| In order to solve the problems of toxic and harmful petroleum-based adhesives and the increasing shortage of raw materials,this paper uses green biomass raw materials such as corn starch,lignin,silicone,itaconic acid,and uses no or less organic solvents in the synthesis process two different biodegradable and non-volatile poison-based bio-based adhesives were prepared,namely lignin-modified corn starch bio-adhesive and itaconic acid-silicone modified corn oxidized starch adhesive.Firstly,starch and lignin are used as raw materials,and water is used as a solvent to prepare lignin-modified corn starch to prepare a biological adhesive?St-SLS?.The experiment discussed the influence of different factors and conditions on the viscosity and dry bonding strength of the adhesive,and the best preparation process conditions were as follows:m?H2O?/m?St?was 15:1,m?SLS?/m?St?is 0.15:1,m?APS?/m?St?is 0.02:1,reaction temperature is 80?,reaction time is 6h,p H=3?5,under the above conditions,St-SLS adhesive The viscosity is 1434m Pa·s,and the dry bonding strength can reach 3.229MPa.In addition,the experiment used a variety of testing and characterization methods to study the reaction mechanism of starch and lignin under the action of initiators.FT-IR and UV-VIS spectrum analysis proved that starch was successfully grafted with lignin.TG analysis showed that the graft copolymerization of lignin was conducive to improving the thermal stability of the adhesive.XRD analysis proved that the starch gelatinization process The rupture of the crystal structure is conducive to the progress of the graft copolymerization of lignin.The rheological properties analysis proves that the graft copolymerization of lignin is beneficial to enhance the energy storage and loss modulus of the St-SLS polymer.Based on the better dry adhesive strength and solubility in hot water of the bio-adhesive?St-SLS?prepared by lignin modified corn starch,the application of this method in paperboard bonding was investigated experimentally.The experimental results showed that St-SLS Used in the field of cardboard packaging,it can solve the problem of"stickies"in the process of waste paper pulping,and is conducive to the secondary recycling of fibers.Lignin-modified corn starch adhesive?St-SLS?has good dry bonding strength,but due to the strong hydrophilicity of sodium lignosulfonate?SLS?,its wet bonding strength is poor.However,water resistance is a very important indicator of adhesives.Therefore,in order to improve the water resistance of starch-based adhesives,the experiment used biomass monomer itaconic acid and two silicone monomers to modify corn starch.A starch-based polymer system with Si-O-Si as the core of the hydrophobic network and itaconic acid as the bridge was constructed to prepare itaconic acid-silicone modified corn starch adhesive?IA-M/B-OSt?.The experiment discussed the influence of different factors and conditions on the viscosity and wet bonding strength of the adhesive,and obtained the best preparation process conditions as follows:reaction temperature 70?,reaction time 17h,the amount of initiator is the quality of itaconic acid monomer 7.5%,Emulsifier dosage:m?SDS?/m(?IA-? content.The viscosity of IA-M/B-OSt prepared under the above conditions is 11060m Pa·s,and the wet bonding strength is about 1.2MPa,which exceeds the 0.7MPa of national standard GB/T 17657-2013.In addition,the experiment used a variety of characterization methods to study the graft copolymerization reaction mechanism of itaconic acid,silicone and starch under the action of initiator.FT-IR?1H NMR and scanning electron microscopy spectroscopy showed that itaconic acid and organosilicon monomers were successfully grafted onto starch molecules.TG-DSC analysis showed that the best hot-pressing of the adhesive temperature range.The experiment also discussed the effect of hot pressing conditions on the wet bonding strength of the prepared IA-M/B-OSt adhesive.The experimental results showed that the conditions of hot pressing temperature of 175?,hot pressing time of 40min,and hot pressing pressure of 1.6MPa Next,the wet bonding strength of IA-M/B-OSt adhesive can be increased to about 1.3MPa.XRD,XPS and 29Si NMR all proved the formation of crystalline structure and the construction of Si-O-Si structure during hot pressing,indicating that suitable hot pressing conditions can improve the hydrophobic capacity and wet bonding strength of the adhesive.The significance of this research work is that the preparation of modified starch-based bio-adhesives with good adhesion and water resistance provides theoretical,technical support and experience for the study of high value-added starch products,and has a wide range of applications Value;Explore the crosslinking copolymerization mechanism of lignin and starch,the crosslinking copolymerization mechanism of silicone and itaconic acid and starch,and provide a new scientific method for the development and preparation of starch-based adhesives. |
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