The synthesis of monoliths by reversible addition‐fragmentation chain transfer (RAFT) copolymerization of styrene and divinylbenzene (DVB) at high‐crosslinker content is studied using the recently reported multifunctional polymer molecule approach. The agreement between model predictions, incorporating diffusion‐control, and experimental data from CSIRO is good for all cases analyzed. This includes examples with high‐crosslinker concentrations, which cause deviation from some of the simplifying assumptions imposed in the model.
The copolymerization kinetics of hydroxyethyl methacrylate (HEMA) with either ethylene glycol dimethacrylate (EGDMA) or diethylene glycol dimethacrylate (DEGDMA) in the presence of RAFT controllers is studied using a mathematical model recently developed in our group. The model is based on the concept of multifunctional polymer molecules. The cases of conventional and controlled homopolymerizations of HEMA as well as the RAFT copolymerization of HEMA/EGDMA and HEMA/DEGDMA are addressed and are in good agreement with available experimental data. The bulk/solution version of the model is used as first approximation of the behavior of a RAFT dispersion copolymerization of HEMA/ EGDMA carried out in supercritical carbon dioxide.
The effect of microwave irradiation (MI) on the kinetics and molecular weight development in the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) and styrene is studied by using modeling tools. Two models are proposed; one captures the ''microwave effect''' through a microwave-activated radical generation from monomer reaction, besides the typical reactions involved in the polymerization scheme for ATRP, and the other considers non-constant predefined temperature profiles for the polymerization scheme of ATRP (''thermal effect''' model). It is found that both models can reproduce equally well the experimental behavior and performance of several systems reported in the literature. So, more experimental and modeling studies are needed to actually discriminate between the two models.
Two mathematical approaches for modeling of the kinetics and evolution of molar mass distributions in the reversible deactivation radical polymerization of vinyl monomers promoted by redox reaction with N-hydroxyphthalimide (NHPI) and xanthone (XT) are presented. In the first modeling approach, the polymerization scheme is implemented in the standard version of the Predici commercial software. In the second case, an accelerated, self-implemented version of the so called kinetic Monte Carlo (kMC) approach, considering binary trees, is used. The effect of concentrations of XT and monomer, as well as monomer type, on monomer conversion, NHPI efficiency, molar mass averages, molar mass dispersity, and full molar mass distributions are studied. The models are validated using literature available experimental data of polymerizations of methyl methacrylate (MMA) and styrene, in toluene, at 70 °C. The calculated results indicate that NHPI initiator efficiencies are low (<0.2); polymer end-group functionalities present a maximum value of about 0.8 with a subsequent decrease with monomer conversion; molar mass distributions are broad, exhibiting low molar mass tails. In addition, the hypothetical copolymerization of styrene and MMA is also considered. Copolymer composition distributions for short molecules are broader than those for large ones. 2000020 (2 of 12) www.advancedsciencenews.com www.mre-journal.de 2000020 (4 of 12) www.advancedsciencenews.com www.mre-journal.de Figure 7. Copolymer composition of active polymer radicals (plots a and d), dormant polymer (plots b and e), and dead polymer (plots c and f), at 3 and 10 h, respectively, for the reversible deactivation radical copolymerization of Sty and MMA using NHPI and XT.
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