Akikazu Matsumoto

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Name:

Organization: Osaka Prefecture University , Japan

Department: Department of Applied Chemistry

Title: Professor(PhD)

TOPICS

Polymer

Atom Transfer Radical Polymerization Radical Polymerization RAFT Block Copolymer

Organic Chemistry

Liquid Crystal

Chemicals
References

Thermal and mechanical properties of random copolymers of diisopropyl fumarate with 1-adamantyl and bornyl acrylates with high glass transition temperatures

Co-reporter:

Journal of Polymer Science Part A: Polymer Chemistry 2017 Volume 55(Issue 2) pp:288-296

Publication Date(Web):2017/01/15

DOI:10.1002/pola.28381

ABSTRACTWe report the thermal, optical, and mechanical properties of random copolymers produced by radical copolymerizations of diisopropyl fumarate (DiPF) with 1-adamantyl acrylate (AdA) and bornyl acrylate (BoA). The effects of a methylene spacer included in the main chain and bulky ester alkyl groups in the side chain on the copolymer properties are discussed. The produced copolymers are characterized by NMR and UV–vis spectroscopies, size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis (DMA). The copolymerization rate and the molecular weight of the copolymers increase with an increase in the acrylate content in feed during the copolymerization (Mw = 25–110 × 103). The onset temperature of decomposition (Td5) and the glass transition temperature (Tg) of the copolymers also increase according to the content of the acrylate units (Td5 = 296–329 °C and 281–322 °C, Tg = 80–133 °C and 91–106 °C for the copolymers of DiPF with AdA and BoA, respectively). Transparent and flexible copolymer films are obtained by a casting method and their optical properties such as transparency and refractive indices are investigated (nD = 1.478–1.479). The viscoelastic data of the copolymers are collected by DMA measurements under temperature control. The storage modulus decreases at a temperature region over the Tg value of the copolymers, depending on the structure and amount of the acrylate units. The sequence structure of the copolymers is analyzed based on monomer reactivity ratios and composition in order to discuss the copolymer properties related to chain rigidity and sequence length distribution. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 288–296

UV and γ-ray resistance of poly(N-methylmaleimide-alt-isobutene) and poly(diisopropyl fumarate) as transparent polymer films

Co-reporter:Ryota Imaizumi, Masakazu Furuta, Haruyuki Okamura, Akikazu Matsumoto

Radiation Physics and Chemistry 2017 Volume 138(Volume 138) pp:

Publication Date(Web):1 September 2017

DOI:10.1016/j.radphyschem.2017.04.018

•UV- and γ-resistance of PMI and PDiPF as transparent polymers was investigated.•UV- and γ-radiations induced the chain scission and crosslinking of these polymers.•γ-radiation resulted in significant changes in structure and properties of the polymers.•Degradation mechanism of PMI and DiPF was discussed.UV and γ-ray resistance of transparent polymers obtained by radical polymerization of maleic and fumaric acid derivatives, i.e., an alternating copolymer of N-methylmaleimide and isobutene (PMI) and poly(diisopropyl fumarate) (PDiPF), was investigated. Transmittance in UV and visible regions of these polymers were examined after UV irradiation and compared with the results for poly(methyl methacrylate) (PMMA) and polycarbonate (PC) as conventional transparent polymers. The order of stability toward UV irradiation was PMMA≈PDiPF>PMI>>PC, deduced from changes in the transmittance of 380 nm light. Tensile mechanical properties, such as elastic modulus, maximum strength, and elongation values of PMI, PDiPF, and PMMA were also investigated after UV and γ-radiation. UV irradiation induced the side chain scission of PMI and PDiPF via Norrish I type reaction as well as crosslinking by combination between formed polymer radicals, leading to deterioration in their optical and mechanical properties. γ-radiation induced significant changes in molecular weight and mechanical properties of the polymers. In conclusion, PMI exhibited unchanged mechanical properties and PDiPF maintained its high transparency under various irradiation conditions.

Living radical polymerization of diisopropyl fumarate to obtain block copolymers containing rigid poly(substituted methylene) and flexible polyacrylate segments

Co-reporter:Akikazu Matsumoto;Naoki Maeo;Eriko Sato

Journal of Polymer Science Part A: Polymer Chemistry 2016 Volume 54( Issue 14) pp:2136-2147

Publication Date(Web):

DOI:10.1002/pola.28081

ABSTRACT

Living radical polymerizations of diisopropyl fumarate (DiPF) are carried out to synthesize poly(diisopropyl fumarate) (PDiPF) as a rigid poly(substituted methylene) and its block copolymers combined with a flexible polyacrylate segment. Reversible addition-fragmentation chain transfer (RAFT) polymerization is suitable to obtain a high-molecular-weight PDiPF with well-controlled molecular weight, molecular weight distribution, and chain-end structures, while organotellurium-mediated living radical polymerization (TERP) and reversible chain transfer catalyzed polymerization (RTCP) give PDiPF with controlled chain structures under limited polymerization conditions. In contrast, controlled polymerization for the production of high-molecular-weight and well-defined PDiPF is not achieved by atom transfer radical polymerization (ATRP) and nitroxide-mediated radical polymerization (NMP). The block copolymers consisting of rigid poly(substituted methylene) and flexible polyacrylate segments are synthesized by the RAFT polymerization. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2136–2147

Crosslinking and ozone degradation of thermosetting resins based on maleic anhydride/diene copolymer and polyfunctional alcohols

Co-reporter:Limin Lou;Mika Nagashima;Haruyuki Okamura

Journal of Applied Polymer Science 2015 Volume 132( Issue 45) pp:

Publication Date(Web):

DOI:10.1002/app.42763

ABSTRACT

Crosslinking and de-crosslinking reactions of an alternating copolymer of maleic anhydride (MAn) and 2,4-dimethyl-1,3-pentadiene (DMPD) by thermal curing with polyfunctional alcohols as the crosslinkers and subsequent ozone degradation are reported in this article. The ring-opening reaction of an anhydride group by polyfunctional alcohols produces network polymers with an ester linkage. The rate of crosslinking reaction depends on the curing conditions, i.e. the structure of the used alcohols and the curing temperature and time. The crosslinking density of the alcohol-cured copolymers is low due to a slow reaction between the anhydride and hydroxy groups, being different from the corresponding epoxy-cured copolymer with a dense network structure reported in a previous article. The insoluble resins are readily de-crosslinked and solubilized by ozone degradation. The polymer surface modification by ozone is also investigated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42763.

Acetal-protected acrylic copolymers for dismantlable adhesives with spontaneous and complete removability

Co-reporter:Eriko Sato, Keisuke Yamanishi, Tadashi Inui, Hideo Horibe, Akikazu Matsumoto

Polymer 2015 Volume 64() pp:260-267

Publication Date(Web):1 May 2015

DOI:10.1016/j.polymer.2015.01.057

•The copolymers were investigated as dismantlable pressure-sensitive adhesives.•The copolymers underwent deprotection and cross-linking by external stimuli.•The reactions of the copolymers induced a decrease in 180° peel strength.•The effects of the copolymer compositions on dismantlability were revealed.•Spontaneous and complete removal of the adhesive layer were achieved.Acetal-protected acrylic copolymers consisting of 1-isobutoxyethyl acrylate (iBEA), 2-ethylhexyl acrylate (2EHA), and 2-hydroxyethyl acrylate (HEA) repeating units were applied to the pressure-sensitive adhesive (PSA) types of dismantlable adhesives. The random and block copolymers with a relatively high HEA content showed good PSA properties before dismantling treatment. The deprotection of the acetal-protected group of the iBEA unit took place in response to individual external stimuli, soaking in boiling water and UV irradiation in the presence of a photoacid generator. The random copolymers containing an HEA unit of more than 10 mol% and an iBEA unit of more than 70 mol% achieved spontaneous debonding with interfacial failures at both the stainless steel and polyethylene terephthalate support film sides by soaking in boiling water within 10 min, whereas the corresponding block copolymer did not achieve interfacial failure even after a 20-min soaking. Photoirradiation of the random copolymers containing N-hydroxynaphthalimide triflate as a photoacid generator resulted in interfacial failures at both sides with a sufficiently reduced peel strength, where cross-linking arose due to the transacetalization and transesterification of a hydroxy group in the HEA unit along with deprotection.

Molecular design of diene monomers containing an ester functional group for the synthesis of poly(diene sulfone)s by radical alternating copolymerization with sulfur dioxide

Co-reporter:Akikazu Matsumoto;Sungi Lee;Haruyuki Okamura

Journal of Polymer Science Part A: Polymer Chemistry 2015 Volume 53( Issue 8) pp:1000-1009

Publication Date(Web):

DOI:10.1002/pola.27528

ABSTRACT

Functional poly(diene sulfone)s are prepared by the radical alternating copolymerization of 1,3-diene monomers containing an ester substituent with sulfur dioxide. Methyl 3,5-hexadienoate (MH) and methyl 5,7-octadienoate (MO) with both an alkylene spacer and a terminal diene structure are suitable to produce a high-molecular-weight copolymer in a high yield, while the copolymerization of 5,7-nonadienoic acid, ethyl 2,4-pentadienoate, and ethyl 4-methyl-2,4-pentadienoate including either an alkylene spacer or a terminal diene structure lead to unsuccessful results. The ¹³C NMR chemical shift values of MH and MO suggest a high electron density at their reacting α-carbon for exhibiting a high copolymerization reactivity. Fluorene-containing diene monomers, 9-fluorenyl 3,5-hexadienoate (FH) and 9-fluorenyl 5,7-octadienoate (FO), are also prepared and copolymerized with sulfur dioxide. The thermal and optical properties of the poly(diene sulfone)s containing the methyl and fluorenyl ester substituents in the side chain are investigated. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1000–1009

High-molecular-weight polar acrylate block copolymers as high-performance dismantlable adhesive materials in response to photoirradiation and postbaking

Co-reporter:Tadashi Inui, Eriko Sato and Akikazu Matsumoto

RSC Advances 2014 vol. 4(Issue 47) pp:24719-24728

Publication Date(Web):14 May 2014

DOI:10.1039/C4RA03745F

We synthesized high-molecular-weight acrylate block copolymers as high-performance dismantlable adhesives consisting of a poly(tert-butyl acrylate) (PtBA) sequence as the reactive segment and a random copolymer sequence of n-butyl acrylate (nBA) or 2-ethylhexyl acrylate (2EHA) with 2-hydroxyethyl acrylate (HEA) as the adhesive segment, using an organotellurium-mediated living radical polymerization (TERP). The adhesion strength of PtBA/P2EHA and PtBA/PnBA block copolymers containing polar HEA repeating units in their soft segments was sufficiently high for use as a pressure-sensitive adhesive. A quick change in the adhesion properties was observed in response to the dual external stimuli of photoirradiation and postbaking during the dismantling process. We discuss the adhesion strength and failure mode as a function of the HEA content, the sequence structure of the copolymers, and the external stimulus conditions.

Radical Alternating Copolymerization of Twisted 1,3-Butadienes with Maleic Anhydride as a New Approach for Degradable Thermosetting Resin

Co-reporter:Asuka Tsujii, Mami Namba, Haruyuki Okamura, and Akikazu Matsumoto

Macromolecules 2014 Volume 47(Issue 19) pp:6619-6626

Publication Date(Web):September 29, 2014

DOI:10.1021/ma501555n

We report a novel approach for the synthesis of a readily curable and degradable resin by the radical alternating copolymerization of 1,3-diene monomers with maleic anhydride. 2,4-Dimethyl-1,3-pentadiene predominantly produced an alternating copolymer rather than a Diels–Alder adduct during the reaction with maleic anhydride. We revealed the most stable conformation as a twisted diene structure of 2,4-dimethyl-1,3-pentadiene and the other methyl-substituted dienes by DFT calculations, while a completely planar structure was preferred for the s-cis and s-trans conformers of the nonsubstituted butadiene. The highly alternating repeating structure of the produced copolymers was revealed based on the NMR analysis and copolymerization reactivity ratios. The alternating copolymers including an anhydride moiety and a carbon-to-carbon double bond in each repeating unit was conveniently used for the thermosetting, subsequent degradation, and polymer–surface modification by postpolymerization reactions such as epoxy curing and oxidative ozonolysis.

Synthesis and thermal, optical, and mechanical properties of sequence-controlled poly(1-adamantyl acrylate)-block-poly(n-butyl acrylate) containing polar side group

Co-reporter:Yoshinori Nakano;Eriko Sato

Journal of Polymer Science Part A: Polymer Chemistry 2014 Volume 52( Issue 20) pp:2899-2910

Publication Date(Web):

DOI:10.1002/pola.27322

ABSTRACT

We prepared the sequence-controlled block copolymers including poly(1-adamantyl acrylate) (PAdA) and poly(n-butyl acrylate) sequences as the hard and soft segments, respectively, by the organotellurium-mediated living radical polymerization. The thermal, optical, and mechanical properties of the adamantane-containing block copolymers with polar 2-hydroxyethyl acrylate (HEA) and acrylic acid (AA) repeating units were investigated. The microphase-separated structures of the block copolymers were confirmed by the differential scanning calorimetry and atomic force microscopy observations as well as dynamic mechanical measurements. The α- and β-dispersions due to the main-chain and side group molecular motions, respectively, of the hard and soft segments were observed. Their transition temperatures and activation energies increased due to the formation of intermolecular hydrogen bonding by the introduction of the HEA and AA repeating units. The effects of the hydrogen bonding on their tensile elasticity, strength, and strain were also evaluated. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2899–2910

Synthesis and Thermal Properties of Comb-Like Maleimide Copolymers Containing Polymethylene and Poly(Ethylene Oxide) Side Chains as the N-Substituents

Co-reporter:Kyota Takeda;Akitoshi Omayu

Macromolecular Chemistry and Physics 2013 Volume 214( Issue 18) pp:2091-2098

Publication Date(Web):

DOI:10.1002/macp.201300331

Radical Copolymerization Reactivity of N-Substituted Maleimides with -Substituted Styrenes with Various N- and -Substituents and the Thermal and Optical Properties of the Resulting Copolymers

Co-reporter:Miki Hisano;Tsutomu Takashima;Zhengzhe Jin;Akira Shiibashi

Macromolecular Chemistry and Physics 2013 Volume 214( Issue 14) pp:1612-1620

Publication Date(Web):

DOI:10.1002/macp.201300228

Sequence-Controlled Radical Copolymerization of N-Substituted Maleimides with Olefins and Polyisobutene Macromonomers To Fabricate Thermally Stable and Transparent Maleimide Copolymers with Tunable Glass Transition Temperatures and Viscoelastic Properties

Co-reporter:Miki Hisano, Kyota Takeda, Tsutomu Takashima, Zhengzhe Jin, Akira Shiibashi, and Akikazu Matsumoto

Macromolecules 2013 Volume 46(Issue 19) pp:7733-7744

Publication Date(Web):September 20, 2013

DOI:10.1021/ma401499v

Thermally stable and transparent polymers were synthesized by the sequence-controlled radical copolymerization of N-substituted maleimides (RMIs) with various olefins as well as polyisobutene (PIB) macromonomers. The copolymerization behavior significantly depended on the olefin structures, leading to the formation of AB-alternating and AAB-periodic (2:1 sequence-controlled) copolymers. The sequence-controlled radical copolymerization mechanism was discussed based on the monomer reactivity ratios, which were determined using terminal and penultimate unit models for the copolymerization systems investigated in this study as well as in the literature. The olefin comonomers were classified into several groups according to the copolymerization fashions under the terminal and penultimate unit controls and their conjugated structure and the steric bulkiness of the substituents. The copolymers exhibited excellent thermal properties; the onset temperatures of the resulting copolymers were higher than 300 °C, and the glass transition temperature (Tg) values varied over the temperature range of −68 to 210 °C, depending on the structure of the N- and α-substituents of the comonomer repeating units. The introduction of sterically hindered substituents increased the Tg values, while the introduction of the PIB segments as the side chain of the copolymers resulted in a significant decrease in the Tg value and unique fluidity. The optical and viscoelastic properties of the high-Tg copolymers were investigated.

Organotellurium-Mediated Living Radical Polymerization (TERP) of Acrylates Using Ditelluride Compounds and Binary Azo Initiators for the Synthesis of High-Performance Adhesive Block Copolymers for On-Demand Dismantlable Adhesion

Co-reporter:Tadashi Inui, Keisuke Yamanishi, Eriko Sato, and Akikazu Matsumoto

Macromolecules 2013 Volume 46(Issue 20) pp:8111-8120

Publication Date(Web):September 30, 2013

DOI:10.1021/ma401595w

We report the organotellurium-mediated living radical polymerization (TERP) using diphenylditelluride (DT-Ph) and di-n-butylditelluride (DT-Bu) in the presence of a binary azo initiator system consisting of 2,2′-azobis(isobutyronitrile) (AIBN) and 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) (AMVN) with different decomposition rates for the facile synthesis of high-molecular-weight block copolymers containing a polar side group. The block copolymers containing the poly(tert-butyl acrylate) (PtBA) sequence as the reactive segment and the random copolymer sequences of n-butyl acrylate (nBA) or 2-ethylhexyl acrylate (2EHA) with 2-hydroxyethyl acrylate (HEA) as the adhesive segment were synthesized. The concurrent use of the binary initiators was revealed to effectively increase both the polymerization reactivity and the molecular weight of the polymers along with a narrow molecular weight distribution. The produced block copolymers exhibited high performance for the dismantlable adhesion responsible for the dual external stimuli consisting of photoirradiation and postbaking in the presence of a photoacid generator.

Controlled Radical Polymerization of 3-Methylenecyclopentene with N-Substituted Maleimides To Yield Highly Alternating and Regiospecific Copolymers

Co-reporter:Daisuke Yamamoto and Akikazu Matsumoto

Macromolecules 2013 Volume 46(Issue 24) pp:9526-9536

Publication Date(Web):December 12, 2013

DOI:10.1021/ma4020092

High-molecular-weight diene copolymers with a regiospecific repeating structure were produced in a high yield during the alternating radical copolymerization of N-substituted maleimides (RMIs) and 3-methylenecyclopentene (MCP) as the cyclic 1,3-diene monomer including a reactive exomethylene moiety. The eminent copolymerization reactivity of MCP was in contrast to the predominant occurrence of the Diels–Alder reaction of isoprene with the RMIs rather than copolymerization. The highly alternating structure of the copolymers was confirmed based on the monomer reactivity ratios for the copolymerization of MCP (M1) and N-phenylmaleimide (PhMI, M2), r1 = 0.010 and r2 = 0.0080. A mechanism for the highly controlled 1,4-regiospecific propagation, which consists of the addition of an RMI radical to the exomethylene group of MCP and subsequent 1,4-regiospecific propagation, was supported by the DFT calculations using model reactions as well as the precise structure determination of oligomers produced during telomerization in the presence of 1-butanethiol as a chain transfer agent. The resulting copolymers exhibited no weight-loss under 340 °C during heating in a nitrogen atmosphere and their glass transition temperature was over the wide temperature range of 66–159 °C, depending on the structure of the N-alkyl substituents. The transparent and flexible films were fabricated by a casting method. The optical properties of the films were as follows: the visible light transmittance over 95% at 380 nm, the refractive indices of 1.54–1.58, and the Abbe number of 42–45.