PhD student-First principles design of mediating agents for controlled radical (co)polymerization - Belgium
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Posted on : 08 March 2017
- Explore the use of quantum chemical calculations to obtain reliable kinetics for the reactions involved in free, RAFT and NMP controlled radical (co)polymerization, which allows to assess the influence of the chemical structure on the performance of a range of RAFT and NMP mediating agents.
- The results allow to formulate optimal combinations of mediating agent and polymerization conditions to synthesize targeted functional (co)polymers.
- The calculated rate coefficients can be implemented in available microkinetic models and validated by comparison of simulation results with experimental data.
- Sophisticated macromolecular architectures that meet predefined end-use properties have a tremendous potential for a variety of high-tech applications and can, in principle, be synthesized using controlled radical polymerization (CRP) techniques that do not require industrially unattractive stringent oxygen or water free environments or highly purified reagents.
- In CRP, a mediating agent is added to reversibly capture macroradicals in a dormant state preventing the uncontrolled growth that is typical for conventional free radical polymerization (FRP).
- Full control of the detailed chemical structure of the individual macromolecules can only be accomplished within a very narrow window of process conditions since it requires that throughout the polymerization the rates of the various elementary reactions are carefully balanced which introduces the need for dynamic synthesis protocols that allow an instantaneous control of reactant concentrations and temperature.
- This rate control pertains not only to initiation, propagation and termination reactions but more importantly also includes activation/deactivation reactions involving the mediating agent and possible side reactions.
- To elucidate and quantify the effect of the molecular structure of the monomer and the mediating agent on the chemistry and the reactions rates, cutting edge quantum chemical techniques can be used to assist in obtaining intrinsic rate coefficients as a complement to experiment and, hence, to contribute to an accelerated optimization of controlled polymerization processes and design of functional polymer material.
- First, an appropriate computational method is to be selected to calculate reliable activation/deactivation and propagation rate coefficients for a limited range of well-established vinylmonomers (e.g. styrene, MMA). In a second step, this method will be applied to evaluate rate coefficients for activation/deactivation, propagation and possible side reactions for a broad range of potential RAFT and NMP mediating agents and vinylmonomers., focussing on vinylmonomers relevant for the synthesis of polymers with high-tech and biomedical applications.
- Next to that, an evaluation of the effect of the chain length and the solvent on the intrinsic rate coefficient is to be performed.
- Validation of the calculated rate coefficients will be performed in close collaboration with the ongoing experimental and model development work in the group.
- Evaluation of the performance of the candidate RAFT and NMP mediating agents will be performed by implementing the calculated rate coefficients in available microkinetic models to simulate conversion and (co)polymer microstructural characteristics.
- In a second stage, the rate coefficients will be used to design optimal combinations of promising mediating agent, monomer and polymerization conditions to synthesize targeted functional (co)polymers that are to be validated by experiment.
- Funding: Long Term Structural Methusalem Funding by the Flemish Government
Profile of the Candidate
- Applicants must possess a MSc in Chemical Engineering or related subject and a TOEFL certificate with a minimum score of 95(iBT) or equivalent.
- Relevant experience in the area of reactor engineering, kinetics, and/or computational chemistry is strongly recommended.
- Candidates must have a strong mathematical background and be willing to focus on obtaining quantitative rather than qualitative results.