Macromolecular Reaction Engineering

Cover: The morphology of hybrid polymer/clay particles synthesized by miniemulsion polymerization has a significant impact on film properties. The morphology of the hybrid droplets controls the morphology achieved upon polymerization, which depends on the interfacial tensions of the modified (hydrophobized) clay with the monomer and aqueous phases. The equilibrium monomer/clay nanodroplet morphologies predicted by means of Monte Carlo simulations as well as experimental evidence of the predicted morphologies in acrylic/montmorillonite nanocomposite latexes are presented. Further details can be found in the article by M. Micǒusǒík, A. Bonnefond, Y. Reyes, A. Bogner, L. Chazeau, C. J. G. Plummer, M. Paulis, and J. R. Leiza* on page 432.

ATRP is a versatile method for synthe-sizing novel value-added materials not accessible with conventional techniques. However, industrial adoption has been hampered by material costs, toxicity and the need for product purification. We present an overview of solution ATRP carried out in a variety of reactor configurations. A chronological summary of select advances made in the literature and in our research group is presented.

The graft copolymer PB-g-PS plays an essential role in the development of the elastomeric phase during the synthesis of high-impact polystyrene. This study aims to provide a better understanding of the effect of the architecture of the graft copolymer on the time required for phase inversion to occur and on the formation of rubber particles, since the graft copolymer acts as a compatibilizer between the continuous PS phase and the rubber subdomains.

Significant benefits of a Bayesian design of experiments over standard experimental design methods are highlighted through case studies applied to NMRP. The ability to incorporate prior knowledge into the design is a distinct advantage. Diagnostic criteria can in parallel shed light on the quality of this prior knowledge and on significant effects. The technique is perfectly general and can be applied to other processes.

The synthesis of high-living/controlled PS by SG1-NMP was investigated. The use of acetic anhydride as additive was tested and the mechanism of acceleration investigated. In all cases the results were not conclusive. The temperature was then decreased. First new SG1-based nitroxides have been used to perform the polymerization at 75 °C. Since these nitroxides were too constrained, the decrease in k_c caused the loss of control. Finally high- and living PS was prepared at 90 °C thanks to the BlocBuilder alkoxyamine.

Poly(benzyl methacrylate) has very interesting properties, yet its synthesis via NMP is challenging. Random copolymerization of benzyl methacrylate and styrene with various compositions showed promising results. Results and observations regarding kinetics, MWD, copolymer “livingness” and monomer reactivity ratios are reported.

The morphology of composite latex particles evolves with time during the reaction. When the second-stage polymer is glassy at reaction temperature, the phase structure of the particles can evolve in very interesting ways. This can lead to kinetically frozen mixtures as well as a pure component shell. Computational models can provide insight as to how and when such structure development occurs.

BA/MMA (90:10 wt.-%) were copolymerized in miniemulsion in the presence of two different organomodified clays (C30B and CMA16), and particle morphologies were compared with a Monte-Carlo simulation. C30B and CMA16 did not meet the simulated requirements for encapsulated morphologies, and provided a preferential surface location of the platelets on the polymer/water interphase as predicted by the model (Δ_clay/monomer = 0.3–0.6, Δ_clay/water = 0.6).

Polymeric porous membranes with a high control of pore size and morphology were fabricated from templates made from silica particles. The pre-specified pore morphology makes these membranes of special interest in sensors, separation and water treatment process given their three-dimensional periodic structures and high specific surface areas.

The synthesis and curing of “bioinspired” copolymers based on vinylbenzyl thymine (VBT) and ionically charged vinylbenzyl triethylammonium chloride (VBA) monomers are studied. The environmentally benign, non-toxic and recyclable polymers obtained can be used as substitutes for traditional materials in photo-resist technologies.