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Porous acrylonitrile (AN)/itaconic acid (IA) copolymers were successfully prepared by suspended emulsion polymerization for the first time, with potassium peroxydisulfate (KPS) as an initiator, poly(vinyl alcohol) (PVA) as a dispersant agent, and Span80 as an emulsifier. The effects of the water/monomer mass ratio, agitation conditions, KPS concentration, PVA concentration, Span80 concentration,s and IA concentration on the average particle size and size distribution, particle morphology, and porosity of the AN/IA copolymers were investigated. The results show that the final AN/IA copolymers formed with agglomerates of primary particles had a porous structure, low particle density, and uniform particle size and did not agglomerate easily between the particles. The preparation conditions for the AN/IA copolymers were optimized as follows: (1) the water/monomer mass ratio was 0.3 : 1; (2) the concentrations of KPS, IA, PVA, and Span80 were 0.5, 12.4, 0.1, and 0.5 wt %, respectively, based on the weight of AN separately; (3) the agitation rate was 400 rpm; (4) the polymerization temperature was 70°C; and (5) the reaction time was 3 h. The size of the final AN/IA copolymer particles was in the range 200–400 μm. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Highly crosslinked poly(styrene-co-divinylbenzene) microspheres with a 1.0–2.5-μm diameter were prepared by precipitation polymerization in neat acetonitrile. The effects of various polymerization parameters such as the monomer and initiator concentration, comonomer composition, and cosolvents on the properties of the resulting particles were studied. The particle diameter increased with the monomer concentration, whereas the particle size distribution remained almost constant. The resulting yield of the particles reached 41.1% when 6 wt % 2,2′-azobisisobutyronitrile (based on the total monomer) was used as the initiator. The styrene fraction in the monomer composition and toluene fraction in the solvent mixture also significantly affected the morphology and size of the resulting particles. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Monodisperse crosslinked polystyrene microspheres were prepared by the dispersion copolymerization of styrene and divinylbenzene in a mixed solvent of ethanol and H2O. 2,2′-Azobisisobutyronitrile and poly(N-vinyl pyrrolidone) were used as the initiator and steric stabilizer, respectively. The crosslinker-postaddition method was adopted through a slow addition of a crosslinking agent into the dispersion system at a certain time after the beginning of the polymerization. The effects of the postaddition recipe, postaddition beginning time, postaddition velocity, and agitation rate on the particle size, size distribution, and morphology were discussed. The resulting polymer microspheres were characterized with scanning electron microscopy and laser particle analysis. Crosslinked polystyrene microspheres with a narrow size distribution and a 12.0% crosslinker level were obtained with a size of 1.0 μm through the crosslinker-postaddition method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008

Acrylonitrile(AN) was successfully used to copolymerize with itaconic acid (IA) by suspension emulsion polymerization at 70 ˚C under N2 atmosphere for the first time. Porous AN/IA copolymers were prepared by using potassium peroxydisulphate (KPS) as initiator, poly(vinyl alcohol) (PVA) as dispersant and Span60 as emulsifier. Kinetics of suspension emulsion copolymerization of AN with IA were studied. Effects of various mass ratios of water/monomer, initiator concentrations, emulsifier concentrations and dispersant concentrations on AN/IA copolymerization rate and changes of particle size and size distribution with the extension of polymerization time were investigated. It was found that the copolymerization rate increased with water/monomer mass ratio and KPS concentration. Span60 concentration and PVA concentration had no obvious effect on the polymerization rate. Finally, a suspension emulsion polymerization mechanism for AN and IA was proposed.