不同软段相对分子质量对PBA/MDI/HG体系TPU结构与性能的影响

Characterization and properties of thermoplastic polyurethane elastomer in PBA/MDI/HG system with different soft segment of molecule weight

以聚己二酸-1,4-丁二醇酯二醇(PBA)、4,4′-二苯基甲烷二异氰酸酯(MDI)和1,6-己二醇(HG)等为主要原料,采用预聚体法制备了一系列热塑性聚氨酯弹性体(TPU)。通过对TPU流变性能、结晶性能、耐热性能、硬度与力学性能的研究,考察了在硬段含量相同(质量分数为30%)情况下,不同软段相对分子质量(PBA:1 000、2 000、3 000)对TPU体系结构与性能的影响。结果表明,PBA/MDI/HG体系TPU,随着软段PBA相对分子质量的增大,拉伸强度、断裂伸长率及硬度逐渐增大;TPU热稳定性越来越好,PBA-3000的TPU试样初始分解温度达到293.7℃;TPU抗热变形能力增强,PBA-3000的TPU试样维卡软化温度达到103℃;结晶性能分析(广角X射线衍射仪、旋转流变仪、偏光显微镜)表明,TPU具有一定的结晶性,且结晶性能随软段相对分子质量的增大而提高;流变性能分析结果表明,TPU表现出典型的假塑性流体的特征,且软段相对分子质量越大,同频率时的复数粘度越高。

In this paper,different thermoplastic polyurethane elastomer were prepared by poly-1,4-butylene adipate glycol（PBA）,methylene diphenyldiisocyanate（MDI）and 1,6-hexanediol（HG）.The effects of the different soft segment of molecular weight,while the same hard segment content,on the structures and properties of TPU were systematically studied by means of tensile testing,shore hardness testing,rotational rheometer,TG,X-ray testing,etc.The results showed that with the increase of molecular weight,the tensile strength,the elongation at break and the shore hardness increased obviously;the thermal stability and the deformation resistance ability of TPU got better：The initial decomposition temperature of TPU（the PBA molecular weight was 3000）reached 293.7 ℃.The vicat softening temperature of TPU（the PBA molecular weight was 3000）reached 103℃.The crystallization analysis showed that TPU could crystallize better when the PBA molecular weight was larger.Rheological analysis results showed a typical pseudo-plastic fluid characteristics.