The Experts below are selected from a list of 1548 Experts worldwide ranked by ideXlab platform
Jeffrey S. Moore - One of the best experts on this subject based on the ideXlab platform.
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cyclic poly Phthalaldehyde thermoforming a bulk transient material
ACS Macro Letters, 2018Co-Authors: Adam M Feinberg, Christopher L Plantz, Edgar B Mejia, Scott R. White, Hector Lopez Hernandez, Nancy R. Sottos, Jeffrey S. MooreAbstract:Cyclic poly(Phthalaldehyde) (cPPA) is a metastable and stimuli responsive polymer that undergoes rapid solid state depolymerization and has been utilized as a packaging and encapsulating material for transient applications. However, the early onset thermal depolymerization of cPPA severely hinders the fabrication and processing of plastic parts. Herein, the thermally triggered depolymerization of cPPA was investigated and tailored to enable thermal processing and molding of cPPA at moderate temperatures below the thermal depolymerization temperature. Stabilization of cPPA at elevated temperature was accomplished by removal of the latent Lewis acid catalyst BF3 and by addition of radical inhibitors and a Lewis base. Addition of a plasticizer to the stabilized cPPA enabled the fabrication of a monolithic solid polymer via hot press molding. Importantly, it is shown that the thermally processed cPPA retains its stimuli responsive depolymerization capability and will enable future work in the fabrication of b...
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Cyclic Poly(Phthalaldehyde): Thermoforming a Bulk Transient Material
2017Co-Authors: Adam M Feinberg, Christopher L Plantz, Hector Lopez Hernandez, Nancy R. Sottos, Edgar B. Mejia, Scott R. White, Jeffrey S. MooreAbstract:Cyclic poly(Phthalaldehyde) (cPPA) is a metastable and stimuli responsive polymer that undergoes rapid solid state depolymerization and has been utilized as a packaging and encapsulating material for transient applications. However, the early onset thermal depolymerization of cPPA severely hinders the fabrication and processing of plastic parts. Herein, the thermally triggered depolymerization of cPPA was investigated and tailored to enable thermal processing and molding of cPPA at moderate temperatures below the thermal depolymerization temperature. Stabilization of cPPA at elevated temperature was accomplished by removal of the latent Lewis acid catalyst BF3 and by addition of radical inhibitors and a Lewis base. Addition of a plasticizer to the stabilized cPPA enabled the fabrication of a monolithic solid polymer via hot press molding. Importantly, it is shown that the thermally processed cPPA retains its stimuli responsive depolymerization capability and will enable future work in the fabrication of bulk plastic parts that depolymerize and disintegrate on demand
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End Group Characterization of Poly(Phthalaldehyde): Surprising Discovery of a Reversible, Cationic Macrocyclization Mechanism
2016Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:End-capped poly(Phthalaldehyde) (PPA) synthesized by anionic polymerization has garnered significant interest due to its ease of synthesis and rapid depolymerization. However, alternative ionic polymerizations to produce PPA have been largely unexplored. In this report, we demonstrate that a cationic polymerization of o-Phthalaldehyde initiated by boron trifluoride results in cyclic PPA in high yield, with high molecular weight, and with extremely high cyclic purity. The cyclic structure is confirmed by NMR spectroscopy, MALDI-TOF mass spectrometry, and triple-detection GPC. The cyclic polymers are reversibly opened and closed under the polymerization conditions. Owing to PPA’s low ceiling temperature, cyclic PPA is capable of chain extension to larger molecular weights, controlled depolymerization to smaller molecular weights, or dynamic intermixing with other polymer chains, both cyclics and end-capped linears. These unusual properties endow the system with great flexibility in the synthesis and isolation of pure cyclic polymers of high molecular weight. Further, we speculate that the absence of end groups enhances the stability of cyclic PPA and makes it an attractive candidate for lithographic applications
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divergent macrocyclization mechanisms in the cationic initiated polymerization of ethyl glyoxylate
Macromolecules, 2014Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:We recently discovered that the cationic polymerization of o-Phthalaldehyde generates cyclic poly(Phthalaldehyde) in high yield, high molecular weight, and a high degree of cyclic purity. Given this surprising result, we pursued the cationic polymerization of ethyl glyoxylate to determine if the macrocyclization outcome is, in fact, a general trend of low ceiling temperature polyacetals. Using NMR spectroscopy, MALDI-TOF mass spectrometry, and triple detection GPC, we have uncovered divergent macrocyclization mechanisms in the cationic polymerization of ethyl glyoxylate. Backbiting is observed either via the backbone acetal or via the pendant ester to give disparate polymer products and unique polymer architectures. The favored route for cyclization is found to depend on both the monomer concentration and the initiating species. Understanding the underlying mechanisms of polymerization and the ability to rigorously control polymer structure has important implications for the design of new transient materials.
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Divergent Macrocyclization Mechanisms in the Cationic Initiated Polymerization of Ethyl Glyoxylate
2014Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:We recently discovered that the cationic polymerization of o-Phthalaldehyde generates cyclic poly(Phthalaldehyde) in high yield, high molecular weight, and a high degree of cyclic purity. Given this surprising result, we pursued the cationic polymerization of ethyl glyoxylate to determine if the macrocyclization outcome is, in fact, a general trend of low ceiling temperature polyacetals. Using NMR spectroscopy, MALDI-TOF mass spectrometry, and triple detection GPC, we have uncovered divergent macrocyclization mechanisms in the cationic polymerization of ethyl glyoxylate. Backbiting is observed either via the backbone acetal or via the pendant ester to give disparate polymer products and unique polymer architectures. The favored route for cyclization is found to depend on both the monomer concentration and the initiating species. Understanding the underlying mechanisms of polymerization and the ability to rigorously control polymer structure has important implications for the design of new transient materials
Joshua A. Kaitz - One of the best experts on this subject based on the ideXlab platform.
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End Group Characterization of Poly(Phthalaldehyde): Surprising Discovery of a Reversible, Cationic Macrocyclization Mechanism
2016Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:End-capped poly(Phthalaldehyde) (PPA) synthesized by anionic polymerization has garnered significant interest due to its ease of synthesis and rapid depolymerization. However, alternative ionic polymerizations to produce PPA have been largely unexplored. In this report, we demonstrate that a cationic polymerization of o-Phthalaldehyde initiated by boron trifluoride results in cyclic PPA in high yield, with high molecular weight, and with extremely high cyclic purity. The cyclic structure is confirmed by NMR spectroscopy, MALDI-TOF mass spectrometry, and triple-detection GPC. The cyclic polymers are reversibly opened and closed under the polymerization conditions. Owing to PPA’s low ceiling temperature, cyclic PPA is capable of chain extension to larger molecular weights, controlled depolymerization to smaller molecular weights, or dynamic intermixing with other polymer chains, both cyclics and end-capped linears. These unusual properties endow the system with great flexibility in the synthesis and isolation of pure cyclic polymers of high molecular weight. Further, we speculate that the absence of end groups enhances the stability of cyclic PPA and makes it an attractive candidate for lithographic applications
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divergent macrocyclization mechanisms in the cationic initiated polymerization of ethyl glyoxylate
Macromolecules, 2014Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:We recently discovered that the cationic polymerization of o-Phthalaldehyde generates cyclic poly(Phthalaldehyde) in high yield, high molecular weight, and a high degree of cyclic purity. Given this surprising result, we pursued the cationic polymerization of ethyl glyoxylate to determine if the macrocyclization outcome is, in fact, a general trend of low ceiling temperature polyacetals. Using NMR spectroscopy, MALDI-TOF mass spectrometry, and triple detection GPC, we have uncovered divergent macrocyclization mechanisms in the cationic polymerization of ethyl glyoxylate. Backbiting is observed either via the backbone acetal or via the pendant ester to give disparate polymer products and unique polymer architectures. The favored route for cyclization is found to depend on both the monomer concentration and the initiating species. Understanding the underlying mechanisms of polymerization and the ability to rigorously control polymer structure has important implications for the design of new transient materials.
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Divergent Macrocyclization Mechanisms in the Cationic Initiated Polymerization of Ethyl Glyoxylate
2014Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:We recently discovered that the cationic polymerization of o-Phthalaldehyde generates cyclic poly(Phthalaldehyde) in high yield, high molecular weight, and a high degree of cyclic purity. Given this surprising result, we pursued the cationic polymerization of ethyl glyoxylate to determine if the macrocyclization outcome is, in fact, a general trend of low ceiling temperature polyacetals. Using NMR spectroscopy, MALDI-TOF mass spectrometry, and triple detection GPC, we have uncovered divergent macrocyclization mechanisms in the cationic polymerization of ethyl glyoxylate. Backbiting is observed either via the backbone acetal or via the pendant ester to give disparate polymer products and unique polymer architectures. The favored route for cyclization is found to depend on both the monomer concentration and the initiating species. Understanding the underlying mechanisms of polymerization and the ability to rigorously control polymer structure has important implications for the design of new transient materials
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dynamic covalent macrocyclic poly Phthalaldehyde s scrambling cyclic homopolymer mixtures produces multi block and random cyclic copolymers
Macromolecules, 2013Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:We recently reported the cationic polymerization of o-Phthalaldehyde to macrocyclic poly(Phthalaldehyde) polymers. Resubjecting the cyclic polymers to the polymerization conditions led to a redistribution of the polymer to a new cyclic structure consistent with thermodynamic equilibrium. We now report the synthesis of cyclic poly(Phthalaldehyde) derivatives and demonstrate the scrambling of distinct homopolymer mixtures to copolymers under the cationic polymerization conditions. Homopolymer mixtures are found to rapidly redistribute, first to multiblock cyclic copolymers. With extended reaction time, random macrocyclic copolymers are obtained. Evolution of the microstructure was monitored by NMR spectroscopy, MALDI–TOF mass spectrometry, and gel permeation chromatography (GPC). The reported scrambling method leads to the rapid preparation of macrocyclic copolymers of high molecular weight with variable microstructure depending on reaction times and catalyst loadings.
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end group characterization of poly Phthalaldehyde surprising discovery of a reversible cationic macrocyclization mechanism
Journal of the American Chemical Society, 2013Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:End-capped poly(Phthalaldehyde) (PPA) synthesized by anionic polymerization has garnered significant interest due to its ease of synthesis and rapid depolymerization. However, alternative ionic polymerizations to produce PPA have been largely unexplored. In this report, we demonstrate that a cationic polymerization of o-Phthalaldehyde initiated by boron trifluoride results in cyclic PPA in high yield, with high molecular weight, and with extremely high cyclic purity. The cyclic structure is confirmed by NMR spectroscopy, MALDI-TOF mass spectrometry, and triple-detection GPC. The cyclic polymers are reversibly opened and closed under the polymerization conditions. Owing to PPA’s low ceiling temperature, cyclic PPA is capable of chain extension to larger molecular weights, controlled depolymerization to smaller molecular weights, or dynamic intermixing with other polymer chains, both cyclics and end-capped linears. These unusual properties endow the system with great flexibility in the synthesis and isolati...
Charles E. Diesendruck - One of the best experts on this subject based on the ideXlab platform.
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End Group Characterization of Poly(Phthalaldehyde): Surprising Discovery of a Reversible, Cationic Macrocyclization Mechanism
2016Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:End-capped poly(Phthalaldehyde) (PPA) synthesized by anionic polymerization has garnered significant interest due to its ease of synthesis and rapid depolymerization. However, alternative ionic polymerizations to produce PPA have been largely unexplored. In this report, we demonstrate that a cationic polymerization of o-Phthalaldehyde initiated by boron trifluoride results in cyclic PPA in high yield, with high molecular weight, and with extremely high cyclic purity. The cyclic structure is confirmed by NMR spectroscopy, MALDI-TOF mass spectrometry, and triple-detection GPC. The cyclic polymers are reversibly opened and closed under the polymerization conditions. Owing to PPA’s low ceiling temperature, cyclic PPA is capable of chain extension to larger molecular weights, controlled depolymerization to smaller molecular weights, or dynamic intermixing with other polymer chains, both cyclics and end-capped linears. These unusual properties endow the system with great flexibility in the synthesis and isolation of pure cyclic polymers of high molecular weight. Further, we speculate that the absence of end groups enhances the stability of cyclic PPA and makes it an attractive candidate for lithographic applications
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divergent macrocyclization mechanisms in the cationic initiated polymerization of ethyl glyoxylate
Macromolecules, 2014Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:We recently discovered that the cationic polymerization of o-Phthalaldehyde generates cyclic poly(Phthalaldehyde) in high yield, high molecular weight, and a high degree of cyclic purity. Given this surprising result, we pursued the cationic polymerization of ethyl glyoxylate to determine if the macrocyclization outcome is, in fact, a general trend of low ceiling temperature polyacetals. Using NMR spectroscopy, MALDI-TOF mass spectrometry, and triple detection GPC, we have uncovered divergent macrocyclization mechanisms in the cationic polymerization of ethyl glyoxylate. Backbiting is observed either via the backbone acetal or via the pendant ester to give disparate polymer products and unique polymer architectures. The favored route for cyclization is found to depend on both the monomer concentration and the initiating species. Understanding the underlying mechanisms of polymerization and the ability to rigorously control polymer structure has important implications for the design of new transient materials.
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Divergent Macrocyclization Mechanisms in the Cationic Initiated Polymerization of Ethyl Glyoxylate
2014Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:We recently discovered that the cationic polymerization of o-Phthalaldehyde generates cyclic poly(Phthalaldehyde) in high yield, high molecular weight, and a high degree of cyclic purity. Given this surprising result, we pursued the cationic polymerization of ethyl glyoxylate to determine if the macrocyclization outcome is, in fact, a general trend of low ceiling temperature polyacetals. Using NMR spectroscopy, MALDI-TOF mass spectrometry, and triple detection GPC, we have uncovered divergent macrocyclization mechanisms in the cationic polymerization of ethyl glyoxylate. Backbiting is observed either via the backbone acetal or via the pendant ester to give disparate polymer products and unique polymer architectures. The favored route for cyclization is found to depend on both the monomer concentration and the initiating species. Understanding the underlying mechanisms of polymerization and the ability to rigorously control polymer structure has important implications for the design of new transient materials
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dynamic covalent macrocyclic poly Phthalaldehyde s scrambling cyclic homopolymer mixtures produces multi block and random cyclic copolymers
Macromolecules, 2013Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:We recently reported the cationic polymerization of o-Phthalaldehyde to macrocyclic poly(Phthalaldehyde) polymers. Resubjecting the cyclic polymers to the polymerization conditions led to a redistribution of the polymer to a new cyclic structure consistent with thermodynamic equilibrium. We now report the synthesis of cyclic poly(Phthalaldehyde) derivatives and demonstrate the scrambling of distinct homopolymer mixtures to copolymers under the cationic polymerization conditions. Homopolymer mixtures are found to rapidly redistribute, first to multiblock cyclic copolymers. With extended reaction time, random macrocyclic copolymers are obtained. Evolution of the microstructure was monitored by NMR spectroscopy, MALDI–TOF mass spectrometry, and gel permeation chromatography (GPC). The reported scrambling method leads to the rapid preparation of macrocyclic copolymers of high molecular weight with variable microstructure depending on reaction times and catalyst loadings.
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end group characterization of poly Phthalaldehyde surprising discovery of a reversible cationic macrocyclization mechanism
Journal of the American Chemical Society, 2013Co-Authors: Joshua A. Kaitz, Charles E. Diesendruck, Jeffrey S. MooreAbstract:End-capped poly(Phthalaldehyde) (PPA) synthesized by anionic polymerization has garnered significant interest due to its ease of synthesis and rapid depolymerization. However, alternative ionic polymerizations to produce PPA have been largely unexplored. In this report, we demonstrate that a cationic polymerization of o-Phthalaldehyde initiated by boron trifluoride results in cyclic PPA in high yield, with high molecular weight, and with extremely high cyclic purity. The cyclic structure is confirmed by NMR spectroscopy, MALDI-TOF mass spectrometry, and triple-detection GPC. The cyclic polymers are reversibly opened and closed under the polymerization conditions. Owing to PPA’s low ceiling temperature, cyclic PPA is capable of chain extension to larger molecular weights, controlled depolymerization to smaller molecular weights, or dynamic intermixing with other polymer chains, both cyclics and end-capped linears. These unusual properties endow the system with great flexibility in the synthesis and isolati...
Yang Zhen - One of the best experts on this subject based on the ideXlab platform.
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One-Pot Syntheses of Isoquinolin-3-ones and Benzo-1,4-diazepin-2,5-diones Utilizing Ugi-4CR Post-Transformation Strategy
acs combinatorial science, 2013Co-Authors: Che Chao, Li Song, Yu Zhixiong, Li Fangfang, Xin Shengchang, Zhou Liyan, Lin Shuo, Yang ZhenAbstract:One-pot and efficient syntheses of structurally diverse isoquinolin-3-ones and isoquinolin-3-one-based benzo-1,4-diazepin-2,5-diones have been developed. The notable features of the process include the Ugi condensation of monomasked Phthalaldehydes with amines, carboxylic acids, and isonitriles, followed by HClO4-mediated intramolecular condensation of the carbonyl with amide.Chemistry, AppliedChemistry, MedicinalChemistry, MultidisciplinarySCI(E)PubMed9ARTICLE4202-2071
Che Chao - One of the best experts on this subject based on the ideXlab platform.
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One-Pot Syntheses of Isoquinolin-3-ones and Benzo-1,4-diazepin-2,5-diones Utilizing Ugi-4CR Post-Transformation Strategy
acs combinatorial science, 2013Co-Authors: Che Chao, Li Song, Yu Zhixiong, Li Fangfang, Xin Shengchang, Zhou Liyan, Lin Shuo, Yang ZhenAbstract:One-pot and efficient syntheses of structurally diverse isoquinolin-3-ones and isoquinolin-3-one-based benzo-1,4-diazepin-2,5-diones have been developed. The notable features of the process include the Ugi condensation of monomasked Phthalaldehydes with amines, carboxylic acids, and isonitriles, followed by HClO4-mediated intramolecular condensation of the carbonyl with amide.Chemistry, AppliedChemistry, MedicinalChemistry, MultidisciplinarySCI(E)PubMed9ARTICLE4202-2071