Synthesis and property behavior of dioctyl phthalate plasticized styrene–acrylate particles by Shirasu porous glass emulsification and subsequent suspension copolymerization

Abstract

Two-phase model styrene-acrylate copolymers were synthesized with a soft phase consisting of methyl acrylate, butyl acrylate, and butyl methacrylate. Besides the styrenic copolymers, copolymers containing a hard phase of methyl methacylate and methyl acrylate were also synthesized. Comonomer droplets with a narrow size distribution and fair uniformity were prepared using an SPG (Shirasu porous glass) membrane having pore size of 0.90 m. After the single-step SPG emulsion, the emulsion droplets were composed mainly of monomers, hydrophobic additives, and an oil-soluble initiator, suspended in the aqueous phase containing a stabilizer and inhibitor. These were then transferred to a reactor, and subsequent suspension polymerization was carried out. Uniform copolymer particles with a mean diameter ranging from 3 to 7 m, depending on the recipe, with a narrow particle size distribution and a coefficient of variation of about 10% were achieved.Based on the glass-transition temperatures, as measured by differential scanning calorimetry, the resulting copolymer particles containing a soft phase of acrylate were better compatibilized with a hard phase of methyl methacrylate than with styrene with dioctyl phthalate (DOP) addition. Glass-transition temperatures of poly(MMA-co-MA) particles were strongly affected by the composition drift in the copolymer caused by their substantial difference in reactivity ratios. Incorporation of DOP in the copolymer particles does not significantly affect the glass-transition temperature of MMA-or MA-containing copolymer particles, but it does affect the St-containing copolymer and particle morphology of the copolymers.

Manufacture of poly(methyl methacrylate) microspheres using membrane emulsification

“…It is clear that the particle size distribution matches closely the precursor oil monomer droplet characteristics in both cases. This is consistent with a number of earlier studies concerning the use of ME technologies for the preparation of precursor droplets in a suspension polymerization process [16][17][18][19][20]. The absence of agglomeration between droplets/particles during the polymerization process suggests that the added PVA is as effective as a steric stabilizer.…”

“…Despite this, stable dispersions of PMMA particles with diameters ranging from 3 to 35 µm were reported with a typical coefficient of variation (CV) of 10%. Later work from the same group describes a single-stage process for the emulsification of MMA prior to the subsequent polymerization reaction, although details of what had been modified to achieve this were not provided [18,19]. We assume here that the wettability of the membrane had been adjusted although this was not explicitly stated.…”

Two‐stage stabilizer addition protocol as a means to reduce the size and improve the uniformity of polymer beads in suspension polymerization

“…In recent years, there has been significant research in decoupling emulsification and polymerization stages in suspension polymerization. Microfluidics and membrane emulsification methods have been suggested as a substitute to the emulsification stage in a typical suspension polymerization. While microfluidic systems enjoy unrivalled superiority in terms of drop uniformity, they suffer from a lack of scalability and high cost, which makes them an impossible choice for many commodity polymer beads.…”

Protein binding properties of surface-modified porous polyethylene membranes

“…The formation of highly charged centers within the polymer chains of polyelectrolytes in solution leads to strong interactions between polyelectrolytes and solids with oppositely charged surfaces [17][18][19]23]. Many applications involving polyelectrolytes such as water treatment and paper processing are centered around this strong electrostatic interaction and consequential adsorption of the polymer onto charged surfaces [20][21][22][23][24][25][26][27][28]. Because the surface adsorption of polyelectrolytes is electrostatic in nature and thus reversible, the surface affinity and stability of the polyelectrolyte is highly dependent upon many parameters that include system solvent, solvent pH, surface charge, surface charge density, polyelectrolyte charge, and polyelectrolyte charge density.…”

“…The chemical modification of the sintered polyethylene is accomplished through the use of reactive oxygen plasma to form negatively charged functional groups at the polyethylene surface, the adsorption of a positively charged polyelectrolyte onto the polyethylene surface, and finally, the formation of a polyelectrolyte bilayer by the additional adsorption of a negatively charged polyelectrolyte [16][17][18][19][20][21][22][23][24][25][26][27][28]. The formation of highly charged centers within the polymer chains of polyelectrolytes in solution leads to strong interactions between polyelectrolytes and solids with oppositely charged surfaces [17][18][19]23].…”