退火对聚醚型TPU薄膜结构及性能的影响

Effect of Annealing on Structure and Properties of Polyether TPU Film

以聚醚型热塑性聚氨酯(TPU)为原料,采用模压成型工艺,在不同冷却速率下制备了系列TPU薄膜。分别在70、110、150℃温度条件下,对TPU薄膜进行退火热处理,利用原子力显微镜(AFM)、红外光谱仪(FTIR)、差示扫描量热仪(DSC)和电子万能拉力机对未处理的及退火后的TPU薄膜的微观形貌、结构、热性能及力学性能的变化进行表征和测试。结果表明,较低的成型冷却速率和退火处理能增大TPU薄膜的硬段相尺寸。退火工艺能提高TPU薄膜硬段的有序排列程度,并且,高温退火后,硬段形成微晶,氢键强度和拉伸强度降低,其中,在34.8℃/min冷速下成型的TPU薄膜,在150℃下退火10 h后,氢键强度和拉伸强度下降最显著,分别降低了5.11%和32.16%。

A series of TPU films were prepared using polyether thermoplastic polyurethane as raw material by molding process at different cooling rates.The TPU films were subjected to annealing heat treatment at 70,110 and 150℃,respectively,and the changes of microscopic morphology,structure,thermal and mechanical properties of TPU films before and after annealing were characterized and tested by atomic force microscopy,infrared spectroscopy,differential scanning calorimetry and electronic universal tensile machine.The results showed that the hard segment size of TPU films increased at a lower molding cooling rate and after annealing heat treatment.After annealing heat treatment,the degree of orderly arrangement of the hard segments of TPU films increased.After high temperature annealing,the hard segments formed microcrystals,and the hydrogen bonding degree and tensile strength reduced.In which,the hydrogen bonding degree and tensile strength of TPU films molded at 34.8℃/min cold rate decreased most significantly after annealing at 150℃for 10 h,decreasing by 5.11%and 32.16%,respectively.