单宁交联聚氨酯水凝胶的制备与性能研究

Study on the Preparation and Properties of Polyurethane Hydrogel Crosslinked by Tannin

以单宁为交联剂通过两步法成功合成了不同交联度的聚氨酯干凝胶（TAPU）,并通过傅里叶红外光谱（FTIR）和综合热分析（TG-DSC）表征了该弹性体的结构和热性能。进一步制备了TAPU水凝胶,研究了该凝胶的溶胀性能、力学性能和水解性能。结果表明：由于单宁在TAPU中同时起到化学交联和物理交联的作用,单宁含量是凝胶力学性能和溶胀性能的重要影响因素。酚类与异氰酸酯反应的可逆性赋予了TAPU凝胶一定的水解性能,通过对TAPU水解前后红外光谱的分析证实了水解机理。同时研究了不同水解度下凝胶的溶胀性能和力学性能。

Dry hydrogels（TAPU） with different crosslinking degree were successfully synthesized through two-step method, of which tannin acted as crosslinking agent. The structure and thermal properties of the elastomers were characterized by Fourier transform infrared spectroscopy（FTIR） and comprehensive thermal analysis（TG-DSC）. Furthermore, the TAPU hydrogels were prepared and their swelling properties, mechanical properties and hydrolysis properties were studied. The results show that tannin content plays an important role in the mechanical properties and swelling properties of TAPU hydrogels as tannin create both chemical crosslinking and physical crosslinking. The reversibility of reaction between phenol and isocyanate gives these hydrogels hydrolysis ability. And the hydrolysis mechanism was confirmed by analysis on the IR spectrums TAPU before and after hydrolysis.