Preparation And Properties Of The Lignin/Epoxy Resin Composites

In this article, the blends were synthesized from the lignin blending with epoxy resin and the curing characteristics studied by DSC and FTIR methods. The results suggested that the reaction order of the compounds is0.93scale, the apparent activation energy Ea is74.58kJ/mol, pre-exponential factor A is5.84×107/s, the kinetic equation is da/dt=Aexp(-74.58/RT)(1-a)0.9310. The tests of FTIR analysis also revealed that the epoxy resin could be cured by corn stalk enzymatic hydrolysis lignin, there may be a bond connection formed between active groups in the lignin with epoxy and hydroxyl groups of epoxy resin molecular structure during the curing process. The exothermic peak and the molding difficulty of the blends would be reduced after the introduction of polyamide cure agent.As a base material the lignin was blended and thermoformed with epoxy resin, polyamide and fillers. And the effect of the ratio of raw materials, the molding conditions and the filler on the microstructure and macro-properties of lignin/epoxy resin composites was also discussed.The performance of the composites was different because of different ratio of raw materials. The results showed that comprehensive performance of the composite material is preferably at the amount of lignin of60%-65%and the polyamide content of20-24%in quantity of the composites. It illustrated the lignin could be distributed in the epoxy resin matrix uniformly, and there were no obvious interphase existed, which explained the good interfacial combination between lignin and epoxy resin. It would also be a possibility for the composite having better mechanical properties.There were differences of the comprehensive performance of the composites with diverse ratio of raw materials under different molding temperatures and pressures. Considering the influence of energy consumption, the molding temperature at130℃and molding pressure at lOMPa were more suitable for the preparation of lignin-epoxy composites.Modifier or filler may be added to the composites which was used to improve the performance of the composites to satisfy the requirements of different environments. The performance of the composites exhibited different changes after introduction of wood flour, polysulfide rubber or other reinforcing particles modified in the blend system. The increasing amount of wood flour will help to improve the mechanical properties of the composite material and reduce the density; addition of polysulfide rubber is suitable for10%. In addition, rigid filler will improve the bending resistance of the composite, and reduce the impact resistance performance a certain extent, but flexible filler have the opposite effect.