The Modification Of Pcc With Phosphorylated Chitosan And Application In Papermaking

In this study PCC was modified with phosphorylated chitosan aimed to improve the retention rate of PCC in the process of papermaking and improve the physical strength of paper with PCC filler.Firstly, phosphorylated chitosan was synthesized starting from chitosan, P2O5and CH4O3S by esterification reaction. The effects of reaction temperature, P2O5dosage,reaction time and amount of CH4O3S on the degrees of substitution of products were discussed by orthogonal test. The results indicate that the optimum conditions were reaction temperature5℃,(m(chitosan):(m(P2O5)=1:1, amount of CH4O3S12mL. phosphorylated chitosan was prepared by change the reaction time and various degrees of substitution (DS) were obtained which color is characterized by shallow. The results of solubility experiment showed that phosphorylated chitosan with degrees of substitution around0.6-1.0were dissolvable in water. The analysis methods of phosphorylated chitosan were Fourier infrared spectrum, scanning electron microscope, the results showed that the phosphate radical was successfully grafted to chitosan.Secondly, The effect of different processing conditions of phosphorylated chitosan modified PCC were discussed. The result shows that the optimization process were5%modifier dosage, reaction pH7.5, mixing speed300rpm, reaction time40min, reaction temperature40℃, concentration of PCC10%. The analysis of the SEM photos and Fourier transform infrared spectrum showed that the phosphorylated chitosan successfully coated on the surface of PCC.Finally, modified PCC filler retention rates and the performance of paper using filler were studied. The result shows that the retention rate of modified PCC higher than unmodified PCC5.14percent. The tensile index, tear index and burst index of paper filling with modified PCC were higher than paper filling with unmodified PCC8.43N· m/g and0.38mN· m2/g and0.46Kpa· m2/g. but compared with paper filling unmodified PCC, the whiteness of paper filling with modified PCC decreased0.39percent. The reaction mechanism was discussed. The results showed that the bonding strength of fibers and modified PCC could be efficiently increased.