水量对水性聚氨酯聚集形态及粘接性能的影响

Effect of Water Content on the Aggregation and Adhesion Properties of Waterborne Polyurethane

以聚己二酸1,4-丁二醇酯二醇(PBA)为软段,以异氟尔酮二异氰酸酯(IPDI)、2,2-二羟甲基丙酸(DMPA)、一缩二乙二醇(DEG)、水为硬段合成了一系列水性聚氨酯(WPUs),探讨了水加入量对WPUs性能的影响。通过傅里叶变换红外光谱测试(FT-IR)、粒径测试、凝胶渗透色谱测试(GPC)、差示扫描量热测试(DSC)、X-射线衍射测试(XRD)、热重测试(TGA)、力学性能测试等对其结构和性能进行表征。通过红外曲线拟合结果、DSC和XRD测试结果证实,随着加入体系中水量的增加,氢键化N-H伸缩振动峰强度增加,WPUs结晶度降低。随着水量的增加,乳液平均粒径增大且分布变宽,同时WPUs的分子量及分子量分布系数逐渐增加;胶膜的拉伸强度和断裂伸长率均呈现先增大后减小的趋势,T型剥离强度显示同样的趋势。力学性能测试结果表明,当水加入量为0.94%(wt)时,胶膜的力学性能最佳,拉伸强度达36.7 MPa,断裂伸长率达1026.5%;当水加入量为0.74%(wt)时,水性聚氨酯的T型剥离强度达到最大值,为1.9 N×cm^(-1)。

Waterborne polyurethane（WPUs） was prepared with poly（1,4-butanediol adipate）diol（PBA） as soft segments, and isophorone diisocyanate（IPDI）, 2,2-dimethylol propionic acid（DMPA）, diethylene glycol（DEG） and water as hard segments. Effects of water contents on WPUs performance were investigated. The structure and properties of WPUs were characterized by Fourier transform infrared spectroscopy（FT-IR）, particle size analysis, gel permeation chromatography（GPC）, differential scanning calorimetry（DSC）, X-ray diffraction（XRD）, thermal gravimetric analysis（TGA） and tensile tests. The results show that when water content increases, the intensity of hydrogen bonded N-H stretching vibration peaks increases and the crystallinity of WPUs decreases. Moreover, the average particle size and particle size distribution of emulsion increase, and the molecular weight and polydispersity of WPUs also increase. Meanwhile, the tensile strength, elongation at break and T-peel strength of the films increase first and then decrease. The results indicate that the tensile strength of the film reaches to a maximum value of 36.7 MPa and the maximum elongation at break is 1026.5% when the water content is 0.94%（wt）. The T-peel strength of the waterborne polyurethane reaches to a maximum value of 1.9 N×cm^-1 when the water content is 0.74%（wt）.