温敏聚氨酯膜制备及性能研究

Preparation and properties of temperature sensitive polyurethane membrane

以聚己内酯(PCL)、聚乙二醇(PEG)、4,4’-二苯基甲烷二异氰酸酯(MDI)等为主要原料,通过两步溶液嵌段共聚技术和干法转相技术制备了3种温敏聚氨酯(TSPU)膜TSPU(a)、TSPU(b)和TSPU(c)。采用傅里叶红外光谱法(FT-IR)、差示扫描量热法(DSC)、X射线衍射法(XRD)、扫描电镜法(SEM)等测试方法对TSPU膜的结构和性能进行表征并与普通聚氨酯(PU)膜进行比较。研究结果表明,PU膜无开关温度,TSPU(a)、TSPU(b)膜开关温度分别为54.8和31.17℃,TSPU(c)膜具有两个独立的开关温度,分别为35.3和57.0℃;TSPU膜表面光滑致密,截面为非对称的多孔结构;在开关温度前后,TSPU膜的透湿性和孔隙率发生了显著变化。当温度从25℃升高到35℃时,TSPU(c)的水蒸气透过量从70.49g/m^2·24h上升到145.71g/m^2·24h,增幅为106.71%;当温度从55℃升高至65℃时,其水蒸气透过量从306.32g/m^2·24h上升到578.54g/m^2·24h,增幅为88.87%。表明了研究中的TSPU具有温度响应特性。

Three kinds of temperature sensitive polyurethane (TSPU) membranes,TSPU(a),TSPU(b) and TSPU(c),were prepared by a two-step solution block copolymerization technique and a dry phase inversion technique,with PCL,PEG,MDI as the main raw materials.The structure and properties of TSPU membranes were characterized by FTIR,DSC,XRD and SEM,and compared with PU.The results showed that PU had no switching temperature,but TSPU(a) and TSPU(b) both had one switching temperature,54.8 and 31.17℃,respectively,while TSPU(c) membrane had two independent switching temperatures,35.3 and 57.0℃,respectively.The surface of the TSPU was dense,and the cross section was asymmetric porous structure.The moisture permeability and porosity of the TSPU membrane changed significantly before and after the switching temperature.As for TSPU(c),when the temperature raised from^25 to 35℃,the WVT increased from 70.49 g/m^2·24 h to 145.71 g/m^2·24 h,and the increase was 106.71%.When the temperature raised from 55 to 65℃,the WVT increased from 306.32 to 578.54 g/m^2·24 h,and the increase was 88.87%.It showed that the TSPU membranes had the characteristic of temperature-sensitive response.