Functional polymers by atom transfer radical polymerization

A more versatile route to block copolymers and other polymers of complex architecture by living radical polymerization : The RAFT process

Advances in RAFT polymerization: the synthesis of polymers with defined end-groups

Self-healing of covalently cross-linked polymers under an ambient visible light in the bulk state, in air, at room temperature using radical exchange of thiuram disulfide units is reported. The successful attachment of surfaces of cut pieces proceeded under ambient conditions under exposure to visible light from a commercial tabletop lamp, as confirmed by bending and tensile tests.

Self‐Healing of Covalently Cross‐Linked Polymers by Reshuffling Thiuram Disulfide Moieties in Air under Visible Light

A novel class of homogeneous nickel(II) catalysts, i.e [Ni{o,o‘(CH2NMe2)2C6H3}Br], denoted as Ni(NCN‘)Br, is reported to mediate in the presence of activated alkyl halides, e.g., CCl4 or α-halocarbonyl compounds, a well-controlled radical polymerization of methacrylic monomers [methyl and n-butyl methacrylate), (MMA, n-BuMA)] at rather low temperatures (<100 °C). The number-average molecular weight of the polymer gradually increased with the monomer conversion and was inversely proportional to the initiator concentration of alkyl halides. The molecular weight distribution (MWD) remained very narrow during the whole course of the polymerization (MWD < 1.3). All the experimental data including a successful block copolymerization (n-BuMA-b-MMA) experiment were in agreement with a living polymerization process, and remarkably enough, poly(methyl methacrylate) (PMMA) with molecular weight up to at least 105 g/mol was synthesized in a controlled fashion. Increased thermal stability of the PMMA is a further indi...

Controlled Radical Polymerization of Methacrylic Monomers in the Presence of a Bis(ortho-chelated) Arylnickel(II) Complex and Different Activated Alkyl Halides

Flame and thermal resistance of phosphorus-functionalized poly(methyl methacrylate) and polystyrene

Soluble copolymers of diethyl 2-(methacryloyloxy) ethyl phosphate (DMP) with methyl methacrylate (MMA), methyl acrylate (MA), ethyl acrylate (EA) and butyl acrylate (BA) were synthesized by radical copolymerization in benzene solution using azobis(isobutyronitrile) (AIBN) as initiator. The monomer reactivity ratios of these systems at 60°C were determined by the conventional schemes using the methods of Fineman–Ross, Joshi-Joshi, and Kelen–Tudos. DMP underwent a completely random and azeotropic copolymerization with MMA whereas in its reaction with the other acrylates DMP entered preferentially into the polymer chain. The reactivities of DMP-terminated polymer radicals towards the acrylate monomers were found to be in the order: MMA > EA > MA > BA. An increase in solvent polarity decreased the relative reactivity of DMP for the DMP-MMA pair. An examination of the molecular weights of the copolymers revealed the occurrence of chain transfer caused by DMP. The copolymer glass transition temperatures were determined and the variations of Tg with copolymer compositions were discussed according to the theory of Johnston, taking into account the effect of the sequence distributions of the comonomers on Tg. The Tgs of the alternating copolymers of DMP with the four alkyl acrylates were calculated.

Copolymerization of diethyl 2‐(methacryloyloxy) ethyl phosphate with alkyl acrylates: Reactivity ratios and glass transition temperatures

α,ω-Dihydroxy-terminated-PMMA was synthesized by the bulk polymerization of methyl methacrylate in the presence of a functional “iniferter,” viz., N,N′-diethyl-N,N′-bis(2-hydroxyethyl)thiuram disulfide (DHTD). The kinetics of the polymerization were studied by determining the polymerization rate as a function of the “iniferter” concentration at 60, 70, 85, and 95°C. Evaluation of the data by a computerized multiple regression analysis led to calculation of the various kinetic parameters and the activation energies of the related phenomena. The maximum observed in the Rp–initiator concentration curve was found to shift to lower initiator concentration as the temperature increased. The formal reaction order with respect to the concentration of the initiator decreased with increasing temperature and concentration of DHTD. The chain transfer constants of DHTD with MMA were calculated from the molecular weights of the resulting polymers. The functionalities of the oligomers were calculated from the elemental analysis of the chain end groups. Thermogravimetric analysis revealed that the polymer chain ends were devoid of unsaturated groups and that the polymer underwent degradation only by random scission.

Functionalization of PMMA by a functional “iniferter”: Kinetics of polymerization of MMA using N,N′-diethyl-N,N′-bis(2-hydroxyethyl) thiuram disulfide

Preparation de poly(dimethylsiloxane) iniFerters comportant des groupes disulfure de thiuranne dans la chaine. Caracterisation des iniFerters par viscosimetrie IR et DSC et etude de leur cinetique de dissociation. Preparation de copolymeres sequences par reaction des iniFerters avec le styrene, l'acrylamide, le methacrylate de methyle. Les copolymeres avec l'acrylamide sont amphiphiles

Block copolymers via thermal polymeric iniferters. Synthesis of silicone-vinyl block copolymers

A thorough understanding of the structure physical/mechanical properties of the polymers has made possible the molecular design of macromolecules for specific application needs. Several methods exist for polymer synthesis and processing. When it concerns homopolymers, each polymer structure is identified with a particular method for its realization. Depending upon the situation, one or more of the methods (polycondensation, cationic, anionic, or free radical technique) is sometimes resorted to. Each process has its own merits and demerits. The condensation method is applicable to only a few cases of condensation monomers. A variety of vinyl and cyclic monomers are polymerized by anionic and cationic processes. These processes have obvious disadvantages in the sense that they warrant rigorous polymerization conditions like the need for ultrapure monomers, absolute moisture/oxygen free atmosphere, and cryogenic temperatures which are often difficult to realize on an industrial scale. A recent trend...

G. Clouet

Papers

Flame and thermal resistance of phosphorus-functionalized poly(methyl methacrylate) and polystyrene

Copolymerization of diethyl 2‐(methacryloyloxy) ethyl phosphate with alkyl acrylates: Reactivity ratios and glass transition temperatures

Functionalization of PMMA by a functional “iniferter”: Kinetics of polymerization of MMA using N,N′-diethyl-N,N′-bis(2-hydroxyethyl) thiuram disulfide

Block copolymers via thermal polymeric iniferters. Synthesis of silicone-vinyl block copolymers

Thermal iniferters: their concept and application in free radical polymerization