Improving mechanical properties of recycled paper via surface spraying carboxymethyl starch-grafted-polyacrylamide

Abstract

Paper strengthening agent is more and more important in the current papermaking industry. In this study, carboxymethyl starch-grafted-polyacrylamide (CMS-g-PAM) was synthesized via grafting polyacrylamide onto carboxymethyl starch (CMS), and added in a recycled pulp furnish to make handsheets. The structure and surface morphology of CMS-g-PAM were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy. The effects of CMS-g-PAM dosage and addition way on the properties of the paper were investigated. The results showed that CMS-g-PAM could improve the paper mechanical properties through both wet end addition and surface spraying, and surface spraying had a better improvement at the same dosage. CMS-g-PAM was more effective in improving paper mechanical properties than CMS, when it comes to the same addition way and the same dosage. SEM analysis demonstrated that CMS-g-PAM could increase the inter-fiber bonding.