水性聚氨酯/明胶共聚物的制备及表征

Preparation and Characterization of Water-based Polyurethane /Gelatin Copolymers

摘要:

以二羟甲基丙酸（DMPA）作为亲水单体，采用甲苯二异氰酸酯（TDI），聚酯二元醇（PCDL）为原料，于偶联剂水杨醛的作用下在水性介质中制备了聚氨酯/明胶共聚物，用傅里叶红外光谱（FTIR）分析及凝胶渗透色谱分析（GPC）证实了该共聚反应的发生；研究结果表明：DMPA用量为5%时可得到稳定的聚氨酯乳液，此时胶膜的吸水率为8.52%；热重分析（TGA）显示共聚物胶膜在240 ℃开始分解；示差扫描量热分析（DSC）显示经改性后共聚物的玻璃化温度（Tg）为66 ℃；X-射线衍射分析 （XRD）表明聚氨酯的加入使得共聚物胶膜的结晶度大大降低，在聚氨酯用量为50%时共聚物的结晶度降为2%；力学性能分析及耐水性测试表明当聚氨酯含量从0%到50%变化时，胶膜的抗张强度由83 MPa下降到37.3 MPa，断裂伸长率从25.5%增大到325.6%，当聚氨酯含量从10%到50%变化时，胶膜的吸水率从251%下降到65%，可见聚氨酯的加入赋予了改性膜良好的综合性能。

Abstract:

The present work presents a study on the grafting of polyurethane onto chitosan in aqueous media. The effects of the amount of hydrophilic monomer on the water resistance of polyurethane were observed. Characterization of graft copolymers was performed by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction analysis (XRD), mechanical properties testing, and water resistance testing. TGA tests revealed that the thermal decomposition temperature of the copolymers increased significantly, being 34 ºC higher than that of pure gelatin while DSC measurements indicated that the glass transition temperature decreased by the introduction of polyurethane. Accordingly, the mechanical and anti-water absorption properties also proved to be enhanced greatly as evidenced by mechanical test and water absorptions data in which the copolymers containing 50% of polyurethane have highest elongation at break (325.6%), and lowest water absorption capacity (65%).