Synthesis Of Carboxyl Methyl Amphoteric Starch By One Step And Application In Papermaking

Systematic study on the preparation process,properties and application.Thereafter constructive viewpoints and new methods are put forward.The summarizing of research is as follows:The low degree of substitution carboxyl methyl amphoteric starch is synthesized by wet reaction process with cassava starch,3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTMA)and Sodium chloroacetate as material,ethanol aqueous solution as medium,and NaOH as catalyst.By single factor experiment,experiments study on the effect on the dosage of NaOH,CHPTMA and Sodium chloroacetate,temperature of NaOH process,time of NaOH process,temperature and time to reaction.By orthogonal design,the experiments select the main factors which are dosage of NaOH,dosage of CHPTMA and Sodium chloroacetate,reaction temperature and reaction time to prepare sample with the plan of L₉(3⁴).The optimum conditions are followings:The mole ratio of sodium hydroxide to Sodium chloroacetate and CHPTMA is 2.3,temperature is 40℃,time is 5 hours,the dosage of Sodium chloroacetate is 2.5%,and the dosage of CHPTMA is 5.5%.The sample's cationic degree of substitution is 0.032,anionic degree of substitution is 0.012,which is as strength agent suitably in papermaking experiment.In the experiment of papermaking,in part the degree of substitute of anion,cation is studied on the effect of paper physical properties,Simultaneously the optimal technology is found.Finally,the sample which is synthesized with the optimum technology is used in the experiment of papermaking.The results of papermaking application is analysised in two kinds of pulp including bagasse pulp and deink pulp.And,by analysis of paper structure,the experiments study on reaction mechanism of amphoretic starch.Finally,the samples of amphoretic starch get distinct effect than cationic starch in different pulp,especially in neutral papermaking condition.At the same time,experimemts find that amphoteric starch is more fit to strength agent for straw pulp.