The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
David L. Trumbo - One of the best experts on this subject based on the ideXlab platform.
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Synthesis, polymerization, and copolymerization of 2,6‐dimethyl‐nona‐2,6,8‐triene
Journal of Polymer Science Part A: Polymer Chemistry, 1996Co-Authors: David L. TrumboAbstract:Homopolymerization of 2,6-dimethylnona-2,6,8-triene (DMNT) was found to be sluggish, yielding low molecular weight materials of uncertain structure. Copolymerization with a variety of coMonomers proved facile. The Monomer in fact proved to be the more Reactive Monomer in most cases but increasing feed concentrations of DMNT resulted in lower copolymer yield and molecular weight
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Copolymerization of N-vinyl phthalamide with acrylate and methacrylate Monomers and preliminary analysis of the stereochemistry of poly(N-vinyl phthalamide)
Polymer Bulletin, 1995Co-Authors: David L. TrumboAbstract:N-Vinyl phthalamide was copolymerized with methyl methacrylate, isobutyl methacrylate or butyl acrylate. The copolymerizations were initiated free radically and it was necessary to conduct the polymerizations in solution or else insoluble products would result. In most cases the polymerizations preceded to relatively high conversions in a short time. The conversions necessitated the use of high conversion methods to calculate the reactivity ratios. The N-vinyl phthalamide was found to be the less Reactive Monomer in all cases. As part of this study, poly(N-vinyl phthalamide) homopolymer was synthesized by free radical initiation. While the ^1H-NMR spectrum yield very little information concerning polymer stereochemistry, the methine carbon resonance in the ^13C-NMR spectrum displayed a sensitivity to polymer stereochemistry.
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The copolymerization of substituted styrenes with α-methylene-γ-butyrolactone
Polymer Bulletin, 1995Co-Authors: David L. TrumboAbstract:Copolymers of halogenated styrenes and α-methylene-γ-butyrolactone were synthesized in bulk via free radical initiation. The polymerizations, in most cases, proceeded rapidly to high conversion. The high conversions obtained necessitated the use of high conversion methods to calculate reactivity ratios. In all the copolymerizations the α-methylene-γ-butyrolactone proved to be the more Reactive Monomer.
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Copolymerization of 2-methacryloxytropone with methyl methacrylate and ethyl acrylate
Polymer Bulletin, 1995Co-Authors: David L. TrumboAbstract:2-Methacryloxytropone was synthesized via reported methods and it's free radical initiated copolymerization with methyl methacrylate or ethyl acrylate was investigated. The 2-methacryloxytropone was found to be the more Reactive Monomer in both cases, however the difference in reactivity was more pronounced in the ethyl acrylate case.
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Copolymerization behavior of 2-vinyl-5-methyl furan
Polymer Bulletin, 1995Co-Authors: David L. TrumboAbstract:The title Monomer was copolymerized with methyl methacrylate, isobutyl methacrylate n-butyl acrylate. The results of the copolymerization experiments were analyzed using a nonlinear least squares error-invariables method in order to obtain reactivity ratios for each Monomer pair. In all cases the 2-vinyl-5-methyl furan proved to be the more Reactive Monomer, although this Monomer is not as Reactive as some other vinyl heterocycles have proved to be in copolymerizations with these same or similar coMonomers.
Dapawan Kunwong - One of the best experts on this subject based on the ideXlab platform.
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Curing behavior and cured film performance of easy-to-clean UV-curable coatings based on hybrid urethane acrylate oligomers
Journal of Polymer Research, 2012Co-Authors: Supranee Kaewpirom, Dapawan KunwongAbstract:This study aims to prepare different formulations of UV-curable coatings based on hybrid urethane acrylate oligomers and to characterize their UV-cured films for application as easy-to-clean coatings. The effects of Reactive Monomer functionality and the oligomer structure on the reaction rate and extent of UV curing were investigated as well as on the cured films properties. The study began with the synthesis of two different hybrid urethane acrylate oligomers and their chemical structures were characterized by NMR and FT-IR. Six formulations of UV-curable coating were prepared by varying the type of urethane acrylate oligomers in addition to the type of Reactive Monomers, using 2,2-dimethoxy-2-phenyl acetophenone as a photoinitiator, methacrylic acid as a Reactive diluent and 3-aminopropyltrimethoxysilane as a coupling agent. The UV curing process of such coatings was monitored by FT-IR and the C=C bond conversion was expressed. Finally, the weight loss, water contact angle, cross-cut adhesion and tensile properties of the UV-cured films were also investigated.
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Curing behavior of a UV-curable coating based on urethane acrylate oligomer: The influence of Reactive Monomers
Songklanakarin Journal of Science and Technology, 2011Co-Authors: Dapawan Kunwong, Natthawadee Sumanochitraporn, Supranee KaewpiromAbstract:A hybrid organic-organic urethane acrylate oligomer was synthesized by the reaction of polypropyleneglycol (PPG), 2,4-toluene diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) using dibutyltin dilaurate (DBTDL) as a catalyst. The urethane acrylate oligomer’s structure was characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). Two UV-curable coatings were prepared by blending the urethane acrylate oligomer, a Reactive Monomer (1,6- hexanediol diacrylate (HDDA) or trimethylol propane triacrylate (TMPTA)) and a photoinitiator (2,2-di- methoxy-2-phenyl acetophenone). The UV curing process of such coatings was monitored by FT-IR and determination of the gel fraction. It was found that as the UV dose increased, the specific peaks at 1635 cm-1 and 810 cm-1 , related to the carbon- carbon double (C=C) bond, decreased. Gel fraction of the cured coating film was found to increase with increasing radiation time. Thermal properties of the cured coating were also investigated using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA).
Supranee Kaewpirom - One of the best experts on this subject based on the ideXlab platform.
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Curing behavior and cured film performance of easy-to-clean UV-curable coatings based on hybrid urethane acrylate oligomers
Journal of Polymer Research, 2012Co-Authors: Supranee Kaewpirom, Dapawan KunwongAbstract:This study aims to prepare different formulations of UV-curable coatings based on hybrid urethane acrylate oligomers and to characterize their UV-cured films for application as easy-to-clean coatings. The effects of Reactive Monomer functionality and the oligomer structure on the reaction rate and extent of UV curing were investigated as well as on the cured films properties. The study began with the synthesis of two different hybrid urethane acrylate oligomers and their chemical structures were characterized by NMR and FT-IR. Six formulations of UV-curable coating were prepared by varying the type of urethane acrylate oligomers in addition to the type of Reactive Monomers, using 2,2-dimethoxy-2-phenyl acetophenone as a photoinitiator, methacrylic acid as a Reactive diluent and 3-aminopropyltrimethoxysilane as a coupling agent. The UV curing process of such coatings was monitored by FT-IR and the C=C bond conversion was expressed. Finally, the weight loss, water contact angle, cross-cut adhesion and tensile properties of the UV-cured films were also investigated.
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Curing behavior of a UV-curable coating based on urethane acrylate oligomer: The influence of Reactive Monomers
Songklanakarin Journal of Science and Technology, 2011Co-Authors: Dapawan Kunwong, Natthawadee Sumanochitraporn, Supranee KaewpiromAbstract:A hybrid organic-organic urethane acrylate oligomer was synthesized by the reaction of polypropyleneglycol (PPG), 2,4-toluene diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) using dibutyltin dilaurate (DBTDL) as a catalyst. The urethane acrylate oligomer’s structure was characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). Two UV-curable coatings were prepared by blending the urethane acrylate oligomer, a Reactive Monomer (1,6- hexanediol diacrylate (HDDA) or trimethylol propane triacrylate (TMPTA)) and a photoinitiator (2,2-di- methoxy-2-phenyl acetophenone). The UV curing process of such coatings was monitored by FT-IR and determination of the gel fraction. It was found that as the UV dose increased, the specific peaks at 1635 cm-1 and 810 cm-1 , related to the carbon- carbon double (C=C) bond, decreased. Gel fraction of the cured coating film was found to increase with increasing radiation time. Thermal properties of the cured coating were also investigated using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA).
H.-p.d. Shieh - One of the best experts on this subject based on the ideXlab platform.
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Splay-to-Bend Transition-Free Reactive Monomer Modified Pi-Cell
IEEE Photonics Technology Letters, 2009Co-Authors: Szu Fen F. Chen, Huang-ming Philip Chen, Liansing Chow, Yu-yun Chang, H.-p.d. ShiehAbstract:A Reactive Monomer modified Pi-cell (RMM-Pi-cell) comprising a layer of liquid crystal (LC) Reactive Monomer on one surface was prepared to control the surface pretilt angle. The simulation results suggested that a transition-free Pi-cell can be prepared by asymmetrical cell with one 8 deg pretilt angle and the other surface greater than 47deg when the cell gap was smaller than 4 mum. The nematic Reactive Monomer layer has a molecular average tilt angle over 80deg which allowed the LC molecules to be arranged in a favored bend state in the asymmetrical cell. The critical voltages cannot be found in all 3-mu m RMM-Pi-cells. The cell retardation data confirmed the initial bend orientation with zero voltage applied. Moreover, the light leakage of dark state was reduced. The contrast ratio of RMM-Pi-cell was improved by a factor of 11 compared with an original Pi-cell without using compensation film.
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P-125: Transition free, high contrast Reactive Monomer modified pi-cell
SID Symposium Digest of Technical Papers, 2009Co-Authors: Szu Fen F. Chen, Huang-ming Philip Chen, Yu-yun Chang, Liansing Culp Chow, H.-p.d. ShiehAbstract:The proposed Reactive Monomer modified Pi-cell (RMM-Pi-cell) can suppress its critical voltage to zero, i.e. state transition-free cell. The cell retardation data confirmed the initial bend orientation with zero voltage applied. The additional nematic Reactive Monomer (RM) layer possessed molecular average tilt angle over 80° which allowed the liquid crystal molecules arranged in favored bend state in 3μm cell. Moreover, the light leakage of dark state was reduced. The contrast ratio of RMM-Pi-cell was improved by a factor of 11 compared with an original Pi-cell without using compensation film.
Szu Fen F. Chen - One of the best experts on this subject based on the ideXlab platform.
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Splay-to-Bend Transition-Free Reactive Monomer Modified Pi-Cell
IEEE Photonics Technology Letters, 2009Co-Authors: Szu Fen F. Chen, Huang-ming Philip Chen, Liansing Chow, Yu-yun Chang, H.-p.d. ShiehAbstract:A Reactive Monomer modified Pi-cell (RMM-Pi-cell) comprising a layer of liquid crystal (LC) Reactive Monomer on one surface was prepared to control the surface pretilt angle. The simulation results suggested that a transition-free Pi-cell can be prepared by asymmetrical cell with one 8 deg pretilt angle and the other surface greater than 47deg when the cell gap was smaller than 4 mum. The nematic Reactive Monomer layer has a molecular average tilt angle over 80deg which allowed the LC molecules to be arranged in a favored bend state in the asymmetrical cell. The critical voltages cannot be found in all 3-mu m RMM-Pi-cells. The cell retardation data confirmed the initial bend orientation with zero voltage applied. Moreover, the light leakage of dark state was reduced. The contrast ratio of RMM-Pi-cell was improved by a factor of 11 compared with an original Pi-cell without using compensation film.
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P-125: Transition free, high contrast Reactive Monomer modified pi-cell
SID Symposium Digest of Technical Papers, 2009Co-Authors: Szu Fen F. Chen, Huang-ming Philip Chen, Yu-yun Chang, Liansing Culp Chow, H.-p.d. ShiehAbstract:The proposed Reactive Monomer modified Pi-cell (RMM-Pi-cell) can suppress its critical voltage to zero, i.e. state transition-free cell. The cell retardation data confirmed the initial bend orientation with zero voltage applied. The additional nematic Reactive Monomer (RM) layer possessed molecular average tilt angle over 80° which allowed the liquid crystal molecules arranged in favored bend state in 3μm cell. Moreover, the light leakage of dark state was reduced. The contrast ratio of RMM-Pi-cell was improved by a factor of 11 compared with an original Pi-cell without using compensation film.
