Study On New Wet Strength Dissociative Agent And Its Mechanism Of Action

The purpose of this thesis is to develop a new effective wet strength dissociative agent and to optimize the process conditions of regenerated pulping of different wet strength paper.At the same time,the mechanism of action of the new dissociative agent was studied.In this paper,the optimal conditions of PAE wet-strength paper crushing process without additives were first studied,which were 2 h prepreg time,60℃ prepreg temperature and 15%pulp crushing concentration.The application effect of aluminum sulfate,sodium hypochlorite,magnesium sulfate and LL dissociative agent on PAE and MF wet strength paper was studied.For PAE wet strength paper,in terms of yield of accept pulp,aluminum sulfate 82%,sodium hypochlorite 90.21%,magnesium sulfate 82.1%,LL dissociative agent 95.93%.In terms of cost,it takes 46.82 yuan of aluminum sulfate,141.15 yuan of sodium hypochlorite,14.61 yuan of magnesium sulfate and 54.21 yuan of LL dissociative agent to produce a ton of accept pulp.In terms of paper performance,the tearing index of the four additives did not change significantly,and the tensile index of LL dissociative agent was 35.1 N·m·g-1 at most.For MF wet-strength paper,in the yield of accept pulp,aluminum sulfate 95.81%,sodium hypochlorite 86.3%,magnesium sulfate 95.12%,LL dissociative agent 91.51%.In terms of cost,the production of a ton of accept pulp requires aluminum sulfate 10.01 yuan,sodium hypochlorite 451.91 yuan,magnesium sulfate 6.31 yuan,LL dissociative agent 227.3 yuan.In terms of paper performance,the tensile index of the four additives did not change obviously,and the maximum tearing index of aluminum sulfate is 22.92 mN·m2·g-1.The above results show that the LL dissociative agent is more suitable for PAE wet-strength paper,and it has obvious advantages over conventional auxiliary agents in the aspects of yield,paper performance and application conditions.The magnesium sulfate is more suitable for MF wet strong paper,a higher yield can be achieved and the cost of is lower,but the strength of recycled paper is slightly less.The effect of LL dissociative agent on waste fruit bag paper was studied.When the dosage is 1%,the maximum yield is 92.13%,and the maximum tensile and tearing indexes are 40.8 N·m·g-1 and 7.49 mN m2·g-1,and the auxiliary agent require 52 yuan.Compared with traditional auxiliaries,it has obvious advantages in the yield of accept pulp and the performance of paper,and the cost is relatively low.The mechanism of LL dissociative agent was studied.Through the analysis of infrared spectra and scanning electron microscopy,it was found that LL dissociative agent mainly destroyed the tertiary amine covalent bond formed by the self-crosslinking of PAE resin.