Preparation And Application Of Acrylonitrile Modified Starch Graft Copolymer

With the constantly development of printing technology and relationalpaper fields, traditional inner stuff sizing not only consumes a great quantity ofsizing agent, but also influences the paper physical property of paper, so we needhigher requirements about surface sizing of pulp craft. At present, polymer sizingagent at home does not give consideration to paper’s surface strength, foldingendurance and folding solvent in some fields, exploiting high-performancesurface sizing agent has become a hot spot research in papermaking.Firstly, the cassava starch （CS） is modified by acrylonitrile （AN） in orderto raise the membrane property of CS. Secondly, cross-linking withN-hydroxymethyl acrylamide （NHAM） to raise the water-solubility of CS andthe branch CS’ free radical grafting point. Later, the polymer latex is synthesizedthrough the way of direct dropwise, by using AN-CS as a dispersant,dimethylaminoethyl methacrylate （DM） as cationic monomer, styrene （St） ashard monomer, and butyl acrylate （BA） as soft monomer. At the same time,control experiment is preparated through by traditional way and using CS. Whenthe AN-CS surface sizing agent was being preparated, leading into introductionof zirconium oxychloride can enhance application result of the sizing paper. Theeffects of variety reaction condition on the latex stability and the sizing resultwere studied. The optimum synthesis conditions are as follows: about the systemof AN-CS polymer latex, the dosages are as follows: m（DM）=2%，m（AN-CS）=10%, m（AN-CS）:m（St+BA）=1:2, m（NHAM）=0.3%, m（H₂O₂）=2%,n（FeSO₄）:n（H₂O₂）=0.03, m（St）:m（BA）=3:1, the reaction temperature being80℃,the dropwise time being two hour, finally keep temperature reaction for four hour,pH being5～6, we can get stable polymer latex. When sizing with starch, thecorrugated paper’s ring crush strength index can reach12.67N·m/g，thedeflection can reach41g·cm, improving by92.39%and51.58%, the sizingdegree can reach136s. At the foundation, AN-CS surface sizing agentintroducing zirconium oxychloride, also improves the paper’s sizing degree can get147s.Contrasting the AN-CS surface sizing agent with the CS surface sizingagent, the result has been proved than the AN-CS surface sizing agent is betterthan CS surface sizing agent. At the same situation of raw material, the averagegrain size of AN-CS latex is less than that of CS latex’s. The application testdiscovers that Zr⁴⁺can combine with fibre quickly, in order to add the retentionrate of polymers on paper. Sizing Zr⁴⁺with Al³⁺can greatly improve the paper’ssurface property, because the Al³⁺can promote the adsorb capacity of Zr⁴⁺.