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
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
Maksim Hulnik, Diana Trofimuk, Pavel A. A. Nikishau, Huseyin Cem Kiliclar, Baris Kiskan, Sergei V. V. Kostjuk
Summary: The visible-light-induced cationic polymerization of isobutylene was achieved using a Mn-2(CO)(10)/Ph2I+PF6(-) photoinitiating system. The polymerization was initiated by chloromethylisobutyl carbocations generated from the oxidation of chloromethylisobutyl radicals by Ph2I+PF6(-). This system allowed the synthesis of low molecular weight polyisobutylene with a low polydispersity and a high content of exo-olefin end groups.
Article
Polymer Science
Ling Cai, Qi-Yuan Wang, Xin-Li Liu, Dong-Mei Cui
Summary: In this study, cationic polymerization of isobutylene was achieved under mild conditions using a new binary initiation system. The generated acidic coordinating complex was found to be the initiating active species, which transformed into active intermediates stabilized by coordination with a counter anion.
CHINESE JOURNAL OF POLYMER SCIENCE
(2023)
Article
Polymer Science
Ryoya Kamiki, Tomohiro Kubo, Kotaro Satoh
Summary: This study aims to synthesize novel degradable polymers by copolymerizing bio-based thiocarbonyl compounds with various vinyl monomers using radical addition-fragmentation ring-opening reaction. The obtained polymers have degradable functional groups that can be cleaved under specific conditions with different chemical stimuli.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Veronika Kottisch, Janis Jermaks, Joe-Yee Mak, Ryan A. Woltornist, Tristan H. Lambert, Brett P. Fors
Summary: The novel hydrogen bond donor-organic acid pair facilitates controlled cationic polymerization of vinyl ethers at ambient conditions, allowing for rapid synthesis of high-molecular-weight poly(vinyl ethers).
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Polymer Science
Ke Yang, Qiang Liu, Shuai Wen, Tao Zhuang
Summary: Branched polyisobutylenes with low dispersities and benzylic halide functionalities were synthesized by self-condensing vinyl cationic copolymerization. However, challenges remain in obtaining high molecular weight branched polyisobutylenes through this method.
JOURNAL OF POLYMER SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Michael J. Supej, Elizabeth A. McLoughlin, Jesse H. Hsu, Brett P. Fors
Summary: Advancements in externally controlled polymerization methodologies have enabled the synthesis of novel polymeric structures and architectures, with a particular focus on the development of ring-opening polymerization methods for biocompatible and biodegradable block polymers. The use of ferrocene-derived acid catalysts with reversible acidity control shows promise for chemically and electrochemically controlling the ROP of cyclic esters.
Article
Polymer Science
Francisco J. Arraez, Xiaowen Xu, Mariya Edeleva, Paul H. M. Van Steenberge, Yoshi W. Marien, Valentin-Victor Jerca, Richard Hoogenboom, Dagmar R. D'hooge
Summary: Cationic ring-opening polymerization (CROP) is an interesting synthesis technique for obtaining well-defined polymers with narrow molar mass distribution. By combining experimental data recording and kinetic Monte Carlo modeling, a detailed understanding of the relationship between reaction conditions and molecular properties of poly(2-oxazoline)s (PAOx) can be obtained for optimization of the synthesis of well-defined PAOx building blocks. The validated model provides insights into the type of macrospecies present and allows differentiation between different coupling reactions.
Article
Polymer Science
Xia Lin, Jiajia Li, Jiandong Zhang, Shaoxiang Liu, Xiaofang Lin, Xiangqiang Pan, Jian Zhu, Xiulin Zhu
Summary: A living cationic polymerization of vinyl ethers was developed using electrophilic selenium reagents as initiators and pentacarbonylbromomanganese as the catalyst. This polymerization could be conducted under ambient conditions and yielded polymers with controlled molecular weights and narrow molecular weight distributions. The method also allowed for the introduction of different selenium-containing structures into the polymers.
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
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
Chemistry, Applied
Yangyang Xin, Shizhuo Xiao, Yulian Pang, Yingquan Zou
Summary: This paper investigates the use of Near-Infrared sensitizer induced Radical Induced Cationic frontal polymerization (RICFP) in vinyl ethers and epoxides. It was found that vinyl ethers exhibited higher reactivity and conversion rates compared to other cationic polymerizable monomers. The study also explored the use of a three-component system with NIR sensitizer, iodonium salt, and thermal initiator in RICFP.
PROGRESS IN ORGANIC COATINGS
(2021)
Article
Chemistry, Multidisciplinary
Xun Zhang, Zan Yang, Yu Jiang, Saihu Liao
Summary: Tacticity plays a crucial role in determining the properties of synthetic polymer materials. In this study, a new chiral organic Brønsted acid catalyst was introduced for the cationic polymerization of vinyl ethers, leading to highly stereoselective polymerization reactions. This innovative approach not only produces high-quality isotactic poly(vinyl ethers), but also allows for chain extension to synthesize diblock copolymers.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Xun Zhang, Zan Yang, Yu Jiang, Saihu Liao
Summary: A new chiral organic Bronsted acid catalyst, PADIs, enables highly stereoselective cationic polymerization of vinyl ethers without the need for metal catalysts. This process produces isotactic poly(vinyl ethers) with controllable molecular mass and narrow dispersity. Additionally, the use of trithiocarbonate chain-transfer agent allows for chain extension and synthesis of diblock copolymers containing isotactic poly(vinyl ether) blocks through a mechanism switch.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
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.
