有机硅/丁二醇扩链剂混合比对混合大二醇基聚氨酯弹性体的性能影响

以α,ω-双(γ-羟丙基)聚二甲基硅氧烷(BHPDMS)和聚氧四甲基二醇(PHMO)混合大二醇为软链段;以1,4-丁二醇(BDO)为主要扩链剂,1,3-双(4-羟丁基)-1,1,3,3-四甲基二硅氧烷(BHTD)为次级扩链剂,所有试样中硬链段均由4,4'-二苯基甲烷二异氰酸酯(MDI)和混合扩链剂所构成,且w(硬链段)=40%;采用两步溶液聚合法制备混合大二醇基芳香聚氨酯(PU)弹性体。通过力学性能测试、差示扫描量热法(DSC)和动力学热分析法(DMTA),研究了混合扩链剂中n(BDO)/n(BHTD)比值对该PU弹性体性能的影响。结果表明,当n(BDO):n(BHTD)=3:2时,所得PU弹性体具有优异的综合性能;引入BHTD扩链剂后,破坏了硬链段的有序性。

Effect of chain extender mixing ratio of organo silicone and butanediol on performance of polyurethane elastomer based on mixing macrodiol

With mixing macrodiol of α,ω-bis(γ-hydroxypropyl) polydimethylsiloxane(BHPDMS) and poly(hexamethyleneoxide)(PHMO) as soft segment,1,4-Butanediol(BDO) as primary chain extender,1,3-bis(4-hydroxybutyl) tetramethyldisiloxane(BHTD) as secondary chain extender,the hard segment in all samples derived from 4,4'-methylenediphenyl diisocyanate(MDI) and mixing chain extender,mass fraction of hard segment at 40%,the aromatic polyurethane(PU) elastomer based on mixing macrodiol was prepared by two-step solution polymerization.The Effects of molar ratio of BDO and BHTD in mixing chain extender on performances of the PU elastomer were studied by mechanical properties testing,differential scanning calorimetry(DSC) and dynamic mechanical thermal analysis(DMTA).The results showed that the PU elastomer has excellent integration performance when molar ratio of BDO and BHTD was 3:2,the order of hard segment in all cases was disrupted after BHTD chain extender was imported.