| Paper industry is one of the basic industries which is closely related to the development of national economy and social undertakings. But a lot of fiber residues were produced form papermaking and wastewater treament process. Currently the main treament for paper sediment were simple stacking, landfill and incineration. This processing method not only cost money, take up land, but also causes secondary pollution to soil, groundwater and air. The resource will be reused and the pollution will be eliminated if the sediment could be recycled in papermaking process as raw material. Both physical and chemical characteristics of waste paper psediment were studied in this paper. Novel amphoteric nano-polyacrylamide papermaking additive was synthesized. The optimal process conditions for additive was researched and the strengthening, retention and drainage mechanism of the amphoteric nano-polyacrylamide was studied to form the new technology to reuse paper sediment effectively.Both the OCC(corrugated cardboard) waste paper pulp and the sediment which came from OCC waste paper making process were studied. The number-average length of fiber in waste paper sediment were 0.39mm and the content of fines less than 0.2mm accounted for 52.48%. It was shown that the content of fines in sediment was much higher than waste paper pulp by pretreatment.The carboxyl content of sediment was 6.495mmol/100g. The anion demand of sediment was 13.354×10-3meq/g and cationic demand was 90.278×10-3meq/g. All of them are higher than the waste paper pulp fibers'. The zeta potential of sediment was -77.4mv which was lower than the waste paper pulp's. The pentosan content of sediment fiber accounted for 83.63 percent of waste paper pulp's and the ash content of sediment fiber was 2.20 times for waste paper pulp's.Taking DMDAAC, AM and MA as the monomers, butyl alcohol as the cosurfactant, liquid paraffin, isooctane, Cyclohexane as the oil phase based on the emulsifying system comprised of nonionic surfactants Span80,Tween60 and TritonX-10. The favorable system is ooctane/ Span80-Tween60 was selected as oil phase and eumulsifiers according to the study on the solubility of water phase in oil phase. Effects of monomer concentration, the mole content of AM, the mole ratio of DMDAAC and MA, the dosage of emulsifier, the quality ratio of composite emulsifier and cosurfactant as well as electrolyte anhydrous sodium acetate concentration on the minimum weight percentage content of emulsifiers and the most water solubilizing capacity of inverse microemulsion were studied by method of conductometry and dye. The experimental results show that stable inverse microemulsion system can be formed when monomer concentration, mole ratio n(AM)/n(MA)/n(DMDAAC), HLB, emulsifiers addition level, quality ratio of composite emulsifier and cosurfactant and NaAc concentration were 40%, 6∶2∶2, 11.30, 25%, 1∶7 and less than 2% respectively.The inverse microemulsion polymerization of amphoteric polyacrylamide by means of orthogonal experimental design was studied and the optimum conditions of orthogonal experiment had been got. The results showed that under the optimum conditions of reaction temperature 50℃, reaction time 3h, the volume of oil-water ratio 0.8:1, the concentration of initiator 1%, initiator ratio 1∶1.5, pH 4, molecular weight of 25.82×104 of 97nm particles was synthesized and the structure of the amphoteric polyacrylamide was identified by FTIR spectroscopy.The amphoteric nano-polyacrylamide was added in the mixed slurry as a paper additive when the sediment which came from OCC waste paper making process was reused with the ratio of 20%. The application condition was optimized and the best retention, filtration and enhancement effects were got. It was shown that the additive had good influence on paper properties and its quantitative, bursting index, tensile index, central pressure index and filler retention increased by 16.31%, 17.95%, 10.95%, 22.89% and 8.02% respectively by adding 0.8% AmPAM. By measuring the tensile strength of zero distance and other physical properties of the paper and using IR, SEM methods, the strengthening, retention and drainage mechanism of the amphoteric nano-polyacrylamide was studied. As for strength improvement, amphoteric nano-polyacrylamide had little effects on fiber strength, but it can increase the bonding area and bonding strength.
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