Reactive Diluent Derived from Ferulic Acid for the Preparation of a Fully Biobased Unsaturated Polyester Resin
Zenghui Dai, Qing Li, Zhiwei Chen, Rashidul Kabir Shawon, Yiyuan Zhu, HongFen Lv, Feiya Fu, Yaofeng Zhu, Yaqin Fu, Xiangdong Liu
Abstract
A reactive diluent for the preparation of a fully biobased unsaturated polyester resin (UPR) was developed and is presented here. The diluent, 4-vinylguaiacol acetyl ester (AC4VG), was obtained via a simple two-step synthesis: decarboxylation from ferulic acid (FA) and acetylation of the decarboxylated product, 4-vinylguaiacol (4VG). This diluent shows excellent miscibility with biobased unsaturated polyester prepolymer (UPP) that had been synthesized from succinic acid (SA), 1,3-dihydroxypropane (PD), and itaconic acid (IA). A mixed solution of these possessed a very low viscosity at 174 mPa·s at room temperature when 40 wt% AC4VG was added. Moreover, its vinyl group brought high reactivity for free radical copolymerization with the UPP, and the benzene ring structure enabled a high glass transition temperature (Tg) of the cured UPR. When the fully biobased UPR was reinforced by cotton fabric, a strong tensile strength at the break of approximately 65.8 MPa, a Tg of 135 °C, and a Td5% of 276 °C were achieved. This work suggests that the fully biobased UPR reported here is a promising candidate for replacing petroleum-based ones, and the diluent AC4VG played an important role in the performance of this biobased UPR.