Water resistance modification and characterization of starch based wood adhesive

The esterified starch adhesive was prepared treated by esterification processing with tartaric acid on corn starch,and then the isocyanate was used to modifiy the starch adhesive.The influences of reaction temperature and PVA content on starch adhesive synthesis process were studied,as well as the effects of the solid content and isocyanates on the bonding strength and water resistance of starch adhesive were discussed.The results show that when the reaction temperature 50 ~ 55 ℃,PVA(10%) amount to be 15%,the adhesive properties was the best;the starch adhesive bonding strength and water resistance were improved significantly when the solid content to be 50%,adding a small amount of isocyanate,the treatment increased obviously bonding strength and water resistance,the products could meet the requirement of poplar wood GB/T9846-2004 II plywood.By adopting differential scanning calorimetry(DSC) and thermo gravimetric analysis(TGA),the esterified starch adhesive with isocyanate were characterized.The findings show that isocyanates could accelerate the curing rate and improve the thermal stability of starch adhesive.