Search results for "Radical polymerization"
showing 10 items of 184 documents
Vinyl ferrocenyl glycidyl ether: an unprotected orthogonal ferrocene monomer for anionic and radical polymerization
2015
The first orthogonal ferrocene monomer, vinyl ferrocenyl glycidyl ether (VfcGE), for both anionic and radical polymerization – without the need of a protection group – is presented. Anionic ring-opening copolymerization of VfcGE and ethylene oxide (EO) generates stimuli-responsive, multifunctional poly[(vinyl ferrocenyl glycidyl ether)-co-(ethylene oxide)] (P[VfcGE-co-EO]) copolymers (molecular weights of ca. 7500 g mol−1 and low molecular weight dispersities (Đ ≤ 1.14)). The amount of the equimolar ferrocenyl and vinyl groups are controlled by the comonomer ratio up to 15.4 mol% VfcGE. The pendant vinyl groups of P[VfcGE-co-EO] were post-modified with 3-mercaptopropionic acid via thiol–ene…
Maleimide Glycidyl Ether: A Bifunctional Monomer for Orthogonal Cationic and Radical Polymerizations.
2015
A novel bifunctional monomer, namely maleimide glycidyl ether (MalGE), prepared in a four-step reaction sequence is introduced. This monomer allows for selective (co)polymerization of the epoxide group via cationic ring-opening polymerization, preserving the maleimide functionality. On the other hand, the maleimide functionality can be copolymerized via radical techniques, preserving the epoxide moiety. Cationic ring-opening multibranching copolymerization of MalGE with glycidol was performed, and a MalGE content of up to 24 mol% could be incorporated into the hyperbranched polymer backbone (Mn = 1000-3000 g mol(-1)). Preservation of the maleimide functionality during cationic copolymerizat…
Polymerizable ring-shaped molecules containing aspartic acid: synthesis and free radical polymerization of a macrocycle derived from (N'-methacryloyl…
1999
A novel polymerizable macrocycle, 6, was prepared using high dilution techniques. Starting from N-(N'-methacryloyl-11-aminoundecanoyl)-L-aspartic acid dimethyl ester (2), N-(N'methacryloyl-11-aminoundecanoyl)-α,β-bis( 4,9-dioxadodecane-1,12-diamine)-L-aspartic acid amide (4) was obtained via amino-lysis with the bifunctional amine 4,9-dioxadodecane-1,12-diamine (3) in high excess. Addition of the free amino groups to toluene-2,4-diisocyanate (5) under high dilution provided macrocycle 6. The existence and purity of 6 were confirmed by mass spectrometry, NMR and IR spectroscopy, and HPLC. The methacrylic function was used to build up oligomers by free radical polymerization, using AIBN as an…
Lanthanides benzimidinates: initiators or real catalysts for theɛ-caprolactone polymerization
2000
Sequential conversion of orthogonally functionalized diblock copolymers based on pentafluorophenyl esters
2010
Statistic and block copolymers exhibiting activated ester side groups were synthesized by reversible addition-fragmentation chain transfer polymerization in the presence of cumyl dithiobenzoate, benzyl dithiobenzoate, and 4-cyano-4-((thiobenzoyl)sulfanyl)pentanoic acid as chain transfer agents. Pentafluorophenyl methacrylate and pentafluorophenyl 4-vinylbenzoate were used to enable a sequential functionalization of the obtained copolymers by conversion of the activated esters with different amines. 1H NMR spectroscopy, 19F NMR spectroscopy, and FTIR spectroscopy showed the successful step-by-step conversion of the different activated esters by aniline followed by aliphatic amines, thereby r…
Poly(Ethylene Glycol) Dimethacrylates with Cleavable Ketal Sites: Precursors for Cleavable PEG-Hydrogels.
2017
The authors introduce poly(ethylene glycol) (PEG) based macromonomers containing acid-labile ketal moieties as well as terminal methacrylate units that are amenable to radical polymerization. The synthesis of PEGs of different molecular weights (ranging from 2000 to 13 000 g mol-1 with polydispersities <1.15) with a central ketal unit (PEG-ketal-diol) and their conversion to PEG-ketal-dimethacrylates (PEG-ketal-DMA) is introduced. Degradation rates of both PEG-ketal-diols and PEG-ketal-DMA are investigated by in situ 1 H NMR kinetic studies in deuterated phosphate buffer. Hydrogels containing 0, 5, or 10 wt% of PEG-ketal-DMA and 100, 95, or 90 wt% of PEG-DMA, respectively, are synthesized a…
Peculiar behavior of degenerative chain transfer polymerization of a phosphonated methacrylate
2009
Living/controlled radical polymerization of dimethyl(methacryloyloxy)methyl phosphonate (MAPC) has been attempted using degenerative transfer to produce block copolymers. RAFT polymerization of this monomer is sensitive to very low level of oxygen and in any case limited to low monomer conversion. Reverse iodine transfer polymerization (RITP) leads to higher monomer conversion with a limited amount of living polymer (55% by H NMR), precluding an efficient synthesis of block copolymers. A PMMA-b-PMAPC diblock copolymer was therefore synthesized by iodine transfer polymerization (ITP) of MAPC from a PMMA-Imacro-chain transfer agent prepared by RITP. The diblock copolymer, purified by selectiv…
An Experimental and Computational Study on the Effect of Al(OiPr)3 on Atom-Transfer Radical Polymerization and on the Catalyst-Dormant Chain Halogen …
2005
International audience; Compound Al(OiPr)3 is shown to catalyze the halide-exchange process leading from [Mo(Cp)Cl2(iPrN=CH-CH=NiPr)] and CH3CH(X)COOEt (X=Br, I) to the mixed-halide complexes [Mo(Cp)ClX(iPrN=CH-CH=NiPr)]. On the other hand, no significant acceleration is observed for the related exchange between [MoX3(PMe3)3] (X=Cl, I) and PhCH(Br)CH3, by analogy to a previous report dealing with the RuII complex [RuCl2(PPh3)3]. A DFT computation study, carried out on the model complexes [Mo(Cp)Cl2(PH3)2], [MoCl3(PH3)3], and [RuCl2(PH3)3], and on the model initiators CH3CH(Cl)COOCH3, CH3Cl, and CH3Br, reveals that the 16-electron RuII complex is able to coordinate the organic halide RX in a…
Radikalpolymerisation von methylmethacrylat im gesamten umsatzbereich. Stationäre und instationäre experimente zur bestimmung von wachstums- und abbr…
1989
Free-radical polymerization of methyl methacrylate in bulk at 0°C over the full range of conversion is reported. Details for stationary and non-stationary experiments are described allowing to measure both kinetically relevant ratios fk/ka and kw/ka, f representing radical efficiency, kw rate constants of propagation and ka rate constant of termination. From these ratios the absolute rate constants kw and ka are available. The photochemical decay of the initiator 1,1′-azodicyclohexanenitrile in connection with the rotating-sector technique and observation of the post-effect after stopping the initiator decay were used. The rate of polymerization and the number- and weight-average molar mass…