The Synthesis Of Polymeric Emulsifier And Its Emulsification Mechanism

In today’s world, papermaking sizing has been transformed from acidic to alkaline. Because of its excellent performance and high reaction activity, Alkyl Ketene Dimer (AKD) as alkaline sizing agents was widely used in the paper industry, to increase the paper hydrophobicity and improve its printability. Generally, Traditional AKD emulsion is used cationie starch as emulsifier; there were some shortcomings in AKD emulsified with cationic starch, such as lower charge density and lower bond strength with AKD particles, lower efficiency and curing speed. It was well known that efficiency of the AKD sizing would finish in a week. So new AKD emulsifier was studied, it would be valuable to improve sizing efficiency and sizing curing speed in sizing theory and its application.Firstly, polydiallyldimethylammonium chloride (PDMDAAC) with high molecular weight was synthesized by the method of gradually increasing temperature. The effects of reaction temperature, reaction time, monomer concentration, the dosage of initiator and pH value on intrinsic viscosity were studied. The results were shown as follows:The initial concentration of monomer was60%. The dosage of the potassium persulfate (KPS) was0.2%compared to monomer amount. The pH value of the reaction system was5. The dosage of the Na4EDTA is0.003%of monomer amount. This thesis can got the results in the technological conditions as follows:The better value of intrinsic viscosity of PDMDAAC was1.64dl/g.The product was characterized by FT-IR.Secondly, the AKD wax was emulsified by used laboratory-made polyamine, The effects of different recttion temperature, recttion time, rotate speed and the dosage of aluminum sulfate, The results shown that the recttion temperature is80℃, the recttion time is9min, the rotate speed is10000r/min. And the false sizing phenomenon won’t appear. Finally, with HLB value theory and organic concept map theory as the guidance, AKD was emulsified by using laboratory-made polyamine and other commonly emulsifiers compounded as an emulsifying, The effects of different complex distribution ratio on the properties of emulsion were studied, The results shown that when the polyamines and cationic starch etherification agent complex ratio is1:1, Better dispersion and stability of the emulsion, The Cobb value of paper is24.11g/m2, Greatly reduce the requirements of the emulsification process temperature, speed and time. And the false sizing phenomenon won’t appear.