Synthesis Of Adhesives From The Cassava Starch And Macromolecular Compounds

The high performance oxidized starch acetate was synthesized by using cassava starchthat abounds in South China as raw material, FeSO4 as catalyst, H2O2 as oxidation agent andethylene ester of acetic acid as the acetylating agent independently. Orthogonal design showedthe optimum conditions: oxidation was 0.1% catalyst, 6.0% H2O2, pH=10 ang the temperateof 50℃; acetylation was the time of 1.5 h, 5.0% ethylene ester of acetic acid, the temperate of35℃and pH=9. The retro gradation of modified cassava starch and different degree ofsubstitution (DS) of oxidized starch acetate were investigated. The results showed that theretro gradation was reduced from 60% to 42% after modification, and reduced from 50 to 40with the increase of DS. The effect of different additives on adhesive dry speed wasdiscussed.Since the traditional adhesive has low cost but poor performance and the casein adhesiveperforms well but costs much, this article is also dedicated to develop an alternative labelingadhesive applicable to high-speed labeling machine, which performs as the level of caseinadhesive and costs nearly equal to traditional adhesive. By adopting new techniques, thetargeted labeling adhesive, namely, the hybrid starch adhesive is made through applyingseveral modification methods including etherification, cross linking, graft copolymerizationand blending to the above-mentioned modified oxidized starch that using cassava starch asraw material, thus water resistance of which is improved.Applying H3PO4 as catalyst, added formaldehyde and urea as reactants to the oxidizedcassava starch, the labeling adhesive's low water resistance can be improved by cross linkingand combination respectively with Styrene-acrylic emulsion, UF resin,M-UF resin andmixture of these two polymer materials. Its dropout time could be improved to 6 hours, 24hours, 48 hours and 72 hours after each combination from the initial 2 hours, which wouldmatch the modern technical requirement of labeling adhesive. Besides, the group changing ofreplacement has been analyzed in this article by Fourier transform infrared spectroscopy(FT-IR).