Synthesis And Applied Research Of Polyacrylamide-styrene Soap-free Emulsion

With the development of papermaking, polymer latex especially the soap-free latex has become indispensable in papermaking and paper machining, in order to increase the dry wet tensile strength, tear strength, folding strength and the hydrophilicity of paper, it was broadly used for pulp additive, paper impregnant and paper coating agent.In this research styrene and acrylamide were chosen to prepare soap-free latex, and the reaction character and their application in papermaking industy were studied. In chapter 2, we do research on the copolymerization kinetics, the results showed that the copolymerization rate equation could be Rp= kp[M]^0.53[I]^0.54 , the apparent activation energy was 91.89 kJ/mol and the chain-growth activation energy(Ep) was 21.79 kJ/mol; The presence of monomer methyl methacrylate (MMA) also can increase the reaction rate of Am/St, the reaction rate of second stage become quicker with increasing more quantity of MMA. In chapter 3, the influence of solid content, molar rate, initiator concentration, monomer MMA and solvent acetone on the particle diameter and stability were investigated, the experiment showed that we can control the particle diameter by changing these factors, the stability depend on the surface charge densities and the content of on-surface hydrophilic groups; based on Chi Wu's structural models for stabilization, we studied the influence of molar rate and the concentration of initiator on the particle diameter, and found these factors accord with the model. In chapter 4, we investigate the application of the latex, the series of latexes performed good paper dry strength ,BR-3 performed best among the emulsions as agent with molar rate: AM: St: MMA=7.5:1.5:1, and it is better than anion polyacrylamide , amphoteric polyacrylamide and cation starch.