硫酸钡填充热塑性聚氨酯弹性体的热性能研究

Thermal Behaviour of BaSO_4-Filled Thermoplastic Polyurethane Composites

通过Brabender塑性仪熔融挤出硫酸钡（BaSO4）填充的聚醚型聚氨酯弹性体（PO-TPU）、聚酯型聚氨酯弹性体（PE-TPU）复合材料。凝胶渗透色谱（GPC）和热失重分析（TG）研究表明，BaSO4的存在催化了热塑性聚氨酯弹性体（TPU）热降解。相对于纯PO-TPU挤出，PO-TPU／BaSO4的数均相对分子质量M^-a减少了13．4％，重均相对分子质量M^-w减少了32．6％；相对于纯PE-TPU挤出，PE-TPU／BaSO4的M^-n减少了34．5％，M^-w减少了51．6％。在大约320℃之前，BaSO4填充的TPU具有更大的质量损失速率，且对PE-TPU影响尤为明显。相应的力学性能测试表明，TPU／BaSO4复合材料表现出更大的降低幅度。这显示了BaSO4加速了TPU的分解，对分解过程起到了催化促进作用。

Polyether and polyester thermoplastic polyurethane-BaSO4 composites were prepared in a Brabender Plasticorder by melt mixing, their thermal stabilities were studied through GPC and TGA measurements. Due to the catalysis of barium sulfate, the number- and weight average molecular weight of PO-TPU/BaSO4 decreased 13.4 % and 32.6 %, respectively, during the extrusion compared with neat PO-TPU; those of PE-TPU/BaSO4 decreased 34.5 % and 51.6 % compared with neat PE-TPU. In the TG analysis, BaSO4-filled thermoplastic polyurethane displayed higher rates of mass loss below 320 ℃, especially in the case of PE-TPU. BaSO4 also caused larger loss in mechanical properties due to accelerated decomposition.