| Because of the shortage of wood resources in china, the lower sheet grammage and the higher filler addition, the paper industry is facing the decrease of the paper strength (especially the wet strength). This thesis studies the preparation of PAE resin and its modificated product, which is suitable for the modern papermaking. PAE resin contains humful AOX, which restrict its development as paper wet strength agent. To prepare Low-AOX PAE, this paper introduced double bonds to the molecular structure of PAE. And the sharing system of PAE resin and anionic material was studied.This paper studied the influence of the PAE resin containing low content of AOX, unsaturated PAE resin and PAE/CMC binary sharing system on the strength, especially wet strength of paper systematically, by using bleached softwood and bleached hardwood pulp as raw materials.First, the synthesis conditions of PAE resin contained low content of AOX was studied. The results showed that the best synthesis conditions of PAE resin was: the temperature of synthesis of PPC, the first heated to 160℃, reaction for 3h, then heated to 190℃, reaction for 1h, acid-amine molar ratio of 1:1; the temperature of synthesis of PAE, heated to 60℃, EPI / PPC molar ratio of 1.1, pH value = 9, this time the content of the organic chlorine was 0.145%. By FT-IR analysis, PAE structure contained the sec-amide C=O bond and the sec-amide N-H bond, this mass was proved as PAE resin. The results also showed that PAE resin was more suitable for using under alkaline conditions, in alkaline conditions, the retention rate reached 26.5% after high-temperature ageing, the wet strength was nearly three times as un-aging. The burst index reached 4.49 kPa·m2/g and the tear index reached 13.9 mN·m~2/g.Second, the unsaturated PAE by generated acrylic modified PAE resin was studied. The results showed that the best conditions of synthesis of the unsaturated PAE was the reaction temperature of 60℃, alcohol amine molar ratio of 2.4, PTSA as catalyst, this time the graft efficiency was more than 98%. By FT-IR analysis, the 1729cm-1 appeared the C=O stretching vibration, 1174cm-1 appeared the C (C = O)-O stretching vibration, described the graft copolymerization of PAE and AA has occurred. By FT-RAMAN spectroscopy, the strong absorption peak at the 1635cm-1 proved that C=C has existed, and the double bond was not destroyed.The results also showed that unsaturated PAE resin at different pH conditions had different Zeta potential. The adsorption of unsaturated PAE resin to fiber under alkaline conditions was stronger, in the 3% added the wet tensile index reached 18.2 N·m/g, the retention rate was 30% (high-temperature curing), compared with saturated PAE resin 15.8 N·m/g, increased by 2.4 N·m/g. And by comparing the high-temperature aging and UV curing, found that in alkaline conditions, when the added amount of unsaturated PAE resin was 3%, the wet tensile strength index reached 21.2N·m/g, the retention rates reached 34.9%.Next, the binary sharing system of PAE and CMC was studied. The result showed that 1.0%PAE+0.3%CMC sharing system was the best and the wet tensile index reached 16.4 N·m/g,. Compared with 1.0%PAE added, wet strength retention increased 27.1% and was even higher 0.6 N·m/g than that added with 2.0% PAE. The retention rate was as higher as 28.4% and the burst index and tear index were increased by 39% and 11% respectively compared with the blank sheet.Finally, the effects of saturated PAE, unsaturated PAE resin and PAE/CMC sharing system on the strength of paper were compared. When the optimal level was added, unsaturated PAE resins (UV aging) has the best result. The wet strength retention rate was 34.9%. Followed by 1% PAE +0.3% CMC (high-temperature aging), the retention rate was 28.4%; the smallest retention rate was 26.3% by saturated PAE resin (high-temperature aging). The results shows that the modificated PAE has higher paper wet strength efficiency and lower AOX dischargement. Moreover, it can be cured by UV ray instead of high temperature curing.
|
PDF Full Text Request