Cumulative Copolymer Composition Research Articles

Graft polymers with macromonomers. II. Copolymerization kinetics of methacrylate‐terminated polystyrene and predicted graft copolymer structures

AbstractCopolymerization studies of methacrylate‐terminated polystyrene macromonomers (M1) with several comonomers (M2) verified the modified kinetic scheme and permitted prediction of graft polymer compositions and structures. Instantaneous and cumulative copolymer compositions, average graft distributions, and grafts per molecule are predicted from FORTRAN IV or BASIC programs. The r2 relative reactivity ratios determined from styrene copolymerization (0.61) or from low conversion acrylic monomer in aqueous suspension (∼0.4) had good agreement with literature values (about 0.6 and 0.4, respectively). Decreased macromonomer reactivity determined at high acrylic monomer conversions was attributed to phase separation phenomena. The Macromers also exhibited lower reactivity than predicted when copolymerized with acrylic monomers in DMSO/benzene solutions (r2 ∼ 0.8).

MULTIPLICITY OF STATES IN CONTINUOUS STIRRED COPOLYMERIZATION REACTORS: ITS EXISTENCE AND CONSEQUENCES

Abstract The dynamic behaviour of a continuous copolymerization stirred tank reactor is analyzed. The evolution of multiple steady states due to Trommsdorf or gel effect in free radical bulk copolymerization systems is illustrated for the first time taking into consideration the changes in the cross termination rate constant [or the φ factor] at high extent of reaction. The effect of concentration multiplicity on cumulative copolymer composition is illustrated. The consequences of the results of the present analysis in copolymerisation reactor operation and design have been discussed.

A method of calculating copolymerization reactivity ratios

AbstractAn improved linearization method is proposed for determining the monomer reactivity ratios of free‐radical copolymerizations by fitting the data of cumulative copolymer compositions and overall weight fractional conversions, or cumulative copolymer compositions and residual monomer compositions of the reaction mixture. The reactivity ratios of monomers for four different copolymerization reactions are determined. The results are very close to those of literature reports and account well for the experimental results.

Monte Carlo simulation of copolymerization and compositional inhomogeneity of copolymers: comparison to experimental data

A review is given of the methods used to calculate copolymer composition as a function of chain length. A Monte Carlo simulation of copolymerization, which considers the initiation and propagation steps and yields cumulative copolymer composition as a function of chain length, is described in detail. The results of the simulations for three copolymer systems show that the initiation step significantly influences the short chains but its effect rapidly vanishes with increasing chain length. The results of the simulations for the three copolymer systems are compared to experimentally determined composition-chain length distributions. The agreement of the simulations and the experimental data is good for long chains but poor for short chains.