硬段调控对PPG-MDI型阻尼聚氨酯力学和热稳定性能的影响

Effects of hard segment regulation on mechanical property and thermal stability of PPG-MDI polyurethane

利用二甲苯二异氰酸酯(MDI)、聚丙二醇(PPG)、二甲硫基甲苯二胺等为原料制备硬段质量分数分别为20%、30%、40%和50%的聚氨酯(PU)样品,利用傅里叶变换红外光谱(FTIR)研究其结构组成和微相分离,热重分析(TGA)和差式扫描量热仪(DSC)分析其热性能和结晶性能,动态力学分析(DMA)研究样品的力学性能和阻尼因子(tanδ)。结果表明:PPG与MDI合成的PU并未产生结晶,硬段含量的增加会提高PU的微相分离程度和拉伸强度,但阻尼因子明显降低。其中PU-50的拉伸强度达到17.27 MPa,约为PU-20的26倍。而PU-20的阻尼因子峰值达到1.01左右,硬段含量对聚氨酯的力学性能和阻尼性能均存在较大影响。

Diphenylmethane diisocyanate(MDI),polypropylene glycol(PPG),dimethylthiotoluene diamine and other raw materials were used to prepare samples with hard segment mass fractions of 20%,30%,40%and 50%respectively.Fourier transform infrared spectroscopy(FTIR)was used to study the structure,composition and microphase separation of the samples.The thermal and crystallization properties were analyzed by thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).The mechanical and damping properties were tested by dynamic mechanical analysis(DMA).The results show that the polyurethane(PU)synthesized by polypropylene glycol(PPG)and methylenediphenyl diisocyanate(MDI)produces no obvious crystallization.With the increase of hard segment content,the microphase separation degree and tensile strength of PU increase,but the damping factor decreases noticeably.The tensile strength of PU-50 is 17.27 MPa,26 times of that of PU-20,and the peak value of the damping factor of PU-20 is about 1.01.The test shows that the content of hard segment has a great influence on the mechanical and damping properties of polyurethane.