Continuous styrene – methyl methacrylate – glycidyl methacrylate terpolymerizations in homogeneous mixtures with supercritical carbon dioxide

Abstract

Free‐radical terpolymerizations of styrene, methyl methacrylate, and glycidyl methacrylate were carried out in a tubular reactor in the presence of 20 wt.% CO2 at temperatures between 120 and 180°C and pressures of 300 and 350 bar. The number average molecular weights, MN, were mostly between 2000 and 3000 g·mol−1 and polydispersity indices around 2. In part of the experiments molecular weights were controlled by n‐dodecyl mercaptan serving as the chain‐transfer agent. PREDICI modeling indicates that the targeted molecular weights of MN∼2500 g·mol−1 and polydispersities around 2 may also be reached by using an initiator cocktail, a mixture of two initiators with significantly different decomposition rate coefficients. The predictions are confirmed experimentally.

Homogeneous Phase Copolymerizations of Vinylidene Fluoride and Hexafluoropropene in Supercritical Carbon Dioxide

“…[8,9] Moreover, continuous processes are attractive with respect to integral processes that combine polymer synthesis with subsequent steps such as formulation or shaping of the polymer. With respect to the VDF-HFP copolymers of this study particle generation from supercritical solution may be considered.…”

“…For example, styrenemethacrylate copolymers serving as model compounds for acrylic binder materials were obtained in a tubular reactor set-up. [8,9] Although the solubility of most polymers in scCO 2 is limited, the presence of fluorocarbon pendent groups on a hydrocarbon backbone was shown to be advantageous for the homogeneity of fluoropolymer/scCO 2 systems. [10][11][12] Fahmy reported on the influence of HFP on the PVDF-CO 2 phase behavior.…”

A Comparison of Modeling Approaches for Dispersion Homopolymerization of MMA and Styrene in Supercritical CO2

“…The groups of Kiparissides28 and Morbidelli29 have modeled the dispersion homopolymerization of MMA in scCO 2 . The group of Morbidelli30 has also modeled the homopolymerization of VDF as a heterogeneous process, being able to describe situations with bimodal molecular weight distributions, as observed by Saraf et al26 The effect of using a cocktail of initiators in the free‐radical terpolymerization of styrene, MMA and glycidyl methacrylate in a tubular reactor, in the presence of scCO 2 at 120 and 180 °C was studied experimentally and by a simulation study using the software Predici® 31. The modeling of dispersion copolymerization with crosslinking of vinyl/divinyl monomers in scCO 2 32 and the modeling of homogeneous production of fluoropolymers33 has been addressed by our own group.…”