fractions of 30%,50%,60%,70%,and 100%were prepared using a blend of CTO and polycaprolactone terpolymer(PCL-3057)as soft segments,trimethylolpropane as crosslinking agent,and reacting with polymethylene polyphenyl polyisocyanate(PAPI).The influence of soft segment composition on the phase separation structure and mechanical properties of PUE was studied.The results indicated that the formation of hydrogen bonds between hard segments was mainly promoted by CTO,while the formation of hydrogen bonds between soft and hard segments was mainly promoted by PCL-3057.When the content of both accounted for 50%,PUE had good crystallinity,high hydrogen bonding degree,complete microphase separation,and appropriate crosslinking degree,resulting in high mechanical strength and good toughness.The glass transition temperature(Tgs)of PUE soft segment could be reduced by CTO with good flexibility,while it could be reduced by excessive polar groups in PCL-3057.When the content of both groups accounted for 50%,Tgs was the highest.The dynamic mechanical properties of PUE could be significantly improved by PCL-3057 at both low and high temperatures.