浇注型端羟基聚丁二烯聚氨酯弹性体的合成及性能研究

Synthesis of Castable HTPB Polyurethane and its Properties

采用不同分子量的端羟基聚丁二烯（ＨＴＰＢ）和甲苯二异氰酸酯为主要原料合成预聚物，以Ｎ，Ｎ－Ｍ（２－羟丙基）苯胺为扩链剂制备了浇注型聚氨酯弹性体，并着重研究了预聚体中游离异氰酸酯基含量、扩链剂用量、ＨＴＰＢ分子量以及不同分子量ＨＴＰＢ并用和扩链剂并用对弹性体力学性能的影响，还对弹性体的结构与形态进行了初步分析和探讨。结果表明，预聚体中游离异氰酸酯基含量为９．０％时，拉伸强度最大，且综合性能最佳；扩链系数为０．８９时，拉伸强度、定伸应力、硬度出现最大值；ＨＴＰＢ分子量增大，弹性体力学性能有下降趋势，不同分子量ＨＴＰＢ并用时分子量大的ＨＴＰＢ增多，力学性能下降；当ＨＴＰＢＭｎ＝３１００，游离异氰酸酯基含量为９．０％，扩链系数为０．８９时，弹性体综合性能最佳。电子显微镜照片显示ＨＴＰＢ型聚氨酯有微相分离，且软硬键段分布不规整。

A prepolymer was prepared using hydroxy--terminated polybutadienes (HTPB)with different molecular weight and 2, 4--toluene diisocyanate. A castable polyurethane was prepared with the said prepolymer and N,N--his (2--hydroxypropyl) aniline chain extender. The influence of the free isocyanate content in the prepolymer,the extender level,the molecular weightof HTPB,the blend of HTPB with different molecular weight and the blend of various chain extenders on the mechanical properties of the resultant elastomer were investigated. The structureand morphology of the elastomer were preliminary analysed and discussed. The results showedthat the maximum tensile strength and the optimum comprehensive properties were obtainedwhen the free isocyanate content in the prepolymer was 9. 0%; the maximum tensile strength,modulus and hardness were obtained when the chain extension coefficient was 0. 89;the mechanical properties of the elastomer decreased as the molecular weight of HTPB increased. It wasshowed by TEM that there were micro--phase seperation and irregular distribution of soft andhard blocks in HTPB polyurethane.