polybutadiene nanoparticles were synthesized via batch emulsion polymerization of butadiene in the presence of potassium persulfate, disproportionate rosinate potassium cation and t-dodecyl mercaptane as initiator, emulsifier and chain transfer agent, respectively. polymerization reaction was performed at different temperatures (60, 70 and 80 °c). conversion was measured at the various time int...

in this work, based on experimental observations and exact theoretical predictions, the kinetic scheme of raft polymerization is extended to a wider range of reactions such as irreversible intermediate radical terminations and reversible transfer reactions. the reactions which have been labeled as kinetic scheme are the more probable existing reactions as the theoretical point of view. the deta...

the data on the effect of ethylene concentration on polymerization rate for several modifications of modern highly active titanium–magnesium catalysts ticl4/mgcl2 are presented. these catalysts differ in titanium content and conditions of support preparation, activities, and the shape of kinetic curves. it is found that the observed order of polymerization rate with respect to ethylene in the r...

atom transfer radical polymerization of styrene (st) and methyl methacrylate (mma) was performed at 90oc in the absence and presence of nanoclay (cloisite 30b). trichloromethyl-terminated poly(vinyl acetate) telomerand cucl/ pmdeta were used as a macroinitiator and catalyst system, respectively. the experimental results showed that the atom transfer radical polymerization of st and mma in the a...

In free-radical polymerization, a monomer-initiator mixture is converted into a polymer. Depending on initial and boundary conditions, free-radical polymerization can occur either in a bulk mode (BP) or in a frontal mode (FP) via a propagating selfsustaining reaction front. The main goal of this paper is to study the role that bulk polymerization plays in frontal polymerization processes for va...

a new model based on a combination of the polymeric multigrain and multilayer models has been developed to predict the polymerization rate, particle growth, morphology, effective parameters on broadening of the molecular weight distribution, number and weight average of the molecular weight, isotacticity index and bulk density of polymer. mathematical correlations and the kinetics used in this ...

in this study, the slurry polymerization of ethylene over ticl4/mgcl2/alet3 was obtained. firstly, to obtain the optimum value of [al]/[ti], the effect of [al]/[ti] on polymerization rate and catalyst yield was studied. also, the effect of catalyst content on yielding, crystallization, melting point and density of product were obtained. to determine the order of reaction, the monomer pressure w...

ethylene was polymerized in slurry phase over a ticl4/mg(oc2h5)2 catalyst activated by al(c2h5)3. it was shown experimentally that mass transfer resistance has no effect on polymerization kinetics. after estimation ofthe active site concentration by inhibition method with carbon monoxide, the effects of polymerization temperature, monomer and cocatalyst  oncentrations and hydrogen were investig...

in the present work, a titanium-based ziegler-natta catalyst was employed to synthesize ultra molecular weight polyethylene in a slurry medium. the effect of different parameters such as ethylene pressure, temperature, catalyst composition, and hydrogen pressure was studied. as the results indicate, increasing either [al]/[ti] ratio or temperature causes polymerization rate to go through a maxi...

a new potassium persulfate redox system has been investigated for the graft polymerization of vinyl monomers. in this study potassium persulfate system was used for initiation the polymerization. graft polymerization of acrylonitrile (an) onto starch (sta) was carried out in aqueous solution using potassium persulfate (i) redox system. it was found that the percentage of grafting and rate of gr...