Molecules 2023 , 28 , 7984
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Figure 8. Schematic representations of synthesis process of SPBs ( A ) and cationization process of SPAM( B ). Copied from De Gruyter [193]. Cationic spherical polyelectrolyte brushes (CSPBs), with poly (2-(acryloyloxy) ethyltrimethylammo-nium chloride) chains were grafted from the surfaces of colloidal silica particles by Zhang Xiongzhi et al. [194]. The CSPBs were characterized by various charac- terization methods involving Fourier-transform infrared spectrometry, thermo-gravimetric analysis, transmission electron microscopy, and X-ray photoelectron spectroscopy, as dis- played in Figure 9. And then, the CSPBs were investigated as flocculation and retention-aids for bleached eucalyptus kraft pulp and kaolin/pulp particles. The results suggested that the flocculation and retention-aid properties were improved. Huang Yu et al. [195] reported a dual-component system consisting of CSPBs and anionic polyacrylamide (APAM) to improve the retention and drainage properties of bleached eucalyptus kraft pulp and precipitated calcium carbonate (PCC). CSPBs comprised a silica core and a shell of copolymer of acrylamide (AM) and [2-(methacryloyloxy) ethyl] trimethylammonium chloride (METAC). The CSPB/APAM system showed better retention efficiency than the cationic starch/APAM system under different turbulent conditions. As illustrated in Figure 10, the CSPB/APAM dual-component system interacted with fibers and PCC through a patching and bridging mechanism.
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