Copolymerization of VDF and HFP in Supercritical Carbon Dioxide: A Robust Approach for Modeling Precipitation and Dispersion Kinetics

Abstract

A kinetic model is developed for the heterogeneous free-radical copolymerization of vinylidene fluoride and hexafluoropropylene in supercritical CO 2. The model accounts for polymerization in both the dispersed (polymer-rich) phase and in the continuous (polymer-free) supercritical phase, for radical interphase transport, diffusion limitations, and chain-length-dependent termination in the polymer-rich phase. A parameter evaluation strategy is developed and detailed to estimate most of the kinetic parameters a priori while minimizing their evaluation by direct fitting. The resulting model predictions compare favorably with the experimental results of conversion and MWD at varying monomer feed composition, monomer concentration, interphase area, and pressure of the system. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Synthesis of Poly(N-vinylcaprolactam)-Based Microgels by Precipitation Polymerization: Process Modeling and Experimental Validation

“…In the literature, only a few models are proposed that describe precipitation copolymerization, ,, all addressing different polymer systems. For the synthesis of microgels, only few models have been proposed, which are restricted to PNIPAM-based microgels.…”

“…In the literature, only a few models are proposed that describe precipitation copolymerization, 23,27,28 transmission electron microscopy (TEM) images shows that kinetics can be utilized to approximate the internal structure of the microgels. 16 Although the influence of a variety of reaction parameters, including cross-linker concentration and type, on PVCL-based microgels has been studied (see, e.g., refs 29 and 30), a model for the synthesis of PVCL-based microgels has not been described up to this point.…”

Solution of population balance equations by logarithmic shape preserving interpolation on finite elements

“…For this reason, the differential equation set, known as population balance equations (PBE), has been used extensively since its formal introduction. [7,8] PBE have been employed to rationalize polymerization reactions [9,10,11,12,13,14,15,16,17,18,19,20,21], colloid aggregation, [22,23,3,24,25,26,27,28] and crystallization processes [29,30,31,32,33]. This short list proves the versatility of the PBE, that enable the description of virtually any type of population, focusing on some key property such as the number of monomeric units in polymer chains, or the size of crystals.…”