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Charlotte K Williams - One of the best experts on this subject based on the ideXlab platform.
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influences of a dizinc catalyst and bifunctional chain transfer agents on the polymer architecture in the ring opening Polymerization of e caprolactone
Macromolecules, 2015Co-Authors: Charles Romain, Valentin Poirier, Charlotte K WilliamsAbstract:The Polymerization of e-caprolactone is reported using various bifunctional chain transfer agents and a dizinc catalyst. Conventionally, it is assumed that using a bifunctional chain transfer agent (CTA), Polymerization will be Initiated from both functional groups; however, in this study this assumption is not always substantiated. The different architectures and microstructures of poly(e-caprolactone) samples (PCL) are compared using a series of bifunctional and monofunctional alcohols as the chain transfer agents, including trans-1,2-cyclohexanediol (CHD), ethylene glycol (EG), 1,2-propanediol (PD), poly(ethylene glycol) (PEG), 2-methyl-1,3-propanediol (MPD), 1-hexanol, 2-hexanol, and 2-methyl-2-pentanol. A mixture of two architectures is observed when diols containing secondary hydroxyls are used, such as cyclohexanediol or propanediol; there are chains that are both chain-extended and chain-terminated by the diol. These findings indicate that not all secondary hydroxyl groups Initiate Polymerization....
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influences of a dizinc catalyst and bifunctional chain transfer agents on the polymer architecture in the ring opening Polymerization of e caprolactone
Macromolecules, 2015Co-Authors: Charles Romain, Valentin Poirier, Charlotte K WilliamsAbstract:The Polymerization of e-caprolactone is reported using various bifunctional chain transfer agents and a dizinc catalyst. Conventionally, it is assumed that using a bifunctional chain transfer agent (CTA), Polymerization will be Initiated from both functional groups; however, in this study this assumption is not always substantiated. The different architectures and microstructures of poly(e-caprolactone) samples (PCL) are compared using a series of bifunctional and monofunctional alcohols as the chain transfer agents, including trans-1,2-cyclohexanediol (CHD), ethylene glycol (EG), 1,2-propanediol (PD), poly(ethylene glycol) (PEG), 2-methyl-1,3-propanediol (MPD), 1-hexanol, 2-hexanol, and 2-methyl-2-pentanol. A mixture of two architectures is observed when diols containing secondary hydroxyls are used, such as cyclohexanediol or propanediol; there are chains that are both chain-extended and chain-terminated by the diol. These findings indicate that not all secondary hydroxyl groups Initiate Polymerization....
Charles Romain - One of the best experts on this subject based on the ideXlab platform.
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influences of a dizinc catalyst and bifunctional chain transfer agents on the polymer architecture in the ring opening Polymerization of e caprolactone
Macromolecules, 2015Co-Authors: Charles Romain, Valentin Poirier, Charlotte K WilliamsAbstract:The Polymerization of e-caprolactone is reported using various bifunctional chain transfer agents and a dizinc catalyst. Conventionally, it is assumed that using a bifunctional chain transfer agent (CTA), Polymerization will be Initiated from both functional groups; however, in this study this assumption is not always substantiated. The different architectures and microstructures of poly(e-caprolactone) samples (PCL) are compared using a series of bifunctional and monofunctional alcohols as the chain transfer agents, including trans-1,2-cyclohexanediol (CHD), ethylene glycol (EG), 1,2-propanediol (PD), poly(ethylene glycol) (PEG), 2-methyl-1,3-propanediol (MPD), 1-hexanol, 2-hexanol, and 2-methyl-2-pentanol. A mixture of two architectures is observed when diols containing secondary hydroxyls are used, such as cyclohexanediol or propanediol; there are chains that are both chain-extended and chain-terminated by the diol. These findings indicate that not all secondary hydroxyl groups Initiate Polymerization....
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influences of a dizinc catalyst and bifunctional chain transfer agents on the polymer architecture in the ring opening Polymerization of e caprolactone
Macromolecules, 2015Co-Authors: Charles Romain, Valentin Poirier, Charlotte K WilliamsAbstract:The Polymerization of e-caprolactone is reported using various bifunctional chain transfer agents and a dizinc catalyst. Conventionally, it is assumed that using a bifunctional chain transfer agent (CTA), Polymerization will be Initiated from both functional groups; however, in this study this assumption is not always substantiated. The different architectures and microstructures of poly(e-caprolactone) samples (PCL) are compared using a series of bifunctional and monofunctional alcohols as the chain transfer agents, including trans-1,2-cyclohexanediol (CHD), ethylene glycol (EG), 1,2-propanediol (PD), poly(ethylene glycol) (PEG), 2-methyl-1,3-propanediol (MPD), 1-hexanol, 2-hexanol, and 2-methyl-2-pentanol. A mixture of two architectures is observed when diols containing secondary hydroxyls are used, such as cyclohexanediol or propanediol; there are chains that are both chain-extended and chain-terminated by the diol. These findings indicate that not all secondary hydroxyl groups Initiate Polymerization....
Yusuf Yagci - One of the best experts on this subject based on the ideXlab platform.
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highly efficient dandelion like near infrared light photoinitiator for free radical and thiol ene photoPolymerizations
Nature Communications, 2019Co-Authors: Xiucheng Zou, Yusuf Yagci, Feng Shi, Ren LiuAbstract:Efficient photoPolymerization activated by nonharmful near-infrared (NIR) light is important for various biological applications. Here we propose a NIR light free-radical photoinitiator (PI) fabricated by incorporating oxime-ester coumarin functionality on the surface of upconversion nanoparticles (UCNPs). The coumarin groups of PI absorb the light emitted from the UCNP core, whereas the oxime ester groups undergo cleavage to form radicals. Upon irradiation at 980 nm, the mobile radicals, formed in a manner similar to that of dandelion seed release, Initiate both free-radical and thiol-ene photoPolymerizations. The superior efficiency of dandelion-like PIs assisted photoPolymerizations can be attributed to the reduction of energy loss and increased local PI concentration due to Forster resonance energy transfer process and confinement effect, respectively. Moreover, the proposed PI system can Initiate Polymerization under low-power NIR laser and reduces the thermal side effects. The possibility of its potential use in deep curing applications was also demonstrated. Photo-induced Polymerizations are being utilized to design and fabricate macromolecular structures with spatial and temporal control. Here the authors use a near-infrared light free-radical photoinitiator consisting of oxime-ester coumarin functionalities on the surface of upconversion nanoparticles for free-radical and thiol-ene photoPolymerizations.
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thioxanthone carbazole as a visible light photoinitiator for free radical Polymerization
Journal of Polymer Science Part A, 2010Co-Authors: Gorkem Yilmaz, Alev Tuzu, Yusuf YagciAbstract:A thioxanthone (TX) derivative with the additional carbazole chromophore, namely thioxanthone-carbazole (TX-C) was synthesized and characterized. The photophysical properties and its efficiency to polymerize methyl methacrylate both in the presence and absence of N,N-dimethylaniline (DMA) as coinitia- tor was investigated and compared with that of the commercially available TX. TX-C was found to display better photophysical properties and in both cases Initiate Polymerization more effi- ciently. Detailed real-time Fourier transform infrared studies revealed that high Polymerization rates can be obtained when TX-C in conjunction with DMA was used. V C 2010 Wiley Periodi- cals, Inc. J Polym Sci Part A: Polym Chem 48: 5120-5125, 2010
Valentin Poirier - One of the best experts on this subject based on the ideXlab platform.
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influences of a dizinc catalyst and bifunctional chain transfer agents on the polymer architecture in the ring opening Polymerization of e caprolactone
Macromolecules, 2015Co-Authors: Charles Romain, Valentin Poirier, Charlotte K WilliamsAbstract:The Polymerization of e-caprolactone is reported using various bifunctional chain transfer agents and a dizinc catalyst. Conventionally, it is assumed that using a bifunctional chain transfer agent (CTA), Polymerization will be Initiated from both functional groups; however, in this study this assumption is not always substantiated. The different architectures and microstructures of poly(e-caprolactone) samples (PCL) are compared using a series of bifunctional and monofunctional alcohols as the chain transfer agents, including trans-1,2-cyclohexanediol (CHD), ethylene glycol (EG), 1,2-propanediol (PD), poly(ethylene glycol) (PEG), 2-methyl-1,3-propanediol (MPD), 1-hexanol, 2-hexanol, and 2-methyl-2-pentanol. A mixture of two architectures is observed when diols containing secondary hydroxyls are used, such as cyclohexanediol or propanediol; there are chains that are both chain-extended and chain-terminated by the diol. These findings indicate that not all secondary hydroxyl groups Initiate Polymerization....
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influences of a dizinc catalyst and bifunctional chain transfer agents on the polymer architecture in the ring opening Polymerization of e caprolactone
Macromolecules, 2015Co-Authors: Charles Romain, Valentin Poirier, Charlotte K WilliamsAbstract:The Polymerization of e-caprolactone is reported using various bifunctional chain transfer agents and a dizinc catalyst. Conventionally, it is assumed that using a bifunctional chain transfer agent (CTA), Polymerization will be Initiated from both functional groups; however, in this study this assumption is not always substantiated. The different architectures and microstructures of poly(e-caprolactone) samples (PCL) are compared using a series of bifunctional and monofunctional alcohols as the chain transfer agents, including trans-1,2-cyclohexanediol (CHD), ethylene glycol (EG), 1,2-propanediol (PD), poly(ethylene glycol) (PEG), 2-methyl-1,3-propanediol (MPD), 1-hexanol, 2-hexanol, and 2-methyl-2-pentanol. A mixture of two architectures is observed when diols containing secondary hydroxyls are used, such as cyclohexanediol or propanediol; there are chains that are both chain-extended and chain-terminated by the diol. These findings indicate that not all secondary hydroxyl groups Initiate Polymerization....
Kristi S Anseth - One of the best experts on this subject based on the ideXlab platform.
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glucose oxidase mediated Polymerization as a platform for dual mode signal amplification and biodetection
Biotechnology and Bioengineering, 2011Co-Authors: Brad J Berron, Kristi S Anseth, Leah M Johnson, Joshua D Mccall, Nicholas J Alvey, Christopher N. BowmanAbstract:We report the first use of a Polymerization-based ELISA substrate solution employing enzymatically mediated radical Polymerization as a dual-mode amplification strategy. Enzymes are selectively coupled to surfaces to generate radicals that subsequently lead to Polymerization-based amplification (PBA) and biodetection. Sensitivity and amplification of the Polymerization-based detection system were optimized in a microwell strip format using a biotinylated microwell surface with a glucose oxidase (GOx)–avidin conjugate. The immobilized GOx is used to Initiate Polymerization, enabling the detection of the biorecognition event visually or through the use of a plate reader. Assay response is compared to that of an enzymatic substrate utilizing nitroblue tetrazolium in a simplified assay using biotinylated wells. The Polymerization substrate exhibits equivalent sensitivity (2 µg/mL of GOx-avidin) and over three times greater signal amplification than this traditional enzymatic substrate since each radical that is enzymatically generated leads to a large number of Polymerization events. Enzyme-mediated Polymerization proceeds in an ambient atmosphere without the need for external energy sources, which is an improvement upon previous PBA platforms. Substrate formulations are highly sensitive to both glucose and iron concentrations at the lowest enzyme concentrations. Increases in amplification time correspond to higher assay sensitivities with no increase in non-specific signal. Finally, the Polymerization substrate generated a signal to noise ratio of 14 at the detection limit (156 ng/mL) in an assay of transforming growth factor-beta. Biotechnol. Bioeng. 2011; 108:1521–1528. © 2011 Wiley Periodicals, Inc.
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photoInitiated Polymerization of peg diacrylate with lithium phenyl 2 4 6 trimethylbenzoylphosphinate Polymerization rate and cytocompatibility
Biomaterials, 2009Co-Authors: Benjamin D Fairbanks, Michael P Schwartz, Kristi S Anseth, Christopher N. BowmanAbstract:Due to mild reaction conditions and temporal and spatial control over material formation, photoPolymerization has become a valuable technique for the encapsulation of living cells in three dimensional, hydrated, biomimetic materials. For such applications, 2-hydroxy-1-[4-(2-hydroxyethoxy) phenyl]-2-methyl-1-propanone (I2959) is the most commonly used photoinitiator (by virtue of its moderate water solubility), yet this initiator has an absorption spectrum that is poorly matched with wavelengths of light generally regarded as benign to living cells, limiting the rate at which it may Initiate Polymerization in their presence. In contrast, acylphosphine oxide photoinitiators, generally exhibit absorption spectra at wavelengths suitable for cell encapsulation, yet commercially available initiators of this class have low water solubility. Here, a water soluble lithium acylphosphinate salt is evaluated for its ability to polymerize diacrylated poly(ethylene glycol) (PEGDA) monomers rapidly into hydrogels, while maintaining high viability during direct encapsulation of cells. Through rheometric measurements, the time to reach gelation of a PEGDA solution with the phosphinate initiator is one tenth the time for that using I2959 at similar concentrations, when exposed to 365 nm light. Further, Polymerization with the phosphinate initiator at 405 nm visible light exposure is achieved with low initiator concentrations and light intensities, precluded in Polymerizations Initiated with I2959 by its absorbance profile. When examined 24 h after encapsulation, survival rates of human neonatal fibroblasts encapsulated in hydrogels polymerized with the phosphinate initiator exceed 95%, demonstrating the cytocompatibility of this initiating system.