Preparation Of A Novel Amphoteric Polyacrylamide And The Study Of Its Applicationas Dry Strengthen Agent Of Waste Paper Pulp

Using waste paper pulp in the process of production instead of the virgin fiberwill lead to less consumption of wood or other papermaking materials, thus theresource utilization of the pollutants in the papermaking wastewater will be achieved.However, as a result of repeatedly washing and stirring, the content of fine fibers willrise; allow these fine fibers into the process of production will lead to low retentionrate and poor paper strength; what’s more, the anionic trash in the residue willinterference the wet end of the papermaking process. To deal with these problems, anovel papermaking agent should be developed, thus the fine fibers’ retention andstrengthen can be realized, and it will be easier for us to recycle fine fibers.The old corrugated container（OCC） waste paper pulp and the OCC wasteresidue were studied in this research on the surface charge characteristics and fibermorphology. The results indicate that the fiber in waste residue was shorter and thecontent of fines in residue was much higher. The electrical conductivity, the absolutevalue of Zeta potential and cationic demand of waste residue was higher. The data areas follow: The number-average length of fiber in waste residue is0.14mm; the contentof fines less than0.2mm accounts for75.93%and the content of fines less than100mesh are41.31%. The anion demand of residue is2.134μmoL/g and cationic demandis11.370μmoL/g, while the waste paper pulp fibers’ numbers are lower in a quietobvious way. The CTR value of both the OCC waste residue and waste paper pulp arelower than1, what’s more, the value of the waste residue is smaller. Thus the wasteresidue fiber possesses a higher negative charge. The Zeta potential of sediment is-65.13mv which is lower than the waste paper pulp’s. And the ash content and beatingdegree of residue fiber are higher.When it comes to the synthesis, with AM, DMC and AMPS as emulsificationmonomers，OP-10，Span80，Span20，Tween80and Tween60as emulsifiers，n-butylalcohol as auxiliary emulsifier，cyclohexane as organic solvents，the solubilizationcapacity of aqueous phase and conductivity of the system were studied. The results showed that when cycle-hexane is the most effective oil phase and Span80/Tween80is the best emulsifying system, the system turn to be clear and stable. The optimaleffect can be achieved when total mass concentration of monomer is40%，molar ratioof AM:DMC:AMPS is7:1.5:1.5, the HLB value is6，mass fraction of compositeemulsifier is12%and mass ratio of auxiliary emulsifier to composite emulsifier is1:6.The emulsifier takes up only10%of the oil phase in the inverse micro-emulsionsynthesized.After that, Span80/Tween60system is chosen to be the complex emulsifier andthe K2S2O8-NaHSO3to be the initializer, the conditions of amphoteric polyacrylamidepreparation by means of orthogonal experimental design were optimized under theformer situation. The results reflect the optimal condition for a successful synthesisare as follow: the reaction temperature is50℃, the reaction time is2.5h, the volumeof oil-water ratio is0.8:1, the initiator ratio is1∶1.5,and the pH is4. The novel agentsynthesized under the optimal situation has a83.31nm particles with the molecularweight of51×104, the solubility of it is quite well and is qualified as a papermakingagent, especially strengthen agent. The representation result of FT-IR shows that thecharacteristic absorption peaks of the three monomers appear in the figure, and theratio is the same as predicted, which is a proof of a successful synthesis.The ratio of OCC waste paper pulp and the OCC waste residue is7:3, add thenovel agent into the pulp, after multi-tests in a very long term, the best retention,drainage and strengthen effect can be achieved under the condition of adding0.3%AmPAM, it can be seen from the data that the quantitative, bursting index, tensileindex and filler retention of the paper with novel agent in it increased by15.1%,17.2%,7.7%, and7.89%respectively. What’s more, with the same dosage of adding,the novel agent AmPAM has a better effect and is more stable than the average agentswhich need dissolve before use. Last but not the least, the novel AmPAM is anenvironment-friendly agent.At the end of this research, zero span tensile strength and light-scatteringcoefficient of paper was tested and infrared spectra analysis, differential scanningcalorimetry (DSC) and scanning electron microscope (SEM) was also adopted to act as methods supporting the preliminary discussion of its reinforcing mechanism. It canbe speculated that the reinforcing mechanism of the amphoteric agent as follows:amino group in amphoteric polyacrylamide together with hydroxyl of fiber formhydrogen bonds, while its quaternary ammonium cation group together with fiberswith negative charge form ionic bonds, its sulfo group will co-ordination complexwith Al3+in Al2(SO4)3the retention aid, at the same time, the complex Al3+formcoordinate bond with fibers in paper. With the help of amphoteric P(DMC/AM/AMPS)and the retention aid Al2(SO4)3, cross-linked network between fibers come into being,and this kind of cross-linked network tends to become dense along with the additionof amphoteric polyacrylamide, thus the strength index such as tensile index, tearingindex and burst index will become stronger.