HQEE扩链聚氨酯弹性体的形态结构及动态流变行为

针对推进剂粘合剂的需要,采用熔融预聚二步法合成了以环氧乙烷/四氢呋喃无规共聚醚(PET)为软段、间苯二亚甲基二异氰酸酯(XDI)和对苯二酚-双(β-羟乙基)醚(HQEE)为硬段的热塑性聚氨酯弹性体(TPU),采用动态流变行为分析,红外光谱(FTIR),广角X射线分析(WAXD),动态热机械分析(DMA),凝胶渗透色谱(GPC)和硝化甘油吸收等分析技术对TPU的结构、性能和动态流变行为进行研究。结果表明,TPU的储能模量、损耗模量、复数黏度随硬段含量增加而增大,硬段含量为45%的TPU具有最佳的复数黏度,具有典型的微相分离特征和聚醚聚氨酯的结构特征,具有较低的软段玻璃化转变温度和较高的相对分子质量,以及与硝酸酯良好的相容性,并且所有硬段含量的TPU均无明显的结晶形态。

Morphology and Dynamic Rheological Behaviors of Thermoplastic Polyurethane Based on HQEE as Extender

According to the requirement of propellant binder,a series of novel segmented thermoplastic polyether polyurethane elastomers(TPU) based on tetrahydrofuran-ethylene oxide copolyether(PET) as the soft segments and 1,3-bis(isocyanatomethyl)benzene(XDI) extended with hydroquinone-bis(β-hydroxyethy)ether(HEQQ) as the hard segments were synthesized to study the relationships between morphology and properties.The experimental techniques utilized were dynamic rheological behaviors,FTIR,WAXD,DMA,GPC and the miscibility with nitrate ester.The results show that the storage modulus(G′),loss modulus(G″)and the complex viscosity(η*) of the blends increase gradually with increasing fraction of hard segment content,and the TPU has a higher molecular weight with polyurethane characterization and typical microphase separation,and exhibits excellent the complex viscosity of TPU with 45% hard segment contents to meet requirements of propellant in terms of lower Tg of soft segments,good miscibility with nitrate ester,while the strain decreases WAXD results indicate that all elastomers are completely amorphous at all levels of hard-segment concentration.