坚木单宁基泡沫材料的制备及其力学性能

Preparation and mechanical properties of biomass quebracho-tannin-based foams

为了开发酚醛泡沫保温材料的替代产品,以生物质坚木单宁为基体,以不同的发泡剂(正戊烷和乙醚)、交联剂(甲醛和乙二醛)及糠醇作为试验变量,成功制备出可在室温下自发泡固化的生物质单宁基泡沫材料。阐述和优化其制备工艺,分析不同试验条件对泡沫的密度控制、微观结构、保温阻燃性能以及力学性能的影响。结果表明:坚木单宁基泡沫材料的密度在70~330 kg·m^(-3)的范围内可控,相应的泡孔直径在96~3615μm之间,且泡孔直径随着密度的增大而减小,呈线性关系。坚木单宁基泡沫材料的密度随着发泡剂和糠醇添加量的增加而减小,但受交联剂的影响不大。在不同的发泡剂和交联剂添加量条件下,泡沫材料的压缩强度和密度呈正相关关系。糠醇添加量对力学性能的影响,除了表现在密度的改变导致力学性能的变化之外,也受到泡沫材料自身交联程度的影响。通过和传统的酚醛泡沫材料比较,单宁基泡沫材料具有优良的阻燃、保温隔热和力学性能,是一种极具潜力的新型、绿色的泡沫材料。

To develop a novel material that can be used as a substitute for phenol foam,tannins are used instead of the phenol components to prepare tannin-based foams at room temperature.The impact of the blowing agent content(n-pentane and diethyl ether),crosslinking agent(formaldehyde and glyoxal),and furfuryl alcohol on the density,microstructure,heat preservation,flame retardant property,and mechanical properties were examined and the processing conditions were optimized.The results show that the density of tannin-based foam was controllable in the range of 70-330 kg·m^(-3) by adjusting the experimental conditions.The pore sizes of these tannin-based foams were in the range of 96-3615μm.The pore size decreases with increased density and exhibits a linear relationship.In addition,the density of tannin-based foams decreased with an increase in foaming agent and furfuryl alcohol.The influence of different cross-linking agents,formaldehyde,and glyoxal,were not significant.Under different content of foaming and cross-linking agents,the compression strength and density of the solid tannin-based foam material were found to be positively correlated.The effect of furfuryl alcohol on mechanical properties is caused by the density and the cross-linking degree of the foam.Compared with traditional phenolic foam,the tannin-based foam has excellent flame resistance,thermal insulation,and mechanical properties.Tannin-based foam is a new and green foam material with high application potential.