Study On The Preparation And Feature Of Multi-modified Starch Based Bio-adhesives

Since the starch source is abundant,it is a desirable material for preparing biomass adhesive.However the adhesive of ordinary starch or single modified starch has flaws like low solid and high viscosity,being easy for gelling and aging etc,as well as deficiencies in stability during storage,water resistance,bonding strength etc.This thesis employs the method of single factor orthogonal experiments to research the etherification-oxidation-grafting-crosslinking multi-modification technique for starch.as well as prepare multi-modified starches based bio-adhesives with good performance.In this paper,it firstly determines preparation process of hydroxypropyl starch,introduces hydroxypropyl based on starch molecules,which improves viscosity stability,shear resistance,freeze-thaw stability and storage stability of the starch;then by oxidation of compound modification,it reduces the viscosity of hydroxypropyl starch,improves the stability and cohesiveness of paste.Then it takes the etherification of oxidized starch as graft skeleton,butyl acrylate(BA)and vinyl acetate(VAc)as grafting monomer,potassium persulfate as initiator,to determine the optimal grafting conditions and waterborne polymer segments was successfully grafted in etherification oxidation starch chain,which improves biomass adhesive shear strength obviously.By introducing self-Crosslinked under ambient temperature of DAAM and ADH,the multi-modified starches adhesive compression shear strength,especially the wet strength have been significantly improved,therefore,it determines the preparation process for etherification-oxidation-grafting-crosslinking multi-modified starches based bio-adhesives.In this paper,multi-modified starches based bio-adhesives product prepared is characterized by high solid content,strong adhesion,good water resistance,storage stability,green environmental protection,which overcomes deficiencies and disadvantages existing in the original single modified starch or starch adhesive and their physicochemical properties are better than standard requirements for polyvinyl acetate emulsion adhesives for woods(white emulsion)(standard HG/T 2727-2010),the content of harmful substances is far lower than the national standard(GB 18583-2008),which can replace the traditional white emulsion for wood processing and interior decoration.