摘要： 通过蓖麻油与3-巯基丙酸间的巯基-烯点击反应合成了一种蓖麻油基多元羧酸(MCO),并将其作为亲水扩链剂与异佛尔酮二异氰酸酯(IPDI)和蓖麻油共聚制备了一系列羧基含量不同的蓖麻油基水性聚氨酯树脂(COPU)。用核磁氢谱(1H NMR)和核磁碳谱(^13C NMR)确认了蓖麻油基亲水扩链剂的结构;采用红外光谱(FT-IR)对MCO及COPU的结构进行分析;并采用摆杆硬度测试、吸水率测试、示差扫描量热仪(DSC)和热重分析仪(TGA)对聚氨酯涂膜的机械性能和物理性能进行表征。结果表明:随着亲水基团含量的增加,涂膜的硬度逐渐降低、吸水率逐渐增大,对玻璃化转变温度(T_g )及耐热性能影响不明显。水性聚氨酯涂膜浸泡192 h后不泛白,不开裂,吸水率仅为6.52%,有较好的耐水性。

关键词: 巯基-烯点击反应, 蓖麻油基多元羧酸, 亲水扩链剂, 耐水性, 水性聚氨酯

Abstract: A novel castor oil- based polybasic acid (MCO) was synthesized through thiolene coupling reaction between castor oil and 3-mercapto propionic acid, which was then used as a hydrophilic monomer reacting with isophorone diisocyanate (IPDI) and castor oil to prepare a series of bio-based waterborne polyurethane resin (COPU). The structure of castor oil-based chain extender was verified by ¹ H NMR and ^13C NMR. FT-IR was used to characterize the structure of Mco and COPU. Furthermore, pendulum hardness test, water absorption test, differential scanning calorimetry(DSC)and thermal gravimetric analysis(TGA) were used to characterize the mechanical properties and thermal properties of COPU -based films. The result showed that with increase of the content of hydrophilic group, the hardness of COPU films was gradually decreased, but the water absorption was increased gra duall and no obvious effect on the value of T_g and thermal resistance. There was no blushing and cracking defects on the COPU film after immersion in water for 192 h, and the water absorption was only 6.52%, indicating good resistance to water.

Key words: thiol-ene coupling reaction, castor oil-based polybasic acid, hydrophilic chain extender, water resistance, waterborne polyurethane