The applications of cationic polymeric microparticles in papermaking

摘要

Cationic polymeric microparticles (CPMP) with different charge densities and colloidal properties were prepared from emulsion and solution polymerization techniques. The applications of the CPMP in papermaking were studied. It was found that the combination of cationic polymeric microparticles with a cationic or anionic polymer could significantly improve the flocculation and retention efficiency. For the dual-flocculant system of CPMP and anionic polymer, the CPMP may first form cationic patches on the substrate surface, and then the anionic polymer forms bridges through these patches. For the dual-flocculant system of CPMP and cationic polymer, the preadsorption of cationic microparticles may affect the conformation of the polymer on the substrate surface. The charge repulsion between preadsorbed cationic microparticle and cationic polymer may prevent the polymer from getting flat on the substrate surface; thus the flocculation efficiency of cationic polymer can be significantly improved through more effective bridge flocculation. The CPMP can also be effective internal sizing agents. Results indicated that the sizing performance was the function of copolymer addition level, charge density, and particle size. The improved optical and mechanical properties were also observed on sized handsheets.