A kinetic investigation of styrene/butyl acrylate copolymerization

Abstract

An experimental investigation of the kinetics of the bulk free radical copolymerization of styrendbutyl acrylate initiated with 2.2 '-azobisisobutyronitrile (ABN) was conducted at 50°C using various initiator concentrations and initial monomer ratios including the azeotropic composition.Reactivity ratios were determined by analyzing composition data using the error-in-variables model. The experiments, designed using the Tidwell-Mortimer criterion, were conducted in sealed ampoules at 50°C to low conversion levels From the calculated reactivity ratios, the azeotropic composition was determined and further experiments were run at these conditions as well as at two other initial monomer feed compositions in order to collect composition, rate and molecular weight data. The experiments were run through the full conversion range at two different initiator concentrations.( < 7%).Une recherche expirimentale sur la cinCtique de la copolymerisation a radical libre en vrac du styritne/acrylate de butyle amorcC avec du 2,2 '-azobisisobutyronitrile (AIBN), a Ct C menCe a 50°C avec diverses concentrations d'initiateur et divers rapports de monomkres initiaux, incluant la composition azkotropique.On a determine les rapports de rCactivitC en analysant les donnCes de composition a I'aide du moditle d'erreurs. Les exptriences, mises au point partir du critkre de Tidwell-Mortimer, ont CtC menees dans des ampoules Ctanches 50°C pour de faibles taux de conversion ( < 7%).On a dttermint a partir de rapports de rCactivitC calculCs la composition azCotropique, et de nouvelles experiences ont @tC effectuCes dans ces conditions ainsi qu'i deux autres compositions d'alimentation en monomkres afin d'obtenir des donnCes de composition, de vitesse et de poids moleculaire. Les experiences ont ete menCes dans la gamme de conversion totale a deux concentrations en initiateur diffkrentes.

A kinetic study of free radical copolymerization of styrene/butyl acrylate

“…The reactivity ratio values obtained in this work agree well with those reported by Dubé et al 6) , which fall within the error limits of those estimated from this work. However, there are some discrepancies with other literature values.…”

“…However, there are some discrepancies with other literature values. This fact can be due, as Dubé et al 6) have pointed out, to improper experimental design or to the less accurate analytical methods used in the copolymer composition analysis.…”

“…However, recognizing that the reactivity ratios cannot be known exactly in advance, McFarlane et al 22) suggested to assume values for them that differ from r 1 and r 2 by 20%. Preliminary reactivity ratios, r 1 = 0.95 and r 2 = 0.18, reported by Dubé et al 6) were used. The monomer feed, polymerization time, final conversion and copolymer composition for each sample are shown in Tab.…”

“…In the earliest papers, Arlman et al 1) , Bradbury et al 2) and Gruber et al 3) reported the reactivity ratios. More recently an extensive study of the S/BA system describing both the reactivity ratios and the low conversion copolymerization rate has been carried out by Kaszas et al 4,5) Dubé et al 6,7) have developed a mechanistic model in order to analyze the bulk copolymerization of this system in the full range of conversion. Emulsion copolymerization kinetics data for this system have also been described [8][9][10][11] .…”

A kinetic investigation of styrene/ethyl acrylate copolymerization

“…It has also been shown previously that another likely cause for inaccuracy is improper experimental design. 36 The results were used to plot the instantaneous copolymer composition as predicted by the MayoLewis model. This is shown in Figure 2.…”