聚氨酯弹性体结构对阻尼性能及力学性能的影响

Effects of structure on damping properties and mechanical properties of polyurethane elastomers

以不同相对分子质量的聚氧化丙烯二醇(PPG)为软段,不同异构体的二苯基甲烷二异氰酸酯(MDI)、甲苯二异氰酸酯(TDI),以及扩链剂新戊二醇(NPG)、三羟甲基丙烷(TMP)、1,4-丁二醇(BDO)为硬段,采用预聚法合成了聚氨酯弹性体,并对其损耗因子(tanδ)与力学性能进行了测试。结果表明:随着4,4'-MDI含量的增加,聚氨酯弹性体的tanδ曲线峰高降低,即阻尼性能下降,力学性能提高;随着2,4-TDI含量的增加,阻尼性能提高,力学性能降低;扩链剂TMP含量增加,tanδ峰向高温方向移动;扩链剂NPG含量增加,阻尼性能提高;软段相对分子质量增大,tanδ峰向低温移动,PPG相对分子质量从400增加到2 000时,tanδ峰的位置从80℃变化到-20℃左右。

Polyurethane （PU） elastomers were synthesized from polyether-diol （PPG） with different relative molecular mass as a soft segment, different isomer methylenebis （phenyl isocyanate） （MDI） or toluene diisocyanate （TDI）, and chain extender neopentyl glycol （NPG）, tri （hydroxymethyl） propane （TMP） and 1,4-bntanediol （BDO） as hard segments by two-step bulk polymerization process. The loss tangent （tan~） and mechanical properties of the PU elastomers were tested. The results indicate that the peak of the tanc~ curve of the PU elastomers lowers, and there- fore the damping properties of the PU elastomers are weaken and the mechanical properties of the PU elastomers are enhanced with increasing the content of 4,4＇ -MDI isomer. The PU elastomers ＇ damping properties improve while theirmechanical properties decline with the rise in the content of 2,4-TDI isomer. The tang peak of the PU elastomers moves towards the high-temperature end with the augmentation of the content of chain extender TMP. The damping properties are improved with the increase in the content of chain extender NPG. The tang peak of the PU elastomers moves to the low-temperature end with raising the relative molecular mass of the soft segment. The tang peak shifts from 80 ℃ to about -20 ℃ when the relative molecular mass of PPG rises from 400 to 2 000.