The polymerization of methyl methacrylate (MMA) initiated by organic peroxide and polymerizable aromatic tertiary amine such as N, N-di (2-α-methylacryloyloxy propyl)-p-toluidine (MP)_2PT binary system has been studi...The polymerization of methyl methacrylate (MMA) initiated by organic peroxide and polymerizable aromatic tertiary amine such as N, N-di (2-α-methylacryloyloxy propyl)-p-toluidine (MP)_2PT binary system has been studied. It was found that the (MP)_2PT promotes MMA polymerization, and the kinetics of MMA polymerization fits the radical polymerization rate equation. Based on the ESR studies and the end-group analysis the initiation mechanism is proposed.展开更多
The initiation mechanism of methyl methacrylate (MMA) polymerization by organic peroxide and polymerizable aromatic tertiary amine such as N-methacryloyloxyethyl-N-methyl aniline (MEMA) binary system has been studied....The initiation mechanism of methyl methacrylate (MMA) polymerization by organic peroxide and polymerizable aromatic tertiary amine such as N-methacryloyloxyethyl-N-methyl aniline (MEMA) binary system has been studied. The kinetics of polymerization of MMA and the ESR spectra of organic peroxide/MEMA system were determined. Based on the ESR study and the end-group analysis by UV spectra of the polymer formed, the initiation mechanism is proposed.展开更多
Acrylamide polymerization initiated with a redox initiation system consisting of eerie ion and ethyl N,N-diethyldithiocarbamyl acetate (EDCA) has been studied. It was found that the polymerization rate equation is in ...Acrylamide polymerization initiated with a redox initiation system consisting of eerie ion and ethyl N,N-diethyldithiocarbamyl acetate (EDCA) has been studied. It was found that the polymerization rate equation is in good agreement with that of a redox initiated polymerization, and the overall activation energy of the polymerization was determined to be 25.2 kJ.mol(-1). Accordingly, the system belongs to a redox initiator. The initiation mechanism was proposed based on the end group analysis using FT-IR, UV spectroscopies. Analysis results revealed that the N, N-diethyldithiocarbamyl radical produced from the redox reaction of EDCA with eerie ion can initiate acrylonitrile (AN) polymerization and form the end group on PAN. The resulting PAN was photopolymerized with butyl acrylate (BE) to form PAN-b-PBA block copolymer.展开更多
The graft copolymerization of 4-vinyl pyridine (4VP) onto nylon-6 (PA6) was studied by using potassium diperiodatonickelate(IV) (DPN)-PA6 redox system in alkaline medium. The structures of graft copolymers wer...The graft copolymerization of 4-vinyl pyridine (4VP) onto nylon-6 (PA6) was studied by using potassium diperiodatonickelate(IV) (DPN)-PA6 redox system in alkaline medium. The structures of graft copolymers were confirmed by Fourier transfer infrared spectroscopy (FTIR) and X-ray diffraction. The properties of graft copolymers were investigated by thermogravimetric analysis (TGA). A mechanism was proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, the ratio of 4VP to PA6, pH as well as reaction temperature and time were investigated. Graft copolymers with high grafting efficiency (〉95%) were obtained, which indicated that DPN-PA6 redox system is an efficient initiator for this graft copolymerization. The quaternized PA6-g-P4VP (QPAVP) was proved to be an excellent adsorbent to heavy metal ions.展开更多
The homopolymerization of 5-methyl-5-hexen-2,4-dione (methacryloylacetone, MAA), a vinyl monomer having beta-diketone group, was carried out in the presence of benzophenone (BP)/N, N-dimenthyl-4-toluidine (DMT) system...The homopolymerization of 5-methyl-5-hexen-2,4-dione (methacryloylacetone, MAA), a vinyl monomer having beta-diketone group, was carried out in the presence of benzophenone (BP)/N, N-dimenthyl-4-toluidine (DMT) system. Graft polymerization of acrylamide initiated by eerie ion onto the homopolymer film was investigated and the mechanism of the grafting reaction was proposed on the basis of ESR study. The grafted copolymer was characterized by means of grafting percentage, water absorption, XPS spectra and scanning electron photomicrographs.展开更多
Thioxanthone-based N-phthalimidoamino acid ammonium salt(thioxanthen-DBU) as a photocaged base was synthesized and characterized. The photochemical properties and initiation mechanism were analyzed. It was found tha...Thioxanthone-based N-phthalimidoamino acid ammonium salt(thioxanthen-DBU) as a photocaged base was synthesized and characterized. The photochemical properties and initiation mechanism were analyzed. It was found that the compound absorbs over the UV and visible region with relatively high absorption coefficients. Furthermore, the covalent binding of N-phthalimidoamino acid and type II chromophores(thioxanthone, TX) remarkably improved the photoreactivity. Specifically, in combination with a benzoyl peroxide initiator, thioxanthen-DBU was able to initiate the amine-mediated redox photopolymerization of trimethylol propane triacrylate(TMPTA), and an excellent photopolymerization profile was obtained.展开更多
Since tertiary amines (Cα-H) can be oxidized by peroxides and transition metal cations in high oxidation states into Ca2+ radicals to initiate vinylic polymerizations of methacrylates, Cu2+ and 2-(N,N-dimethylam...Since tertiary amines (Cα-H) can be oxidized by peroxides and transition metal cations in high oxidation states into Ca2+ radicals to initiate vinylic polymerizations of methacrylates, Cu2+ and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) form a polymerizable redox initiating pair, in which DMAEMA serves as an intrinsically reducing inimer. CuSOa-catalyzed aqueous self-initiated radical polymerizations of DMAEMA were successfully performed at ambient temperature via a continuous Cu2+-tertiary amine redox initiation based on catalyst regeneration in the presence of O2. The polymerization kinetics was monitored by gas chromatography and the structure of PDMAEMA was characterized by gel- permeation chromatography, nuclear magnetic resonance spectroscopy, laser light scattering and online intrinsic-viscosity analysis. Both the monomer conversion and the molecular weight of PDMAEMA increase with the reaction while the molecular weight distribution maintains rather broad, as the Cu2+-DMAEMA redox-initiation leads to linear PDMAEMA chains with terminal methacryloxyl moieties, and the Cu2+-PDMAEMA redox-initiation results in branched chains. The branched topology forms and develops only for the high-MW components of the PDMAEMA. Our results provide a facile strategy to prepare branched polymers from such commercially available intrinsically reducing inimers using a negligible concentration of regenerative air-stable catalysts.展开更多
文摘The polymerization of methyl methacrylate (MMA) initiated by organic peroxide and polymerizable aromatic tertiary amine such as N, N-di (2-α-methylacryloyloxy propyl)-p-toluidine (MP)_2PT binary system has been studied. It was found that the (MP)_2PT promotes MMA polymerization, and the kinetics of MMA polymerization fits the radical polymerization rate equation. Based on the ESR studies and the end-group analysis the initiation mechanism is proposed.
基金Project supported by the National Natural Science Foundation of China
文摘The initiation mechanism of methyl methacrylate (MMA) polymerization by organic peroxide and polymerizable aromatic tertiary amine such as N-methacryloyloxyethyl-N-methyl aniline (MEMA) binary system has been studied. The kinetics of polymerization of MMA and the ESR spectra of organic peroxide/MEMA system were determined. Based on the ESR study and the end-group analysis by UV spectra of the polymer formed, the initiation mechanism is proposed.
基金The Project 29234093 was supported by the National Natural Science Foundation of China.
文摘Acrylamide polymerization initiated with a redox initiation system consisting of eerie ion and ethyl N,N-diethyldithiocarbamyl acetate (EDCA) has been studied. It was found that the polymerization rate equation is in good agreement with that of a redox initiated polymerization, and the overall activation energy of the polymerization was determined to be 25.2 kJ.mol(-1). Accordingly, the system belongs to a redox initiator. The initiation mechanism was proposed based on the end group analysis using FT-IR, UV spectroscopies. Analysis results revealed that the N, N-diethyldithiocarbamyl radical produced from the redox reaction of EDCA with eerie ion can initiate acrylonitrile (AN) polymerization and form the end group on PAN. The resulting PAN was photopolymerized with butyl acrylate (BE) to form PAN-b-PBA block copolymer.
文摘The graft copolymerization of 4-vinyl pyridine (4VP) onto nylon-6 (PA6) was studied by using potassium diperiodatonickelate(IV) (DPN)-PA6 redox system in alkaline medium. The structures of graft copolymers were confirmed by Fourier transfer infrared spectroscopy (FTIR) and X-ray diffraction. The properties of graft copolymers were investigated by thermogravimetric analysis (TGA). A mechanism was proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, the ratio of 4VP to PA6, pH as well as reaction temperature and time were investigated. Graft copolymers with high grafting efficiency (〉95%) were obtained, which indicated that DPN-PA6 redox system is an efficient initiator for this graft copolymerization. The quaternized PA6-g-P4VP (QPAVP) was proved to be an excellent adsorbent to heavy metal ions.
基金The project was supported by the National Natural Science Foundation of Chna.
文摘The homopolymerization of 5-methyl-5-hexen-2,4-dione (methacryloylacetone, MAA), a vinyl monomer having beta-diketone group, was carried out in the presence of benzophenone (BP)/N, N-dimenthyl-4-toluidine (DMT) system. Graft polymerization of acrylamide initiated by eerie ion onto the homopolymer film was investigated and the mechanism of the grafting reaction was proposed on the basis of ESR study. The grafted copolymer was characterized by means of grafting percentage, water absorption, XPS spectra and scanning electron photomicrographs.
基金financially supported by National Natural Science Foundation of China(No.20974127,21374135)China Postdoctoral Science Foundation(No.2013M542178)+1 种基金the Open Foundation of the State Key Laboratory of Pulp and Paper Engineering in South China University of Technology(No.C713043z)the Fundamental Research Funds for the Central Universities(No.2013ZB0025)
文摘Thioxanthone-based N-phthalimidoamino acid ammonium salt(thioxanthen-DBU) as a photocaged base was synthesized and characterized. The photochemical properties and initiation mechanism were analyzed. It was found that the compound absorbs over the UV and visible region with relatively high absorption coefficients. Furthermore, the covalent binding of N-phthalimidoamino acid and type II chromophores(thioxanthone, TX) remarkably improved the photoreactivity. Specifically, in combination with a benzoyl peroxide initiator, thioxanthen-DBU was able to initiate the amine-mediated redox photopolymerization of trimethylol propane triacrylate(TMPTA), and an excellent photopolymerization profile was obtained.
基金financially supported by the National Natural Science Foundation of China(No.20674033)Natural Science Foundation of Jiangsu Province(No.BK2008142)Scientific Research Foundation for the Returned Overseas Chinese Scholars(State Education Ministry)
文摘Since tertiary amines (Cα-H) can be oxidized by peroxides and transition metal cations in high oxidation states into Ca2+ radicals to initiate vinylic polymerizations of methacrylates, Cu2+ and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) form a polymerizable redox initiating pair, in which DMAEMA serves as an intrinsically reducing inimer. CuSOa-catalyzed aqueous self-initiated radical polymerizations of DMAEMA were successfully performed at ambient temperature via a continuous Cu2+-tertiary amine redox initiation based on catalyst regeneration in the presence of O2. The polymerization kinetics was monitored by gas chromatography and the structure of PDMAEMA was characterized by gel- permeation chromatography, nuclear magnetic resonance spectroscopy, laser light scattering and online intrinsic-viscosity analysis. Both the monomer conversion and the molecular weight of PDMAEMA increase with the reaction while the molecular weight distribution maintains rather broad, as the Cu2+-DMAEMA redox-initiation leads to linear PDMAEMA chains with terminal methacryloxyl moieties, and the Cu2+-PDMAEMA redox-initiation results in branched chains. The branched topology forms and develops only for the high-MW components of the PDMAEMA. Our results provide a facile strategy to prepare branched polymers from such commercially available intrinsically reducing inimers using a negligible concentration of regenerative air-stable catalysts.