Study On Paper Strengthening Agent By Esterification Of Cellulosic Fines

In this paper,the paper reinforcing agents were prepared by esterificating fines with three benzoic acid or citric acid.Then the paper reinforcing agents were analyzed by IR,AFM,elemental analysis,and the effect of reinforcing agent on the properties of paper was evaluated.The optimal condition of TMF and CMF compound with cationic starch and PAE were also studied.The results show that the carboxyl content of the TMF can be effectively improved,and the TMF can improve the performance of the paper.When the amount of three formic acid was 10%(for short fiber dry mass percentage),the pH was 5,the amount of TMF was 1%,the improvement of properties of paperwas best,compared with the control samples,the tensile index,burst index and tear index were increased by 57.94%,11.08%,78.30%.Under this condition,the study on the performance of recycled paper showed that tensile index,tear index,bursting index and folding resistance were increased by 10%,5.14%,6.97%,and 45.76%,respectively.The carboxyl group content of CMF was obviously improved.When the amount of citric acid was 7%(for short fiber dry mass percentage),the pH was 5,the amount of CMF was 1%,the improvement of properties of paperwas best,compared with the control samples,the tensile index,burst index and tear index were increased by 60.32%18.25%,146.23%.Under this condition,the study on the performance of recycled paper showed that tensile index,tear index,bursting index and folding resistance were increased by 7.70%,7.35%,15.54%,155.93%.When the TMF and CMF were respectively mixed with PAE and cationic starch,the properties of paper were improved.The results showed that the optimum compound ratio are as follows:the optimal mixed ratio of TMF and cationic starch was 0.5%:0.5%;the optimal mixed ratio of TMF and PAEwas 0.7%:0.5%;the optimal mixed ratio of CMF and cationic starch was 0.3%:0.5%;the optimal mixed ratio of CMF and PAE was 0.5%:0.5%.Scanning electron microscopy showed that adding paper strengthening agent can reduce the gap between the paper fiber and enhance binding between the fibers;atomic force microscope showed that the TMF and the CMF were nanoscale particles,which can enhance the properties of paper.