Metal Ion-Catalyzed Low-Temperature Curing of Urushiol-Based Polybenzoxazine
Wen Yang, Yaofeng Xie, Jipeng Chen, Chunmei Huang, Yanlian Xu, Yucai Lin
Abstract
In this work, urushiol-based polybenzoxazine is cured by the Lewis acid (FeCl 3 , AlCl 3, and CuCl 2 ) at low temperature instead of high thermal curing temperature. The effect of the Lewis acid on structures and properties of the polymers is revealed. The relating urushiol-based benzoxazine monomer (BZ) was synthesized by natural urushiol, formaldehyde, and n -octylamine. The monomer was reacted with the Lewis acid with a molar ratio of 6:1 (N monomer : N Metal ) at 80°C to obtain films that can be cured at room temperature. The chemical structures of benzoxazine monomers were identified by Fourier-transform infrared spectroscopy (FTIR) and 1 H nuclear magnetic resonance spectroscopy ( 1 H-NMR). The interaction between the metal ion and the polymers is revealed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance-FTIR (ATR-FTIR). The effect of the Lewis acid on the mechanical properties, wettability, and thermal stability was investigated. The results show that the benzoxazine cured by Cu 2+ has a better performance than that cured by Al 3+ and Fe 3+ .