that high charged polymers adsorb in a flat rather than an A series of cationic polymeric microparticles (CPMP) with difextended conformation. This suggests that, as an effective ferent charge densities and particle sizes were synthesized using bridging flocculant, the optimization of charge density and emulsion or microemulsion polymerization. The interactions molecular weight is very important. However, this is someamong positively charged polymeric microparticles, negatively times difficult because most of the suspension systems are charged fibers, and precipitated calcium carbonate (PCC) particomplicated and varied depending on the conditions. In addicles were studied. It has been found that although CPMP could tion to the polymer getting flat on a solid substrate, the adsorb onto a positively charged PCC particle surface, effective penetration of water-soluble electrolytes into the pores of a flocculation of PCC in water could not be obtained by CPMP solid surface may significantly affect both the dynamics and alone. However, the combination of CPMP with an anionic polyacrylamide (APAM) did significantly improve the flocculation of efficiency of bridging flocculation or patch formation. In PCC. The flocculation mechanics of PCC in this dual flocculation contrast to a water-soluble polymer, the microparticle does system were that the CPMP first created effective patches on the not get flat on or penetrate into a porous particle because of PCC surface, then APAM formed interparticle bridges through its fixed structure. As a result, a more effective patch or positively charged CPMP patches. It has also been found that the bridge may be formed by a microparticle flocculant.
particle size and the surface charge of CPMP are two major factors
The fundamentals of particle bridging flocculation have affecting the flocculation of PCC suspension. The retention of been studied previously (13)(14)(15). These studies clearly PCC on wood fibers using a dual-flocculant system of CPMPshowed that the positively charged small polystyrene parti-APAM was studied, and the related mechanism is discussed here.
cles can strongly bond to the negatively charged large poly-᭧ 1997 Academic Press styrene latex, resulting in a particle bridging flocculation.