新型茶单宁聚氨酯材料的研究(Ⅰ)

以茶叶中浸提的茶单宁为原料 ,合成了生物降解型聚氨酯泡沫材料 ,并考察了它对NH4 Cl包覆的控制缓释性能。在模拟自然界雨淋的作用下 ,释放曲线大致呈抛物线型。对该材料的机械强度做了拉伸实验 ,表明茶单宁在聚氨酯网络中起交联作用 ,增加了其强度 ,该聚合物可用作包装材料。通过三方面的实验 (碱煮 ,微生物侵蚀及酶水解 )定性地说明了茶单宁聚氨酯比普通聚氨酯易于生物降解 ,并通过D .S .C谱图对其原因做了初步探讨。

Study on a Novel Biodegradable Polyurethane Material from Tea(Ⅰ)

A novel biodegradable polyurethane material was synthesized by the tannin of tea dissolved in glycol adipicate polyester reacting with diisocyanate. The controlled release properties of this material as a carrier for ammonium chliride were investigated. Tensile properties were measured showing this new polyurethane network was further crosslinked than the usual polyurethane without the tannin of tea. Their biodegradability was investigated by testing their resistance to alkali hydrolysis(10% w/v NaOH), to microbial/bacterial attack when buried in soil and to enzymatic hydrolysis. The biodegradation in 10% NaOH solution was followed by using differential scanning calorimetry (d.s.c).All of these characterizations indicated that this new polyurethane network degraded more quickly than the usual polyurethane without tannin of tea. Possible applications of this new material could be envisaged in the fields of agriculture, food packaging and medicine-carrier.