The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform
Anthony Ledwith - One of the best experts on this subject based on the ideXlab platform.
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Photoinitiated cationic Polymerization of epoxide and vinyl monomers by p-trimethoxytrityl salts
Journal of Polymer Research, 2007Co-Authors: Ideisan I. Abu-abdoun, Anthony LedwithAbstract:Photoinitiated cationic Polymerizations of cyclohexene oxide, tetrahydrofuran and N -vinylcarbazole were investigated in dichloromethane at 25°C, using stable, soluble and nonhygroscopic p -trimethoxytrityl salts having nonnucleophilic Anions such as SbF_6 ^−, AsF_6 ^−, PF_6 ^−, BF_4 ^−, and SbCl_6 ^−. The effects of Anion, Polymerization time, concentration of the salt and the intensity of light on the Polymerization reaction are presented.
Jesús Sanz - One of the best experts on this subject based on the ideXlab platform.
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Effect of the SiO2/Na2O ratio on the alkali activation of fly ash. Part II: 29Si MAS-NMR Survey
Microporous and Mesoporous Materials, 2020Co-Authors: Maria Criado, Ana Fernández-jiménez, Ángel Palomo, Isabel Sobrados, Jesús SanzAbstract:Si MAS-NMR spectroscopy was used to characterize the reaction products resulting from the alkali activation of a type F fly ash. Specifically, analyses focused on the degree of Polymerization of the activating solution (SiO2/Na2O ratio = 0.0, 0.19, 0.69 and 1.17) and thermal curing time (from 8 h to 180 days at 85 °C). The results obtained showed that the degree of Polymerization of the predominant silica species in the activation solutions plays an important role in the kinetics, structure and composition of the gel initially formed. The alkaline aluminosilicate gel formed exhibits short-range order, with the silicon appearing in a wide variety of Q4(nAl) (n = 0, 1, 2, 3 and 4) environments. In the absence of soluble silica (SiO2/Na2O ratio = 0.0, 0.19), the Al-rich gels initially generated evolved rapidly into zeolites. At higher levels of Anion Polymerization (SiO2/Na2O ratio 0.5), zeolite crystallization was retarded.Funding for this research was provided by the Directorate General of Scientific Research under project BIA2004-04835; a post-doctoral contract associated with the study was awarded by the CSIC and co-financed by the European social fund (REF. I3P-PC2004L).Peer reviewe
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Effect of the SiO2/Na2O ratio on the alkali activation of fly ash. Part II: 29Si MAS-NMR Survey
Microporous and Mesoporous Materials, 2008Co-Authors: Maria Criado, Ana Fernández-jiménez, Ángel Palomo, Isabel Sobrados, Jesús SanzAbstract:Abstract 29 Si MAS-NMR spectroscopy was used to characterize the reaction products resulting from the alkali activation of a type F fly ash. Specifically, analyses focused on the degree of Polymerization of the activating solution (SiO 2 /Na 2 O ratio = 0.0, 0.19, 0.69 and 1.17) and thermal curing time (from 8 h to 180 days at 85 °C). The results obtained showed that the degree of Polymerization of the predominant silica species in the activation solutions plays an important role in the kinetics, structure and composition of the gel initially formed. The alkaline aluminosilicate gel formed exhibits short-range order, with the silicon appearing in a wide variety of Q 4 ( n Al) ( n = 0, 1, 2, 3 and 4) environments. In the absence of soluble silica (SiO 2 /Na 2 O ratio = 0.0, 0.19), the Al-rich gels initially generated evolved rapidly into zeolites. At higher levels of Anion Polymerization (SiO 2 /Na 2 O ratio ⩾0.5), zeolite crystallization was retarded.
Jianwen Yang - One of the best experts on this subject based on the ideXlab platform.
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Benzoylformamides as versatile photocaged bases for redox free radical photoPolymerization
Photochemical and Photobiological Sciences, 2016Co-Authors: Ruixin Xu, Minghui He, Jianwen YangAbstract:Benzoylformamides (BFAs) are proposed as photocaged bases for redox free radical photoPolymerization (FRP). Initially the dissolving capacity of BFAs was evaluated. Besides our previously reported photo-latent Anion Polymerization, BFAs, as versatile photocaged bases, can not only initiate the FRP of acrylates unassisted, but also perform redox FRP in combination with a benzoyl peroxide initiator. We detail a model photoPolymerization in the presence of BFA-dBA (N,N-dibenzyl-2-oxo-2-phenylacetamide) as the photocaged base. In combination with a benzoyl peroxide initiator, BFAs are able to initiate the amine-mediated redox photoPolymerization of acrylates, and enhance the photoPolymerization rate. Finally, we investigated the mechanism of the radical formation to initiate the redox FRP, as exemplified by BFA-dBA.
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benzoylformamides as new photocaged bases for photo latent Anion Polymerization
Chinese Chemical Letters, 2015Co-Authors: Minghui He, Meilin Su, Zhaohui Yu, Guangxue Chen, Zhaohua Zeng, Jianwen YangAbstract:Abstract Benzoylformamide (BFA) derivatives are proposed as new photocaged bases with good solubility in epoxy resin. Initially their structures were confirmed by 1 H NMR, 13 C NMR, and elemental analysis. Next, we detail their thermal stability, solubility behavior, and photolysis products. Furthermore, the model photo-latent Anion Polymerization (AP) of epoxide system in the presence of BFA-dBA ( N , N -dibenzyl-2-oxo-2-phenylacetamide) as a photocaged base has been investigated, and excellent photoPolymerization profile is obtained.
Feng Xiu-e - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of poly(methacrylic acid)-b-polystyrene-b-poly (methacrylic acid)
China Surfactant Detergent & Cosmetics, 2020Co-Authors: Feng Xiu-eAbstract:The block copolymer poly(tert-butyl methacrylate)-b-polystyrene-b-poly(tert-butyl methacrylate)(PTBMA-PS-PTBMA)was synthesized by bidirectional Anion Polymerization using sodium naphthalene as reagent initiator.The ABA type amphiphilic block copolymer poly(methacrylic acid)-b-polystyrene-b-poly(methacrylic acid)(PMAA-PS-PMAA)was prepared successfully through hydrolysis of PTBMA-PS-PTBMA under alkaline condition.The products were characterized by FTIR,TG and GPC.When the mass ratio of styrene and tert-butyl methacrylate is 54∶46,the proportion of corresponding copolymer blocks is about 79∶21.
Feng Zhou - One of the best experts on this subject based on the ideXlab platform.
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Preparation and mechanism of polystyrene-molybdenum disulfide intercalation materials by a modified two-step route
Materials Research Innovations, 2003Co-Authors: Tingmei Wang, Jun Tian, Laigui Yu, Feng ZhouAbstract:Polystyrene/molybdenum disulfide nanocomposites were prepared by means of a modified two-step in-situ Anion Polymerization of the intercalated styrene monomers. The nanocomposites were characterized by means of powder X-ray diffraction, Fourier transform infrared spectroscopy, gel permeation chromatography, and scanning electron microscopy. Thus, the target nanocomposites were prepared at a greatly reduced reaction time using the modified synthetic route. This was characterized by a clean and straightforward intercalation of the interesting polymer monomers into the molybdenum disulfide host. The mechanism of the intercalation method was investigated and compared with the traditional exfoliation-restacked method as well.
