低分子量HTPB聚氨酯弹性体的制备及其性能

为改善高固含量高聚物黏结炸药(PBX)和丁羟推进剂的工艺性能,以低分子量的端羟基聚丁二烯(HTPB)、异佛尔酮二异氰酸酯(IPDI)为主要原料,选用一缩二乙二醇(DEG)为扩链剂,采用二步法制备了聚氨酯弹性体。研究了催化剂用量对浆料黏度的影响,固化参数R及扩链剂用量对HTPB聚氨酯弹性体力学性能的影响。试验结果表明,当催化剂质量分数为0.004%时,适用期可达5 h;R值为1.1,DEG羟基含量占反应总羟基量的60%时,聚氨酯弹性体力学性能较好,拉伸强度达7.60 MPa,断裂伸长率达540.21%。动态力学分析(DMA)测试结果显示,低分子量HTPB聚氨酯弹性体有两个明显的玻璃化转变温度,说明样品存在明显的微相分离结构。

Preparation and Properties of Polyurethane Elastomers Containing Low-molecular Weight HTPB

In order to improve the process performance of polymer bonded explosive (PBX) with high solid content and HTPB propellant,the polyurethane elastomer was prepared by two-step method,using low-molecular weight hydroxyl terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI) as the main ingredient,and diethylene glycol (DEG) as chain extender.Effect of catalyst dosage on the viscosity of slurry,and influence of curing parameters R and chain extension agent dosage on the mechanical properties of HTPB polyurethane elastomer were studied.Results show that the pot-life is 5 h at 0.004％ mass fraction of catalyst;and the polyurethane elastomer exhibits good mechanical properties with tensile strength of 7.60 MPa,elongation of 540.21％ at an R value of 1.1 and DEG mass fraction of 60％.Results of dynamic mechanical analysis (DMA) show that there are two distinct glass transition temperatures in the low-molecular weight HTPB polyurethane elastomers,which shows that the sample has obvious microphase separation structure.