Abstract: In order to optimize the mechanical properties and wettability of polyurethane nanofiber microporous membrane, polyurethane (PU) was synthetised with polytetrahydrofuran ether glycol (PTMG), 4,4′-methylene bis (phenyl isocyanate)(4,4′-MDI) and 1,4-butanediol (BDO) as the main raw materials. Then nanofiber membranes were prepared by electrospinning. The effects of different chain extension reaction times on the physical properties and fiber membrane properties of synthetic polyurethane were studied. The structure and morphology of PU were characterized by infrared spectrometer (FTIR), gel permeation chromatography (GPC), thermogravimetric analyzer (TG), scanning electron microscope (SEM) and dynamic/static contact angle analyzer. The results showed that the thermal stability of the synthesized polyurethane slightly increased and the film forming performance of the nanofibers increased with the increase of the molecular weight of the polyurethane when the chain expanding reaction time increased from 90 min to 120 min. When the chain extension reaction time was 120 min, the breaking stress of the fiber membrane was 6.8 MPa, and the elongation at break reached the value of 139%. The hydrophobic property was obviously improved with the increase of chain extension reaction time. When the time was 120 min, the water contact angle was still as high as 112° after 240 s.

Key words: polyurethane, chain extension time, electrospinning, mechanical property, water resistance

摘要： 为了优化聚氨酯纳米纤维膜的力学性能和润湿性能,以聚四氢呋喃醚二醇(PTMG)、4,4′-亚甲基双(苯基异氰酸酯)(4,4′-MDI)和1,4-丁二醇(BDO)为主要原料合成聚氨酯(PU),并利用静电纺丝技术制备PU纳米纤维膜。研究了不同扩链段反应时间对合成聚氨酯物理性质和静电纺纳米纤维膜性能等的影响。采用红外光谱仪(FTIR)、高效液相色谱仪(GPC)、热重分析仪(TG)、扫描电子显微镜(SEM)、多功能拉伸仪和动态/静态接触角仪对PU结构和纤维膜的形貌性能进行表征。结果表明:当扩链反应时间由90 min增加至120 min时,聚氨酯分子量增加,合成聚氨酯的热稳定性略有提高,纳米纤维的成膜性能增强。当扩链反应时间为120 min时,纳米纤维膜的断裂应力为6.8 MPa,断裂伸长率达到139%;疏水性能随着扩链反应时间的增加明显提高,当扩链反应时间为120 min时,240 s后水接触角仍然高达112°。

关键词: 聚氨酯, 扩链时间, 静电纺丝, 力学性能, 耐水性