Structure And Performance Analysis Of Soybean Based Environmental Friendly Adhesive For Wood

Wood based panel is a kind of wood that can be used for production and life by bonding the boards together with adhesives.Most of the adhesives used in wood-based panel are aldehydes.With the improvement of people’s awareness of environmental protection,aldehydes free adhesives have been developed.Soybean adhesive has the advantages of wide sources of materials,renewable,no pollution to the environment,but the performance of pure soybean adhesive can not meet the needs of industry,it needs to be modified before it can be used.At present,the modification of soybean protein is mainly toxic chemical reagent modification,and a small amount of chemical pollutants will be produced in the process of use.In order to meet the needs of industrial production and to produce environmentally friendly modified soy-based wood adhesives,soy protein is modified.This paper uses sodium lignosulfonate,sodium carboxymethyl cellulose and protease to modify the soybean protein,and conducts experimental research on the modified soybean protein.The study found:(1)The binding process of sodium lignosulfonate and soybean protein is an exothermic reaction,and the binding affinity of this reaction process is1/2.85E7;the binding process of carboxymethyl cellulose and soybean protein is an exothermic reaction,The binding affinity is 1/3.93E9;the protease has a strong binding strength with soy protein,and the binding process is an exothermic reaction.The binding affinity of this reaction is1/1.07E7;through analysis,the protease has the best denaturation effect on soy protein.It is known that after the use of protease to modify the soy protein,the protease can make the structure of the soy protein more stable.Therefore,this research mainly uses the protease to modify the protein and analyzes the performance and structure of the adhesive.(2)After the protease modification treatment,the remaining solid content of the adhesive is higher than that before the modification.It can be determined that after the protease modification,the small molecular structure inside the protein is connected into a macromolecular structure,making the protein structure more stable;(3)With the increase of the hot pressing temperature and the extension of the hot pressing time,the shear force of the plywood will increase,and it is finally determined that the hot pressing temperature during this experiment is120 ℃,and the hot pressing time is 30 min.The plywood has the best performance under pressure conditions;the shear force of the plywood prepared by the protease modified adhesive is much better than that before the modification,and the plywood prepared under the optimal hot pressing conditions meets the national standards;passed The water resistance of the plywood is treated,and it can be found that the water resistance of the plywood prepared by the adhesive modified by the protease is greatly improved,and it meets the national standard.(4)The internal structure of the protein adhesive before and after modification has changed,and the OH group and NH group of the modified adhesive are reduced,which is conducive to improving the water resistance of the adhesive;the protein adhesive before and after modification The secondary structure has also changed,and its α-helical content is increased,which is beneficial to improve the stability of the adhesive and increase the adhesive strength of the adhesive;by using different temperatures to treat the modified adhesive,it is found that,As the temperature increases,the OH group and NH group of the adhesive decrease,and the α-helical content increases,which is beneficial to improve the adhesive strength of the adhesive and improve the water resistance of the adhesive.After modification,the structure and performance of the protein adhesive are improved,and the prepared plywood meets national standards.