Effect of reaction parameters on the particle sizes of crosslinked spherical phenolic beads by suspension polymerization of phenol and formaldehyde

The crosslinked spherical phenolic beads (PB) were prepared with phenol and formaldehyde in alkaline medium by Suspension polymerization technique. Poly(vinyl alcohol) (PVA) hexamethylenetetramine (HMTA), and triethylamine (TEA) were used as stabilizer, crosslinking agent, and basic catalyst respectively. The resulting PB with higher yield (82.5%) and relatively uniform particle size range (0.2-1.8 mm) were formed at 95-97 degrees C, 550 rpm for 4 h, by using varied amounts of PVA as a stabilizer. The particle size and its distribution Could be adjusted by selecting a Suitable polymerization medium, consisting of monomer added to water, and by varying their relative amounts, mechanical agitation and stabilizer concentration. The yield % of 1113 was also varied with the concentration of stabilizer, agitation rate, and monomer-to-water ratio. The effects of concentration of the stabilizer, agitation rates, and monomer-to-water ratio on PB formation and morphology are described. (c) 2006 Wiley Periodicals, Inc.