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In this paper,via molecular and particle design,the epoxy core-shell emulsion was developed as wet-strength additive,which meaned to meet some special paper’s need for high resistance to water and high wet strength.First of all,the three-step emulsion polymerization was employed to synthesize the anionic polystyrene-butylacrylate-glycidyl methaceylate(APSBG) core-shell emulsion.The effect of the process conditions and formulation on polymerization rate,monomer conversion ratio, polymerization stability,storage stability and epoxy value was investigated.Secondly,the two-step synthesis process of cationic polystyrene-butylacrylate-glycidyl methaceylate(CPSBG) core-shell emulsion was studied.Finally,PSBG was applied as paper wet-strength additive,and the effect of PSBG on paper dry-and wet-strength improvement and water absorption(Cobb Test) was studied. Factors such as PSBG retention,PSBG structure,curing temprature,and curing time,pH value of papermaking and filling were investigated.In addition,PSBG and papersheets were characterized by FTIR and SEM.Results showed that the high solid low viscosity APSBG and CPSBG could be effecitively synthesis,with monomer conversion more then 98%and epoxy value retaining more then 95%.The efficiency of CPSBG on paper was mainly studied because internal adding of APSBG alone was useless.Results showed that the efficiency of CPSBG was determined by the proportion and distribution of glycidyl methaceylate(GMA) in the CPSBG latex particles,the curing temperature determined the extent of the reaction of CPSBG and fiber,and papermaking conditions such as pH value,filling influenced the paper performance greatly.In neutral condition,CPSBG alone was applied. Results showed that up to 40%wet strength was obtained,folding endurance increased 10 times,and dry tensile strength(increased 35%),bursting strength(increased 72%),and sizing degree(Cobb water absorption decreased to 45g/m~2) increased greatly.
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