PCDL/MDI型热塑性聚氨酯弹性体的制备与性能

Preparation and Properties of PCDL/MDI Type Thermoplastic Polyurethane Elastomer

以聚碳酸酯二醇(PCDL)、4,4’-二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为原料,通过两步法制备了硬段含量分别为31%,38%,44%的PCDL/MDI型热塑性聚氨酯(PUR-T)弹性体,并利用拉力试验机,邵氏硬度计,X射线衍射仪,维卡软化点测定仪,动态流变仪和偏光显微镜等测试表征手段,对PUR-T弹性体的力学性能、耐热变形性能、动态流变性能以及结晶等进行了研究。结果表明,随着硬段含量的增加,PUR-T弹性体的硬度、拉伸强度和定伸应力均逐渐增大,而断裂伸长率呈下降趋势,其中当硬段含量为44%时,PUR-T弹性体的邵氏A硬度为91,拉伸强度达到24.78 MPa,300%定伸应力为12.40 MPa,而断裂伸长率为558.62%;X射线衍射图中只有宽的漫散射峰,没有锐的结晶峰,表明PUR-T弹性体呈无定形状态;PUR-T弹性体的硬段含量为31%时,维卡软化温度为83℃,而PUR-T弹性体的硬段含量为44%时,维卡软化温度达到128℃,抗热变形能力显著提高;PUR-T弹性体的熔体复数黏度均随着角频率的增加而下降,表现为剪切变稀现象,材料为假塑性流体,并且PUR-T弹性体的储能模量均随着温度的升高而降低;经过热处理后,PUR-T弹性体均有球晶生成,且结晶能力随硬段含量的增加而提高。

Using polycarbonate diol（PCDL）,4,4’-two phenyl methane diisocyanate（MDI） and 1,4-butane diol（BDO） as raw materials,a series of novel thermoplastic polyurethane（PUR-T） elastomer containing 33%,38%,44% hard segment were prepared by two-type method. The PUR-T elastomer properties such as mechanical properties,thermal deformation resistance, dynamic rheological properties and crystallization properties were tested by tensile testing machine,shore hardness tester,X-ray diffractometer,thermal deformation vicat point tester,dynamic rheometer,polarizing microscope,etc.. The results show that the hardness,tensile strength and stress at definite elongation of PUR-T elastomer increases when the content of hard segment increases, whereas the elongation at break decreases. Specifically,the PUR-T elastomer with 44%hard segment has the best comprehensive mechanical and physical properties with the shore A hardness being 91,the tensile strength being 24.78 MPa,the 300%stress at definite elongation being 12.40 MPa and the elongation at break being 558.62%. The wide diffuse scattering peaks are only observed in X-ray diffraction diagram,which show PUR-T elastomer are amorphous. The vicat softening temperature enhanced from 83℃ to 128℃,when the hard segment content changed from 31%to 44%,and the resistance to thermal deformation improved. The PUR-T elastomer melt is pseudo plastic fluid and all specimens exhibited shear thinning behavior. The storage modulus of PUR-T elastomer decreases as the temperature rises. The spherulites are generated after heat treatment and the crystalline ability of PUR-T elastomer improved with the increase of hard segment content.