Article
Polymer Science
Yuka Takahashi, Arihiro Kanazawa, Sadahito Aoshima
Summary: 3-Alkoxyphthalides (ROPTs) are candidate monomers that react with cationic species to generate oxocarbenium ions. This study focused on the cationic polymerization of ROPTs with oxiranes, and found that homopolymerization did not occur, while copolymerization with oxiranes proceeded smoothly. Copolymer degradation under acidic conditions was observed due to acetal cleavage from ROPT to oxirane. The successful terpolymerization of VE, oxirane, and ROPT resulted in ABC-type pseudo-periodic terpolymers under optimized conditions.
Article
Polymer Science
Daisuke Hotta, Arihiro Kanazawa, Sadahito Aoshima
Summary: tert-Butyl esters play a crucial role as chain transfer agents in the cationic copolymerization, liberating tert-butyl cations to facilitate the chain transfer process. The chain transfer reactions by tert-butyl esters potentially occur reversibly through the reaction of the propagating cation with the ester group at the omega-end of another chain.
MACROMOLECULAR RAPID COMMUNICATIONS
(2021)
Article
Polymer Science
Kana Takebayashi, Arihiro Kanazawa, Sadahito Aoshima
Summary: The cationic ring-opening copolymerization of cyclic acetals and 1,3-dioxolan-4-ones (DOLOs) was investigated, with a focus on understanding the polymerization mechanisms. The copolymerization of 1,3-dioxepane and 5-methyl-1,3-dioxolan-4-one successfully occurred using CF3SO3H as a catalyst, resulting in high molecular weight copolymers. NMR spectrometry and electrospray ionization mass spectrometry were used to analyze the detailed structure of the copolymers, which indicated that the copolymerization proceeds through an activated monomer mechanism involving the reaction of a hydroxy group and a proton-attached DOLO. Acid-catalyzed transacetalization reactions also likely occurred during the copolymerization process.
Article
Polymer Science
Yili Yang, Keman Yu, Shan Liu, Jieyu Yan, Haiwang Lai, Feiyue Xing, Pu Xiao
Summary: The research demonstrates a method to efficiently assemble vinyl monomers in defined orders to produce sequence-defined oligomers with potential biomedical applications, including the ability to degrade into shorter fragments and exhibit biocompatibility and cytotoxicity.
Article
Chemistry, Multidisciplinary
Wenqi Wang, Zefeng Zhou, Devavrat Sathe, Xuanting Tang, Stephanie Moran, Jing Jin, Fredrik Haeffner, Junpeng Wang, Jia Niu
Summary: This study presents a photocatalytic approach to generate degradable vinyl random copolymers with even distribution of labile functional groups in the polymer backbone. Reversible inhibition of chain propagation by in situ generated sulfur dioxide was overcome by reducing its solubility. The resulting degradable vinyl copolymers exhibited comparable material properties to non-degradable vinyl polymers.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Yui Kawamura, Daisuke Hotta, Arihiro Kanazawa, Sadahito Aoshima
Summary: The types and numbers of alkyl substituents were found to affect the reactivity of oxiranes in cationic copolymerization with alkyl vinyl ethers. Oxiranes with bulkier substituents showed lower reactivity, while oxiranes with fused ring structures exhibited higher reactivities. These results provide a systematic understanding of the polymerizability of oxiranes.
Article
Polymer Science
Zhitao Hu, Xiaohui Cao, Xiaohui Zhang, Bin Wu, Wenjun Luo, Huahua Huang, Le Li, Yongming Chen
Summary: A fast and controlled ring-opening polymerization method was reported to prepare PEG-like polyesters, poly(O-15C5), with potential biodegradability and improved immune responses.
Article
Chemistry, Multidisciplinary
Keita Kuroda, Makoto Ouchi
Summary: This study reveals the peculiar isomerization propagation of benzyl vinyl ether with an electron-deficient acrylate in radical copolymerization. The backward isomerization of the radical species leads to a periodic consumption and allows the introduction of a benzyl ether structure in the resulting copolymer, leading to efficient degradation under acid conditions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Polymer Science
Junichi Azuma, Arihiro Kanazawa, Sadahito Aoshima
Summary: Vinyl acetate (VAc) exhibits cationic polymerizability and can react with suitable comonomers to produce alternating copolymers or branched copolymers. Detailed analysis of the polymerization products can reveal the mechanisms of these copolymerization reactions.
Article
Polymer Science
Oleksandr Ivanchenko, Ugo Authesserre, Guilhem Coste, Stephane Mazieres, Mathias Destarac, Simon Harrisson
Summary: ε-Thionocaprolactone (TCL) can be easily copolymerized with vinyl esters to form degradable copolymers, with the molecular weight and dispersity controlled through xanthate-mediated RAFT polymerization. Analysis of the copolymer structure reveals a high level of TCL-TCL dyads, suggesting that the terminal copolymerization model is not accurate for describing TCL copolymerization.
Article
Polymer Science
Ankita Mandal, Indradip Mandal, Andreas F. M. Kilbinger
Summary: In this study, commercially available Vince lactam and its derivatives were copolymerized with 2,3-dihydrofuran (DHF) in a living fashion based on the unique reactivity of Ru Fischer carbene. The resulting copolymers showed complete degradation into small molecules under mildly acidic conditions, indicating uniform incorporation of the DHF units throughout the polymer backbone. The high metathesis activity and regioselectivity of vinyl ethers were further exploited for the synthesis of degradable copolymers using vinyl ethers as effective chain transfer agents. This cost-effective and environmentally friendly synthesis of degradable polymers has potential applications in biomedical and environmental fields.
Article
Polymer Science
Ankita Mandal, Subhajit Pal, Andreas F. M. Kilbinger
Summary: A new heterocyclic monomer is synthesized via Diels-Alder reaction and exhibits reluctant polymerization in dichloromethane (DCM) but facile polymerization in tetrahydrofuran using Grubbs' third generation catalyst (G3), with excellent control over molecular weight and dispersities. The removal of tert-butoxycarbonyl group from the polymeric backbone yields a water-soluble ring opening metathesis polymerization (ROMP) polymer. In DCM, this monomer can also copolymerize with 2,3-dihydrofuran under catalytic living ROMP conditions to produce backbone degradable polymers. All synthesized polymers are characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy. This new method for preparing water-soluble ROMP homopolymers and cost-effective degradable copolymers and block-copolymers may have potential applications in biomedicine.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Polymer Science
Dong-Yang Zhang, Dong Han, Yue Li, Dian-Feng Chen
Summary: This research reports an efficient light-driven ring-opening polymerization method for synthesizing unsaturated linear polymers with predictable molecular weight and low dispersity. The study shows that this light-driven system tolerates active pentafluorophenyl ester groups and allows for quantitative post-modifications.
Article
Polymer Science
Stefania Aivali, Peisen Yuan, Julianna Panidi, Dimitra G. Georgiadou, Themis Prodromakis, Joannis K. Kallitsis, Panagiotis E. Keivanidis, Aikaterini K. Andreopoulou
Summary: A processable n-type terpolymer was developed based on a random donor-acceptor-donor-acceptor molecular configuration, with the physicochemical properties fine-tuned by adjusting the feed ratio of co-monomers. Photodiode devices exhibited strong absorption and low surface roughness, with the 1:2 blending ratio identified as the optimal combination for maximum charge photogeneration efficiency.
Article
Polymer Science
Stefania Aivali, Peisen Yuan, Julianna Panidi, Dimitra G. Georgiadou, Themis Prodromakis, Joannis K. Kallitsis, Panagiotis E. Keivanidis, Aikaterini K. Andreopoulou
Summary: A route towards processable n-type terpolymers based on the random donor-acceptor-donor-acceptor (D-A1)-(D-A2) molecular configuration is presented. The physicochemical properties of the terpolymers are fine-tuned based on the feed ratio of the co-monomers. Photodiode devices using the rich in PDI terpolymer showed good performance.
Article
Polymer Science
Daisuke Hotta, Arihiro Kanazawa, Sadahito Aoshima
Summary: tert-Butyl esters play a crucial role as chain transfer agents in the cationic copolymerization, liberating tert-butyl cations to facilitate the chain transfer process. The chain transfer reactions by tert-butyl esters potentially occur reversibly through the reaction of the propagating cation with the ester group at the omega-end of another chain.
MACROMOLECULAR RAPID COMMUNICATIONS
(2021)
Article
Polymer Science
Keisuke Hayashi, Arihiro Kanazawa, Sadahito Aoshima
Summary: This study presents a novel approach using o-phthalaldehyde (OPA) as a comonomer to enable the cationic copolymerization of various bulky enol ethers that are difficult to homopolymerize and/or copolymerize. The relationships between the structures of the enol ethers and the copolymerization behavior were investigated, revealing that monomers with methyl and/or primary alkyl groups can undergo alternating copolymerization with OPA.
Article
Polymer Science
Kazuya Maruyama, Arihiro Kanazawa, Sadahito Aoshima
Summary: A one-pot synthesis method was developed for the controllable synthesis of ABC-type periodic terpolymers. The method involved the sequential-programmed cyclic monomer synthesis and living cationic copolymerization. The terpolymers exhibited controlled molecular weights, periodic sequence, molecular weight distribution, and chain ends. Additionally, the terpolymers could be degraded by acid. Furthermore, ABC-type sequence terpolymers and periodic block quaterpolymers were synthesized by the addition of different vinyl monomers.
Article
Polymer Science
Keisuke Hayashi, Arihiro Kanazawa, Sadahito Aoshima
Summary: The cationic copolymerization ofo-phthalaldehyde with various styrene derivatives and vinyl ethers was investigated, with a focus on the relationship between the structure and reactivity of vinyl monomers and the copolymerization behavior. The existence of alpha or beta-substituents on the vinyl group was found to be essential for efficient crossover reactions with styrene derivatives, while various vinyl ethers underwent copolymerization with o-phthalaldehyde. The use of vinyl monomers with both large steric hindrance and highly reactive beta-carbon was effective in achieving an alternating-like copolymerization. Additionally, degradable copolymers were successfully obtained from styrene derivatives.
Article
Polymer Science
Hironobu Watanabe, Arihiro Kanazawa, Satoshi Okumoto, Sadahito Aoshima
Summary: In the cationic polymerization of N-vinylcarbazole, the electronic properties of counteranions were found to be key in stereo-regulation. Fine-tuning the counteranions led to successful synthesis of stereo-designed polymers.
Article
Polymer Science
Kazuya Maruyama, Arihiro Kanazawa, Sadahito Aoshima
Summary: This study investigated the structural difference of cyclic acetals in cationic copolymerization with vinyl monomers, and found that the substituents of cyclic acetals significantly affected the electronic and steric environments around the carbocation generated in the propagation reaction, which in turn affected the frequency of crossover reactions. Acid hydrolysis of alternating copolymers resulted in complete degradation and selective generation of a single compound due to the periodic incorporation of acetal structures in the main chains.
Article
Polymer Science
Tomoki Nara, Arihiro Kanazawa, Sadahito Aoshima
Summary: The cationic copolymerizations of styrene derivatives and benzaldehyde were studied to achieve alternating copolymerization and create degradable polystyrene derivatives. The copolymerization of p-methylstyrene and benzaldehyde was found to proceed in a living manner with GaCl3 as a catalyst, producing a copolymer with an alternating sequence and controllable molecular weight. The copolymer exhibited the formation of sec-benzylic ether structures, leading to its degradation under acidic conditions.
Article
Polymer Science
Junichi Azuma, Arihiro Kanazawa, Sadahito Aoshima
Summary: Vinyl acetate (VAc) exhibits cationic polymerizability and can react with suitable comonomers to produce alternating copolymers or branched copolymers. Detailed analysis of the polymerization products can reveal the mechanisms of these copolymerization reactions.
Article
Polymer Science
Arihiro Kanazawa, Sadahito Aoshima, Ryosuke Hada
Summary: Polymers with silyl ether moieties have attracted significant interest due to their properties derived from silicon-oxygen linkages and acid-, base-, and fluoride ion-triggered degradability. In this study, 1,3-dioxa-2-silacycloalkanes were used as monomers for the synthesis of silyl ether polymers through cationic terpolymerization. The resulting terpolymers, which had ABC-type pseudo-periodic sequences, exhibited acid-, base-, or fluoride ion-triggered degradability and were degraded under acidic conditions.
Article
Polymer Science
Yuka Takahashi, Arihiro Kanazawa, Sadahito Aoshima
Summary: 3-Alkoxyphthalides (ROPTs) are candidate monomers that react with cationic species to generate oxocarbenium ions. This study focused on the cationic polymerization of ROPTs with oxiranes, and found that homopolymerization did not occur, while copolymerization with oxiranes proceeded smoothly. Copolymer degradation under acidic conditions was observed due to acetal cleavage from ROPT to oxirane. The successful terpolymerization of VE, oxirane, and ROPT resulted in ABC-type pseudo-periodic terpolymers under optimized conditions.
Article
Polymer Science
Kazuya Maruyama, Arihiro Kanazawa, Sadahito Aoshima
Summary: This study demonstrated the synthesis of sequence-controlled copolymers with controllable molecular weights and chain ends composed of alcohols, cyclic enol ethers, and vinyl ethers. The synthesis was achieved through selective monomer generation and subsequent alternating copolymerization. The copolymers obtained had periodically arranged alcohol-derived side chain-containing cyclic enol ether and VE moieties in the repeating units, confirmed by complete degradation into a single compound by alcoholysis. The use of specific alcohols was found to be effective for the synthesis of well-defined polymers.
Article
Chemistry, Multidisciplinary
Tadashi Naito, Arihiro Kanazawa, Sadahito Aoshima
Summary: ABAC-type periodic polymer, Poly(cyclic acetal)s, were synthesized via a two-step method and exhibited different degradation behaviors under acidic conditions.
Article
Polymer Science
Kana Takebayashi, Arihiro Kanazawa, Sadahito Aoshima
Summary: The cationic ring-opening copolymerization of cyclic acetals and 1,3-dioxolan-4-ones (DOLOs) was investigated, with a focus on understanding the polymerization mechanisms. The copolymerization of 1,3-dioxepane and 5-methyl-1,3-dioxolan-4-one successfully occurred using CF3SO3H as a catalyst, resulting in high molecular weight copolymers. NMR spectrometry and electrospray ionization mass spectrometry were used to analyze the detailed structure of the copolymers, which indicated that the copolymerization proceeds through an activated monomer mechanism involving the reaction of a hydroxy group and a proton-attached DOLO. Acid-catalyzed transacetalization reactions also likely occurred during the copolymerization process.
Article
Polymer Science
Tadashi Naito, Arihiro Kanazawa, Sadahito Aoshima
Summary: In this study, alternating cationic copolymerizations were investigated to obtain polymers with ABCC-type monomer sequences, which were prepared from the reaction of 2-chloroethyl vinyl ether (CEVE) and cyclic trimers. The kinds of vinyl monomers and aldehyde molecules incorporated into the cyclic trimers affected the copolymerization frequencies with CEVE, and a cyclic trimer consisting of isobutyl VE (IBVE) and 2-nonenal (NNE) showed highly effective alternating copolymerizations with CEVE at appropriate monomer concentrations. Structural analysis of the methanolysis products revealed mainly ABCC-type periodic sequences (83% under optimized conditions).
Article
Polymer Science
Tadashi Naito, Arihiro Kanazawa, Sadahito Aoshima
Summary: Tandem polymerization consisting of cyclotrimerization and the Tishchenko reaction using a catalyst mixture of EtAlCl2 and Al(OiPr)(3) was demonstrated. The optimized conditions resulted in polymers with different molecular weights and structures, including cyclic acetal and ester structures. The initial molar ratio of the catalyst mixture influenced the reaction frequency, and cyclic oligomers could be selectively hydrolyzed under acidic or alkaline conditions.