玻璃纤维增强塑料用热解油-酚醛树脂的合成工艺

Synthesis process of bio-oil phenolic resin used for glass-fiber reinforced plastic

采用热解油、苯酚和多聚甲醛合成满足玻璃纤维增强塑料(玻璃钢)制备要求的热解油-酚醛树脂,通过单因素试验考察了合成工艺条件对树脂性能的影响规律,并利用正交试验优选出最佳合成工艺条件为:甲醛/苯酚摩尔比1.8、热解油添加量为苯酚质量的20%、NaOH/苯酚摩尔比0.25、反应时间10 min。在该条件下合成的热解油-酚醛树脂的主要性能为:黏度743 m Pa·s、固体含量77.1%、游离酚含量3.1%、游离醛含量1.2%、凝胶时间28.0 min、氧指数92.7%,能够较好地满足制备玻璃钢的需要。利用热解油-酚醛树脂制备的玻璃钢材料的主要性能为:氧指数90.3%、弯曲强度138.5 MPa、弯曲模量4 582.3 MPa,表明其具有良好的阻燃性能和力学强度,且以上性能均优于普通酚醛树脂所制玻璃钢;通过红外光谱和扫描电镜分析发现,热解油-酚醛树脂与普通酚醛树脂具有相似的分子结构和微观表面形貌。

In this study,bio-oil from fast pyrolysis of renewable biomass was used as the rawmaterial to synthesize bio-oil phenolic resin,which was a desirable resin for fabricating glass-fiber reinforced plastic. During the synthesis process,the paraformaldehyde was used to achieve the properties of high solid content and lowviscosity. The effects of process conditions were studied and the optimal technological parameters were obtained as follows： the molar ratio of paraformaldehyde to phenol was 1. 8,bio-oil content was 20% based on phenol mass,molar ratio of Na OH to phenol was 0. 25 and reaction time was 10 min. The properties of bio-oil phenolic resin were found that： viscosity was743 m Pa·s,solid content was 77. 1%,free phenol mass ratio was 3. 1%,free formaldehyde mass ratio was 1. 2%,curing time was 28. 0 min and oxygen index was 92. 7%,which could meet the preparation of glass-fiber reinforced plastic by hand lay-up molding process. The glass-fiber reinforced plastic was fabricated by bio-oil phenol with oxygen index of 90. 3%,bending strength of 138. 5 MPa,bending modulus of 4 582. 3 MPa,which had better performances than those made by ordinary phenolic resin. The tested results also indicated that adding bio-oil during the synthesis process could improve the fire resistance and brittleness of phenolic resin. The chemical structure and surface characteristics of bio-oil phenolic resin were analyzed by Fourier transform infrared spectra and scanning electron microscope（ SEM）,respectively. The results showed that the strength and position of strong absorption peaks in bio-oil phenolic resin were similar to those of phenolic resin,such as phenolic hydroxyl,hydroxyl methyl and benzene. Moreover,it could be concluded that adding bio-oil helped to form more chains of hydrocarbons during the synthesis process,which was beneficial to modify the brittleness. The SEMimages showed that the cured phenolic resin was featured by brittle failure because line shape cracks and solid particles were observed. The surface of cured bio-oil phenolic resinwas smooth and flat,and was consisted of corrugations,which indicated that the stronger intermolecular force was formed in the crosslinking structure of resin.