Roger Fayt

Bio: Roger Fayt is an academic researcher from University of Liège. The author has contributed to research in topics: Copolymer & Anionic addition polymerization. The author has an hindex of 26, co-authored 73 publications receiving 2503 citations. Previous affiliations of Roger Fayt include Solvay.

Anionic polymerization of (meth)acrylic monomers. 4. Effect of lithium salts as ligands on the "living" polymerization of methyl methacrylate using monofunctional initiators

Abstract: The low-temperature polymerization of methyl methacrylate initiated with monofunctional lithium carbanionic species is studied in THF and in a 9:1 toluene-THF mixture. Lithium chloride, although not influencing the stereochemistry of the propagation, has an important beneficial effect on the «living» character of the process, allowing the high-yield synthesis of PMMA samples displaying a predetermined molecular weight and a very low polydispersity. The LiCl:initiator molar ratio and the polarity of the solvent have been shown to be determinant parameters in the association equilibrium involved in these controls

New initiator system for the "living" anionic polymerization of tert-alkyl acrylates

Abstract: Polymerisation de l'acrylate de butyle dans le THF ou le melange THF/toluene, a −78°C, avec un amorceur RLi prepare par reaction du sec-BuLi avec un exces d'α-methylstyrene

Molecular design of multicomponent polymer systems. XIV. Control of the mechanical properties of polyethylene–polystyrene blends by block copolymers

Abstract: Amelioration notable de la resistance a la traction et de l'allongement a la rupture d'alliages de polystyrene et de polyethylenes differents par addition de 2 a 10% de copolymeres de styrene et de butadiene hydrogene. Etude de l'amelioration en fonction de la structure des copolymeres: copolymeres bisequences plus efficaces. Importance du processus de melange a l'etat fondu et interet de l'addition d'emulsifiants polymeres

Molecular design of multicomponent polymer systems, 13. Control of the morphology of polyethylene/polystyrene blends by block copolymers

Abstract: As investigated by optical and electron microscopy, the observed morphology of the meltblended polyethylene/polystyrene pair unambiguously supports the interfacial activity of poly(hydrogenated butadiene-b-styrene) copolymers. The phase size is significantly reduced, the interfacial adhesion is dramatically increased and the phase dispersion is firmly stabilized against coalescence during subsequent processing. Diblock copolymers with a balanced composition are the most efficient interfacial agents in such an extent that only small amounts (1–2 wt.-%) are required to obtain homogeneous and stable phase dispersions. The emulsification concept applied to melt-blended immiscible polymers appears to be a powerful technique to prepare valuable polymer alloys.

Molecular design of multicomponent polymer systems. III. Comparative behavior of pure and tapered block copolymers in emulsification of blends of low‐density polyethylene and polystyrene

Abstract: Poly(hydrogenated butadiene-b-styrene) copolymers are very effective emulsifiers for blends of polystyrene and low-density or high-density polyethylene. It is shown that the extent of improvement in mechanical properties is dependent not only on the molecular weight but also on the structure of the diblock copolymer. A comparative study of the morphology and the mechanical behavior of modified low-density polyethylene/polystyrene blends demonstrates that a tapered diblock is more efficient than a pure diblock with the same composition and molecular weight. It is assumed that the unique behavior of the tapered sample results from its particular miscibility characteristics at the blend interface. The tapered copolymer could behave essentially as a solu-bilizing agent for the homopolymers at the interface and provide a “graded” modulus responsible for the improved mechanical response of the material.

Living Polymerization Methods

Abstract: Living polymerization techniques can be used to achieve a high degree of control over polymer chain architecture. Examples of the type of polymers that can be synthesized include block copolymers, comb-shaped polymers, multiarmed polymers, ladder polymers, and cyclic polymers. This control of structure, in turn, results in polymers with widely diverse physical properties, even though they are made from readily available low-cost monomers.

Anionic polymerization: High vacuum techniques

Abstract: Anionic polymerization is a powerful tool for the synthesis of a variety of model materials with well-defined molecular characteristics. However specially designed apparatuses and appropriate high vacuum techniques are needed in order to exclude from the reaction environment all reactive contaminants with the anionic centers. This review describes the basic principles of anionic polymerization as well as detailed experimental methods for the purification of the reagents usually used for the synthesis of model polymeric materials. In addition a few examples of the synthesis of polymers with complex architecture are given. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3211–3234, 2000

Coordination polymerization of polar vinyl monomers by single-site metal catalysts.

Abstract: 1.3. Scope of Review 5161 2. Methacrylate Polymerization 5161 2.1. Lanthanide Complexes 5161 2.1.1. Nonbridged Lanthanocenes 5161 2.1.2. ansa-Lanthanocenes 5164 2.1.3. Half-Lanthanocenes 5166 2.1.4. Non-lanthanocenes 5166 2.2. Group 4 Metallocenes 5170 2.2.1. Nonbridged Catalysts 5170 2.2.2. ansa-C2v-Ligated Catalysts 5173 2.2.3. ansa-C2-Ligated Catalysts 5173 2.2.4. ansa-C1-Ligated Catalysts 5176 2.2.5. ansa-Cs-Ligated Catalysts 5177 2.2.6. Constrained Geometry Catalysts 5178 2.2.7. Half-Metallocene Catalysts 5180 2.2.8. Supported Catalysts 5180 2.3. Other Metallocene Catalysts 5180 2.4. Nonmetallocene Catalysts 5181 2.4.1. Group 1 and 2 Catalysts 5181 2.4.2. Group 13 Catalysts 5183 2.4.3. Group 14 Catalysts 5186 2.4.4. Transition-Metal Catalysts 5187 3. Acrylate Polymerization 5188 3.1. Lanthanocenes 5188 3.2. Group 4 Metallocenes 5189 3.3. Nonmetallocenes 5190 4. Acrylamide and Methacrylamide Polymerization 5191 4.1. Acrylamides 5191 4.2. Methacrylamides 5192 4.3. Asymmetric Polymerization 5193 5. Acrylonitrile and Vinyl Ketone Polymerization 5196 5.1. Acrylonitrile 5196 5.2. Vinyl Ketones 5196 6. Copolymerization 5197 6.1. Polar-Nonpolar Block Copolymers 5197 6.2. Polar-Nonpolar Random Copolymers 5199 6.3. Polar-Polar Copolymers 5204 7. Ion-Pairing Polymerization 5206 8. Summary and Outlook 5208 9. Acknowledgments 5208 10. References 5208