Preparation and performance of retention and drainage aid made of cationic spherical polyelectrolyte brushes

Abstract

Abstract Spherical polymer brushes were synthesized by grafting acrylamide from the surface of γ-methacryloxypropyl trimethoxy-silane-modified SiO2 nanoparticles. Then, cationic spherical polyacrylamide (CSPAM) brushes were obtained by a manniched polyacrylamide (PAM). Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, and gel permeation chromatography were introduced to analyze the structure, morphology, and molecular weight of CSPAM, respectively. The effects of pH and the dosage of CSPAM on the flocculation of fine pulp and precipitated calcium carbonate were studied. Furthermore, the optimal drainage performance could be achieved when the beating degree (°SR) decreased by about 14.42% with the dosage of CSPAM of 2 mg·g−1. The retention effect of CSPAM revealed that the highest first-pass retention was 71.1% when the dosage of CSPAM was 3.5 mg·g−1. In addition, the mechanism of retention and drainage of CSPAM was discussed.