Research On The Non-formaldehyde Adhesive Produced By Laccase Activation Of Cellulosic Ethanol Lignin

Lignin as nature’s second largest biomass resources, is a major ingredient of plant skeleton,and plays the role of adhesive in plant body. With the use of cellulose in biological energy industry, lignin as a main ingredient residue, has not been effective utilization, and has long been burned directly and caused serious pollution to the environment. Using laccase activation technology to process the cellulose ethanol lignin to prepare the biomass based wood adhesives,not only use the lignin effectively, but also reduce the pollution for the environment, also fundamentally eliminate the use of formaldehyde and other toxic chemical raw materials,realizing the coordinated development of biological ethanol and plywood industry.(1) In this paper, firstly, the ethanol refining residue was separated and purified, the fourier infrared spectrum(FT IR), differential scanning calorimetry(DSC), nuclear magnetic resonance(NMR) were used to study the chemical composition and the structure of lignin. The study found that compared to the industrial alkali lignin, cellulose ethanol lignin retained more phenolic hydroxyl and alcoholic hydroxyl active functional groups, and the molecular structure preserved more completely, which made it a kind of important and promising prospect of biomass resource.(2) The best process for preparation of wood adhesives by laccase activation cellulose ethanol lignin was that, the dosage of laccase was 25% of the lignin, the reaction system of acetic acid/sodium acetate buffer solution pH value was 4.0, the reaction temperature was50 ℃, and the reaction time was 4 h. The amount of laccase and sodium acetate acetic acid in the reaction system pH’s influence on the bond strength were significant, and Tween-80 and PMDI could partly improve the wet strength of the plywood. The preparation of three layer poplar plywood used the cellulose ethanol lignin could met the requirements of the GB/T9846-2004.(3) Lignin was treated separately by the laccase and laccase mediator system(LMS), and the reaction mechanism between cellulose ethanol lignin with laccase and LMS was studied.The study found that laccase activation of the preparation of lignin adhesive might agglutinatein chemical way, and the mediator system could promote the reaction, which achieved better agglutination.