聚氨酯弹性体（PUE）一般由软段和硬段形成，软段通常为单一多元醇结构，硬段则由异氰酸酯与扩链剂反应形成。若使用两种结构明显不同的多元醇，可制备具有两种软段结构的三嵌段交叉PUE。由端羟基聚丁二烯（HTPB）、聚氧化丙烯二醇（PPG）分别与甲苯二异氰酸酯（TDI）反应合成聚氨酯预聚体，两种预聚体按配比混匀后由1，4-环己烷二甲醇（CHDM）扩链，制得系列三嵌段交叉PUE，并对PUE的结构、力学性能和热学性能进行表征。结果表明：PUE分子中由PPG、HTPB构成的软段总含量在54.2%~55.4%之间时，HTPB在软段中占比对PUE力学性能影响较大，并影响其微观结构。随着HTPB链段在软段中占比的增加，PUE的硬度、比强度、断裂伸长率均呈现先增后降趋势，当HTPB在软段中占比为20.18%时，PUE比强度达18.44 MPa/（g/cm³），断裂伸长率达404.6%，邵尔D硬度达32。

Polyurethane elastomer (PUE) is generally composed of soft and hard segments. The soft segment is usually a single polyol structure, and the hard segment is formed from the reaction of isocyanate and chain extender. If two kinds of polyols with obviously different structures are used, triblock cross PUE with two soft segment structures can be prepared. Polyurethane prepolymers were synthesized by the reaction of hydroxyl polybutadiene (HTPB) and polyoxypropylene glycol (PPG) with toluene diisocyanate (TDI), respectively. The two prepolymers were mixed according to the ratio and then expanded by 1,4-cyclohexanedimethanol (CHDM) to prepare a series of triblock cross PUEs. The structural, mechanical and thermal properties of PUE were characterized.The results showed that when the total content of soft segments containing PPG and HTPB in PUEs was among 54.2%~55.4%, the proportion of HTPB in soft segments had great influences on the mechanical properties and microstructure of PUEs. With the increase of the proportion of HTPB segment in the soft segments, the hardness, specific strength and elongation at break of PUEs first increased and then decreased. When the proportion of HTPB in the soft segment was 20.18%, the specific strength, the elongation at break,and the hardness of PUE reached 18.44 MPa/(g/cm³), 404.6% and 32 Shore D, respectively.