Suspension polymerization process is commonly used to produce expandable polystyrene. In the conventional method for producing this polymer, two different initiators are added to the process at two different temperature levels. In the industrial scale, this process is time consuming and difficult to control. A new method (Multi-Stage Initiator Dosing, MID) is proposed, in which, the initiator i...

atom transfer radical polymerization (atrp) of styrene was carried out at 105°c and a monte carlo simulation was employed to model the system. the variations of monomer conversion, the initiator concentration, average molecular weight, and molecular weight distribution were evaluated as the reaction proceeded. according to the results obtained, for similar reaction time, monomer conversion is h...

in suspension polymerization, particle size distribution of polymer is the outcome of dynamic equilibrium between the break up and coalescence phenomena. the rates of break up and coalescence and consequently polymerization stability depend on several parameters, the most important of which are type and concentration of stabilizer. in this study, the effects of type and concentration of stabili...

Cloisite Na+was used as a solid surfactant (stabilizer) in Pickering emulsion polymerization of styrene-co-butyl acrylate in presence of oil soluble initiator, azobisisobutyronitrile (AIBN) and water soluble initiator, potassium persulfate (KPS). Fourier transform infrared (FTIR) spectrum approved the corporation of Cloisite Na+ layers within the polymer matrix. Effect of clay content was a...

styrene polymerization through frp and atrp methods was carried out at 110oc, while in-depth studies were performed by monte carlo simulation.the changes in monomer conversion, initiator concentration, average molecular weight, and polydispersity index were computed over the course of the polymerization. as the results indicate, compared to atrp, the frp reaches higher conversion in a similar r...

kinetics of radical polymerizations of waterborne alkyd/acrylic hybrid resin via batch mini-emulsion technique was studied using redox initiators (tbhp/fe2+/edta/asac  and  tbhp/fe2+/edta/sfs) at relatively low temperatures and thermal initiators (bpo, kps and aibn) at higher temperatures to seek the most suitable initiator system. at the end of all reactions the unreacted monomer content was r...

The aim of this study was to evaluate the influence of an onium salt in the polymerization kinetics of a dental adhesive model resin. A monomer mixture, based on Bis-GMA, TEGDMA and HEMA, was used as a model dental adhesive resin, which was polymerized using camphorquinone (CQ) as a photo-initiator in addition to either binary or ternary photo-initiator systems. The binary systems were formulat...

polyacrylontrile synthesis, via atom transfer radical polymerization, is studied in various initiator concentrations, transitional metal catalyst and different concentrations of cubr2. the variations of monomer conversion and the lin-earity of semi-logarithmic kinetic profile which is the evidence of living polymerization and constant radical concentration in the reaction medium, were revealed ...

Polymers with a low molecular weight derived from soybean oil have been prepared in a supercritical carbon dioxide medium by cationic polymerization. Boron trifluoride diethyl etherate was used as an initiator. Influences of polymerization temperature, amount of initiator, and carbon dioxide pressure on the molecular weight were investigated. It is shown that the higher polymerization temperatu...

Polymer nanocomposites of core–shell structure were prepared by grafting poly(methyl methacrylate) (PMMA) from TiO2 nanoparticle via the surface-initiated polymerization (SIP) strategy. A bifunctional polymerization initiator inspired by L-3,4-dihydroxyphenylalanine (DOPA), a key constituent of mussel adhesive proteins (MAPs), was designed and synthesized for use in SIP from oxide surfaces. The...