Using trihydroxymethyl propane triacrylate (TMPTA) and styrene (St) as the monomers and 2

2-azobis-(isobutyronitrile) (AIBN) as the initiator

uniform and crosslinked microspheres of P(TMPTA-St) were prepared through precipitation polymerization in ethanol.Monomer conversion

yields of microspheres and soluble oligomers were determined

size and size distribution of the microspheres were examined by scanning electron microscope.Results indicate that uniform microspheres were obtained with 10 wt% to 60 wt% of TMPTA in the monomers with a yield of about 50% for the microspheres at 60 wt% of TMPTA.Monomer conversion and microsphere yield were increased with TMPTA amount.Increase in AIBN was also useful to increase monomer conversion and microsphere yield; the soluble oligomers were also increased at the same time.By adding water in ethanol while keeping AIBN at 2 wt% relative to the monomers

monomer conversion of above 90% was achieved with the yield of the microspheres at about 83%.An optimized protocol

by which about 98% of monomer conversion and 90% of uniform microspheres were achieved

is recommended

in which 26 vol% of water was added to ethanol as the polymerization solvent combined with 6 wt% of AIBN.The results were interpreted and the mechanism of the polymerization was discussed.