Study On The Synthesis And Application Of Starch-based Wood Adhesive

Starch is a high polymer which is composed of a great deal of glucose unit．Ithast much of hydroxy which combine with water to form strong hydrogen bond andmake it have too weak bonding strength and water-resistant to reach class adhesivelevel and satisfy the requirements of wood-based panel production．This thesis triedto improve bonding strength and water endurance performance to meet theapplication demand of class Ⅱ plywood，by a series of chemical modificationmeans which include adding cross linking agent and grafting alkene high polymerto reduce the number of hydroxyl and introduce other active bases．Crosslink and graft double-modification of oxidized maize starch, withimproved bonding strength and water-resistance, was prepared through two-stepchemical reactions. Firstly, epichlorohydrin was chosen as crosslink agent inthe chemical modification process. The orthogonal design program was used asmain experiment means． The optimum conditions were as follows:epichlorohydrin4.0wt%, pH=10, reaction time3h, reaction temperature50℃.Secondly, butyl acrylate was chosen as chemical modifying agents by graftmodification. The orthogonal design program was used as main experimentmeans．The optimum conditions were as follows: APS0.7wt%, butyl acrylate7.0wt%, reaction time3h, reaction temperature60℃, SDS1.0wt%. FTIR, SEM, TG,DSC and other testing methods were used to characterize the changes of themodified and unmodified starch, and starch modification mechanism was obtainedbased on these changes.Finally, Starch-based Wood Adhesive could be obtained by add stabilizingagent (PVA), drier agents (sodium bentonite), gelatinization agent (NaOH) inmodified starch. The effect of stabilizing agent, drier agents and gelatinization agent onstable storage stability of the product, mobility, speed of drying was studied.The properties of starch-based wood adhesive prepared at optimal conditionswe analyzed. Properties of starch-based wood adhesive were compared withindustry standard of urea-formaldehyde resin wood adhesives. For the adhesiveprepared under the best conditions, wood adhesives could be obtained with highbond strength(7.5Mpa), good water-resistance(48h), stable storage stability(200d), better viscocity(1250mPa·s), which could meet national standard GB/T9846-2004.Lower cost and no environment pollution make it abroad market prospects in thewood processing industry.