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Hatsuo Ishida - One of the best experts on this subject based on the ideXlab platform.
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Benzoxazine Chemistry in Solution and Melt
Handbook of Benzoxazine Resins, 2020Co-Authors: Hatsuo IshidaAbstract:Publisher Summary Benzoxazine synthesis and its chemical reactions with specific interest in polymerizing them are reviewed in this chapter. The very rich molecular design flexibility offers tremendous opportunity to design Benzoxazine resins that allows tailoring the polyBenzoxazine properties. The complex reaction occurring during the synthesis of the monomers and polymerization makes studies of Benzoxazine complex. Progress is made from a controlled, laboratory synthesis of Benzoxazines in homogeneous solutions at modest to low concentrations to more high solid and/or melt systems that are much more efficient for scale-up synthesis. It explains that difunctional Benzoxazines are also prepared from various combinations of difunctional primary amines and monofunctional phenols or difunctional phenols as well as polyhydric phenols with monofunctional primary amines. Recent reports for synthesizing linear polymers with Benzoxazine structure in the main chain offer new opportunities in property tailoring, it is nonetheless the variation of this small molecular weight chemistry that was extended to difunctional phenolic and amine compounds. This chapter illustrates that polymers containing fluorinated aromatic systems often exhibit exceptional thermal stability. Decreased friction coefficient, refractive index, and dielectric constant are some of the well-known benefits of the fluorine introduction. It is difficult to introduce more than two halogen atoms into each aromatic ring in phenolic materials due to the restriction imposed by the traditional phenolic chemistry.
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Synthesis and ring-opening polymerization of 2-substituted 1,3-Benzoxazine: the first observation of the polymerization of oxazine ring-substituted Benzoxazines
Polymer Chemistry, 2020Co-Authors: Seishi Ohashi, Francis Cassidy, Stephanie Huang, Kevin Chiou, Hatsuo IshidaAbstract:2-Substituted 1,3-Benzoxazines (two Benzoxazine monomers used in this paper are abbreviated as PH-a-[2]ba and PH-pda-[2]ba) having a phenyl group as an oxazine ring substituent are synthesized with benzaldehyde through 2-hydroxy-N-phenylbenzylamine structures. The polymerization of these monomers is observed for the first time and confirmed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR). The poly(PH-a-[2]ba) derived from 2-substituted 1,3-Benzoxazines exhibits good thermal properties based on TGA analysis, despite showing slight inferiority to poly(PH-a), an unsubstituted counterpart of PH-a-[2]ba. Additionally, benzylideneaniline is extracted during the polymerization, indicating that this compound is the byproduct of the polymerization mechanism. Structural verification is achieved by synthesizing benzylideneaniline and comparing its 1H-NMR spectrum with the reaction byproduct.
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Poly(Benzoxazine-f-chitosan) films: The role of aldehyde neighboring groups on chemical interaction of Benzoxazine precursors with chitosan
Carbohydrate Polymers, 2019Co-Authors: Almahdi A. Alhwaige, Hatsuo Ishida, Syed QutubuddinAbstract:Abstract This study reports the preparation and characterizations of chitosan-azomethine derivatives containing oxazine ring as new crosslinked polymers. The novel chitosan derivatives have been prepared by functionalization with reactive Benzoxazine precursors. Two types of aldehyde-terminated Benzoxazine precursors have been synthesized using two different polyetheramines (Jeffamines), 4-hydroxybenzaldehyde, and paraformaldehyde. The Benzoxazine precursors are covalently attached to chitosan via Schiff’s base formation. Benzoxazine structure is confirmed by proton nuclear magnetic resonance spectroscopy (1H-NMR) and Fourier transform infrared spectroscopy (FT-IR), whereas the imine-linkage formation is confirmed by FT-IR. The Benzoxazine-f-chitosan films are crosslinked by cationic ring-opening polymerization of Benzoxazine. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are used to study the thermal behavior of the obtained films. Wettability behavior of the resulting films was studied by contact angle measurements and compared with wettability of the neat chitosan film.
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a smart latent catalyst containing o trifluoroacetamide functional Benzoxazine precursor for low temperature formation of very high performance polybenzoxazole with low dielectric constant and high thermal stability
Macromolecules, 2017Co-Authors: Kan Zhang, Pablo Froimowicz, Hatsuo IshidaAbstract:A novel difunctional Benzoxazine with o-trifluoroacetamide functionality has been synthesized via Mannich condensation. The chemical structure of synthesized monomer has also been confirmed by 1H, 13C, and 19F nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. The ring-opening polymerization of the resin and the subsequent conversion of the freshly generated polyBenzoxazine into polybenzoxazole are studied by FT-IR and differential scanning calorimetry (DSC). In addition to the advantage of low polymerization temperature as other reported o-amide Benzoxazines, the o-trifluoroacetamide Benzoxazine also exhibits an unexpected lower benzoxazole formation temperature. Furthermore, the resulting fluorinated polybenzoxazole derived from the Benzoxazine monomer possesses the combined excellent properties of facile synthesis, easy processability, low dielectric constant, high thermal stability, and long shelf life, evidencing its potential applications in microelect...
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Advanced and Emerging PolyBenzoxazine Science and Technology
Advanced and Emerging Polybenzoxazine Science and Technology, 2017Co-Authors: Hatsuo Ishida, Pablo FroimowiczAbstract:© 2017 Elsevier Inc. All rights reserved. Advanced and Emerging PolyBenzoxazine Science and Technology introduces advanced topics of Benzoxazine resins and polyBenzoxazines as presented through the collaboration of leading experts in the Benzoxazine community, representing the authoritative introduction to the subjects. Broad topics covered include the recent development and improved understanding of the subjects, including low temperature cure, aerogels and carbon aerogels, smart chemistry in fire retarding materials and coatings, metal containing Benzoxazines, rational design of advanced properties, and materials from natural renew. In the past twenty years, the number of papers on polyBenzoxazine has continuously increased at an exponential rate. During the past three years, the number of papers published is more than the previous 17 years combined. The material is now part of only a few successfully commercialized polymers in the past 35 years. Therefore, interest in this material in both academia and industry is very strong. Includes the latest advancements in Benzoxazine chemistry Describes advanced materials, such as aerogels, carbons, smart coatings, nanofibers, and shape memory materials Includes additional characterization data and techniques, such as FT-IR, Raman, NMR, DSC, and TGA analyses.
Tarek Agag - One of the best experts on this subject based on the ideXlab platform.
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polymerization behavior of methylol functional Benzoxazine monomer
Reactive & Functional Polymers, 2013Co-Authors: Mohamed Baqar, Tarek Agag, Hatsuo Ishida, Syed QutubuddinAbstract:Abstract This study focuses on methylol functional Benzoxazines as precursors to build a network structure utilizing both Benzoxazine and resole chemistry. The first part is a review of systems that contain methylol groups which play a role on their crosslinking formation. The polymerization mechanism and properties of resoles will be highlighted as the most abundant polymers that are characterized by polymerization through condensation reaction of methylol group. In the second part, the effect of incorporating methylol group into Benzoxazine monomers is studied. Differential scanning calorimetry (DSC) is used to study the effect of methylol group on the rate of polymerization. Kissinger and Ozawa methods using non-isothermal DSC at different heating rates show that methylol monomer exhibits lower average activation energy compared to the un-functionalized monomer. The effect of adding catalysts into the monomers is also studied. p -Toluene sulfonic acid (PTSA) is found to be more efficient than 1-methyl-imidazole (IMD) and lithium iodide (LiI) in the case of methylol monomer due to its ability of accelerating both the methylol condensation and ring-opening polymerization. Additionally, thermal behavior of the monomers is studied using thermogravimetric analysis (TGA).
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benzoxazole resin a novel class of thermoset polymer via smart Benzoxazine resin
Macromolecules, 2012Co-Authors: Tarek Agag, Jia Liu, Robert Graf, Hans Wolfgang Spiess, Hatsuo IshidaAbstract:Among the wide list of known high performance polymers, polybenzoxazoles (PBOs) have gained a prominent position as the most heat-resistant polyheterocyclic polymer. Nonetheless, PBOs have found applications in a rather restricted variety of technologies, mainly in the form of fibers. Herein, we report our pioneering work for producing cross-linked polybenzoxazole via a novel route using recently developed smart class of Benzoxazine resins as precursors. This class of Benzoxazines incorporates multiple smart features all in one molecule. The most attractive feature is its structural transformation into a more thermally stable cross-linked polybenzoxazole without the harmful consequences of traditional polybenzoxazole synthesis, such as the use of poly(phosphoric acid) as solvent. By this smart conversion, the flame-retardant oxazole moieties are successfully incorporated into the network structure. Further advantages of this new route for cross-linked polybenzoxazoles include outstanding flexibility in mo...
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Mechanistic Pathways for the Polymerization of Methylol-Functional Benzoxazine Monomers
Macromolecules, 2012Co-Authors: Mohamed Baqar, Tarek Agag, Syed Qutubuddin, Rongzhi Huang, Joao Maia, Hatsuo IshidaAbstract:The polymerization mechanism of methylol-functional Benzoxazine monomers is reported using a series of monofunctional Benzoxazine monomers synthesized via a condensation reaction of ortho-, meta-, or para-methylol–phenol, aniline, and paraformaldehyde following the traditional route of Benzoxazine synthesis. A phenol/aniline-type monofunctional Benzoxazine monomer has been synthesized as a control. The structures of the synthesized monomers have been confirmed by 1H NMR and FT-IR. The polymerization behavior of methylol monomers is studied by DSC and shows an exothermic peak associated with condensation reaction of methylol groups and ring-opening polymerization of Benzoxazine at a lower temperature range than the control monomer. The presence of methylol group accelerates the ring-opening polymerization to give the ascending order of para-, meta-, and ortho-positions in comparison to the unfunctionalized monomer. Furthermore, rheological measurements show that the position of methylol group relative to b...
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methacryloyl functional Benzoxazine photopolymerization and thermally activated polymerization
Macromolecules, 2011Co-Authors: Tarek Agag, Yusuf Yagci, Hatsuo IshidaAbstract:A novel class of photopolymerizable Benzoxazines has been developed. This class has been coined as methacryloyl-functional Benzoxazines. It has been synthesized by the reaction of the new Benzoxazine monomers: (3-phenyl-3,4-dihydro-2H-benzo[e][1,3]oxazin-6-yl)methanol and methacryloyl chloride. The structure of the monomer has been confirmed by Fourier transform infrared spectroscopy (FTIR) and 1H and 13C nuclear magnetic resonance spectroscopy (NMR). Its photopolymerization has been successfully carried out with and without photoinitiator, while the thermally activated polymerization is compromised by low temperature degradation.
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poly Benzoxazine co urethane s a new concept for phenolic urethane copolymers via one pot method
Polymer, 2011Co-Authors: Mohamed Baqar, Tarek Agag, Hatsuo Ishida, Syed QutubuddinAbstract:Historically, applications for traditional phenolic resin/polyurethane materials are limited due to the inherently weak thermal stability of urethane-phenolic linkage and slow reaction rate. A novel concept has been developed to produce phenolic resin/polyurethane copolymers via Benzoxazine chemistry. Through one-pot synthesis, a series of linear poly(Benzoxazine-co-urethane) materials has been synthesized via the reaction of a newly developed dimethylol functional Benzoxazine monomer with 4,4′-methylene diphenyl diisocyanate and poly(1,4-butyleneadipate). The structure of the copolymers has been characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The copolymers in the film forms have been further thermally treated for crosslinking to produce crosslinked poly(Benzoxazine-co-urethane) via the ring opening polymerization of cyclic Benzoxazine moieties in the main-chain. The tensile properties of the films have been studied and compared with those of traditional high performance materials. The thermal properties of the crosslinked copolymers have also been studied by dynamic mechanical analysis, and thermogravimetric analysis (TGA).
Yusuf Yagci - One of the best experts on this subject based on the ideXlab platform.
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Benzoxazine resins as smart materials and future perspectives
Thermosets, 2020Co-Authors: Baris Kiskan, Yusuf YagciAbstract:Abstract PolyBenzoxazines are high-performance thermosets having a range of properties and capability to overcome drawbacks of traditional resole- and novolac-type phenolics. They exhibit low water absorption, high T g , high char yield, flame resistance, low shrinkage, and also limited or no release of by-products during curing, and they have comparable mechanical performance with bismaleimide resins. In this chapter, we provide an overview of polyBenzoxazines highlighting in the progress in the synthesis of both Benzoxazine monomers and polyBenzoxazine prepolymers, their resulting materials, and their composites. Moreover, industrially important Benzoxazines and current advances of Benzoxazine applications as smart materials ranging from self-healing materials to electroactive coatings were reviewed.
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Side- and End-Chain Benzoxazine Functional Polymers
Handbook of Benzoxazine Resins, 2020Co-Authors: Baris Kiskan, Yusuf YagciAbstract:Publisher Summary This chapter describes synthetic pathways for the synthesis of side- and end-chain Benzoxazine functional polymers by using controlled and conventional polymerization methods involving free radical and rhodium catalysts. It presents numerous synthetic methods to combine Benzoxazines with polymers and contribute to increase the performance and property characteristics of these resins. These approaches may serve a valuable guideline for preparing polyBenzoxazines with desired properties to fulfill industrial demands. The synthesis of the polyBenzoxazine by cross-linking bifunctional Benzoxazine monomer through a ring-opening reaction is reported and the benefits of this family of compounds are identified. PolyBenzoxazines can offer various superior properties compared to the conventional novolac or resole or epoxy type resins. Though Benzoxazine based materials possess several advantages, they are not very attractive to the chemical industry because of problems of processability, brittleness, and high curing temperatures. Recently a new type of addition-cure phenolic system, polyBenzoxazine is developed. These materials offer low water absorption, high char yield, resistance against flame, high modulus, high strength, high glass transition temperatures, chemical resistance, and long shelf life; they have very limited volumetric change upon curing; and strong acid catalysts are not required for curing. Though polyBenzoxazines have such superior properties, pure Benzoxazine based thermosettings suffer from high curing temperatures (200 °C or higher), difficulty in processing, and brittleness. Another encouraging approach is the synthesis of novel polymeric Benzoxazine precursors, designed to impart flexibility and processability. Incorporation of Benzoxazine groups into a polymer backbone as a side chain is an important way to obtain a dense network. Various synthetic methods can be used to obtain such kinds of precursors.
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Chapter 13 – Thiol-Benzoxazine Chemistry for Macromolecular Modifications
Advanced and Emerging Polybenzoxazine Science and Technology, 2020Co-Authors: Baris Kiskan, A. Musa, E. Semerci, Yusuf YagciAbstract:This chapter deals with the synthetic pathways of obtaining materials with thermally curable Benzoxazine moieties by using the catalytic opening of the lateral Benzoxazine rings by thiols (COLBERT), or in other words the thiol-Benzoxazine reaction to further improve special properties, particularly processibility and toughness or for designing new materials. The combination of COLBERT with photolytic thiol-ene, postpolymer modifications of main chain polyBenzoxazines, synthesis of linear, block copolymers, and hybrid networks are presented. The advantages of the thiol-Benzoxazine approach can be listed as fast and easy reaction conditions at ambient temperature or even below, 100% atom economy, and the availability of wide range of thiol compounds. Apart from these, the conventional benefits of Benzoxazine chemistry, like the ease of Benzoxazine synthesis and its design flexibility, can be considered additional virtues of thiol-Benzoxazine chemistry.
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Light-Induced Reactions of Benzoxazines and Derivatives
Handbook of Benzoxazine Resins, 2020Co-Authors: Mehmet Atilla Tasdelen, Baris Kiskan, Burcin Gacal, Fatmanur Kasapoglu, Luminita Cianga, Yusuf YagciAbstract:Publisher Summary This chapter describes photochemical routes for the incorporation of thermally polymerizable Benzoxazine in linear and cross-linked polymeric structures. It focuses on the use of both the free radical and cationic photoinitiating systems for Benzoxazine resins that provide some advantages or overcome existing problems and challenges in Benzoxazine chemistry. The photochemical degradation and UV stability of Benzoxazine resins are also discussed in this study. Benzoxazine resins are readily synthesized from Benzoxazine monomers, either monofunctional or of higher functionality. It elaborates that photoinitiated polymerization is an important industrial process widely used in different applications. This process induces the polymer formation with a fast transformation of the liquid monomer into a solid film with tailored physical chemical and mechanical properties. This is a striking advantage for both the classical polymerization of monofunctional monomers and modern curing applications. Photopolymerizations are simply polymerization reactions initiated by light, typically in the ultraviolet or visible region of the light spectrum. Photoinitiated polymerization can be divided into two categories: free radical and cationic polymerizations. Deep curing using the described photoinitiating system followed by the thermal ring-opening of the incorporated Benzoxazine groups provides highly dense cross-linked networks. The thermal cross-linking nature may be used to prepare high-performance thermoset polymers with diverse properties featuring self-supporting and flexible films. The hydrophilicity and wettability of Benzoxazine films can also be changed by light. Such material is well-suited for applications such as coating and microelectronics where film formation is needed.
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Coumarines as masked phenols for amide functional Benzoxazines
Polymer Chemistry, 2019Co-Authors: Gizem Kaya, Baris Kiskan, Yusuf YagciAbstract:Benzoxazines with amide linkages were successfully prepared. Initially, 3,4-dihydrocoumarine (DHC) was used as the reagent to synthesize phenolic amides via a ring-opening reaction using primary amines. The phenolic amides were then reacted with formaldehyde and primary amines to produce amide containing Benzoxazines. Moreover, the polymeric amide functional Benzoxazine precursor was prepared with bisamine end-functional poly(propylene oxide) by Mannich type polycondensation. The obtained polymer exhibited good film forming properties and free standing flexible films were easily solvent-cast on glass plates. All of the monomers and polymeric precursors were characterized by 1H NMR and FTIR spectroscopic analysis and their curing behavior and thermal stability were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Additionally, the mechanical properties of both cured and uncured polymeric Benzoxazine precursors were studied by tensile test measurements.
Baris Kiskan - One of the best experts on this subject based on the ideXlab platform.
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Side- and End-Chain Benzoxazine Functional Polymers
Handbook of Benzoxazine Resins, 2020Co-Authors: Baris Kiskan, Yusuf YagciAbstract:Publisher Summary This chapter describes synthetic pathways for the synthesis of side- and end-chain Benzoxazine functional polymers by using controlled and conventional polymerization methods involving free radical and rhodium catalysts. It presents numerous synthetic methods to combine Benzoxazines with polymers and contribute to increase the performance and property characteristics of these resins. These approaches may serve a valuable guideline for preparing polyBenzoxazines with desired properties to fulfill industrial demands. The synthesis of the polyBenzoxazine by cross-linking bifunctional Benzoxazine monomer through a ring-opening reaction is reported and the benefits of this family of compounds are identified. PolyBenzoxazines can offer various superior properties compared to the conventional novolac or resole or epoxy type resins. Though Benzoxazine based materials possess several advantages, they are not very attractive to the chemical industry because of problems of processability, brittleness, and high curing temperatures. Recently a new type of addition-cure phenolic system, polyBenzoxazine is developed. These materials offer low water absorption, high char yield, resistance against flame, high modulus, high strength, high glass transition temperatures, chemical resistance, and long shelf life; they have very limited volumetric change upon curing; and strong acid catalysts are not required for curing. Though polyBenzoxazines have such superior properties, pure Benzoxazine based thermosettings suffer from high curing temperatures (200 °C or higher), difficulty in processing, and brittleness. Another encouraging approach is the synthesis of novel polymeric Benzoxazine precursors, designed to impart flexibility and processability. Incorporation of Benzoxazine groups into a polymer backbone as a side chain is an important way to obtain a dense network. Various synthetic methods can be used to obtain such kinds of precursors.
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Benzoxazine resins as smart materials and future perspectives
Thermosets, 2020Co-Authors: Baris Kiskan, Yusuf YagciAbstract:Abstract PolyBenzoxazines are high-performance thermosets having a range of properties and capability to overcome drawbacks of traditional resole- and novolac-type phenolics. They exhibit low water absorption, high T g , high char yield, flame resistance, low shrinkage, and also limited or no release of by-products during curing, and they have comparable mechanical performance with bismaleimide resins. In this chapter, we provide an overview of polyBenzoxazines highlighting in the progress in the synthesis of both Benzoxazine monomers and polyBenzoxazine prepolymers, their resulting materials, and their composites. Moreover, industrially important Benzoxazines and current advances of Benzoxazine applications as smart materials ranging from self-healing materials to electroactive coatings were reviewed.
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Chapter 13 – Thiol-Benzoxazine Chemistry for Macromolecular Modifications
Advanced and Emerging Polybenzoxazine Science and Technology, 2020Co-Authors: Baris Kiskan, A. Musa, E. Semerci, Yusuf YagciAbstract:This chapter deals with the synthetic pathways of obtaining materials with thermally curable Benzoxazine moieties by using the catalytic opening of the lateral Benzoxazine rings by thiols (COLBERT), or in other words the thiol-Benzoxazine reaction to further improve special properties, particularly processibility and toughness or for designing new materials. The combination of COLBERT with photolytic thiol-ene, postpolymer modifications of main chain polyBenzoxazines, synthesis of linear, block copolymers, and hybrid networks are presented. The advantages of the thiol-Benzoxazine approach can be listed as fast and easy reaction conditions at ambient temperature or even below, 100% atom economy, and the availability of wide range of thiol compounds. Apart from these, the conventional benefits of Benzoxazine chemistry, like the ease of Benzoxazine synthesis and its design flexibility, can be considered additional virtues of thiol-Benzoxazine chemistry.
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Light-Induced Reactions of Benzoxazines and Derivatives
Handbook of Benzoxazine Resins, 2020Co-Authors: Mehmet Atilla Tasdelen, Baris Kiskan, Burcin Gacal, Fatmanur Kasapoglu, Luminita Cianga, Yusuf YagciAbstract:Publisher Summary This chapter describes photochemical routes for the incorporation of thermally polymerizable Benzoxazine in linear and cross-linked polymeric structures. It focuses on the use of both the free radical and cationic photoinitiating systems for Benzoxazine resins that provide some advantages or overcome existing problems and challenges in Benzoxazine chemistry. The photochemical degradation and UV stability of Benzoxazine resins are also discussed in this study. Benzoxazine resins are readily synthesized from Benzoxazine monomers, either monofunctional or of higher functionality. It elaborates that photoinitiated polymerization is an important industrial process widely used in different applications. This process induces the polymer formation with a fast transformation of the liquid monomer into a solid film with tailored physical chemical and mechanical properties. This is a striking advantage for both the classical polymerization of monofunctional monomers and modern curing applications. Photopolymerizations are simply polymerization reactions initiated by light, typically in the ultraviolet or visible region of the light spectrum. Photoinitiated polymerization can be divided into two categories: free radical and cationic polymerizations. Deep curing using the described photoinitiating system followed by the thermal ring-opening of the incorporated Benzoxazine groups provides highly dense cross-linked networks. The thermal cross-linking nature may be used to prepare high-performance thermoset polymers with diverse properties featuring self-supporting and flexible films. The hydrophilicity and wettability of Benzoxazine films can also be changed by light. Such material is well-suited for applications such as coating and microelectronics where film formation is needed.
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Coumarines as masked phenols for amide functional Benzoxazines
Polymer Chemistry, 2019Co-Authors: Gizem Kaya, Baris Kiskan, Yusuf YagciAbstract:Benzoxazines with amide linkages were successfully prepared. Initially, 3,4-dihydrocoumarine (DHC) was used as the reagent to synthesize phenolic amides via a ring-opening reaction using primary amines. The phenolic amides were then reacted with formaldehyde and primary amines to produce amide containing Benzoxazines. Moreover, the polymeric amide functional Benzoxazine precursor was prepared with bisamine end-functional poly(propylene oxide) by Mannich type polycondensation. The obtained polymer exhibited good film forming properties and free standing flexible films were easily solvent-cast on glass plates. All of the monomers and polymeric precursors were characterized by 1H NMR and FTIR spectroscopic analysis and their curing behavior and thermal stability were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Additionally, the mechanical properties of both cured and uncured polymeric Benzoxazine precursors were studied by tensile test measurements.
Tsutomu Takeichi - One of the best experts on this subject based on the ideXlab platform.
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effect of triphenyl phosphate flame retardant on properties of arylamine based polyBenzoxazines
Journal of Applied Polymer Science, 2013Co-Authors: Sarawut Rimdusit, Nuttiwan Thamprasom, Tsutomu Takeichi, Chanchira Jubsilp, Nitinat Suppakarn, Sunan TiptipakornAbstract:Three types of arylamine-based Benzoxazine resins modified with both condensed-phase and gas-phase action flame re- tardant, i.e. triphenyl phosphate (TPP) at various weight ratios were investigated. From rheological study, it was found that the vis- cosity of Benzoxazines/TPP mixtures were significantly lower than that of the neat Benzoxazine monomers suggesting flow property enhancement. Furthermore, differential scanning calorimetry results revealed that the onset and the maximum temperatures of the exothermic peak, due to the ring opening polymerization of Benzoxazine resins, shifted to lower temperatures with increasing TPP. In addition, all polyBenzoxazines possessed relatively high char yield, which increased as the TPP content increased thus enhancing their flame retardancy. The limiting oxygen index values of the flame retarded polyBenzoxazines also increased with TPP addition. The maximum flame retardancy of UL94 V-0 class was obtained with an addition of only few percents of TPP in the polyBenzoxazines. Flexural strength, flexural modulus, and glass transition temperature of those polyBenzoxazines tended to decrease with an addition of TPP mainly due to its plasticizing effect. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1074-1083, 2013
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Effect of triphenyl phosphate flame retardant on properties of arylamine‐based polyBenzoxazines
Journal of Applied Polymer Science, 2013Co-Authors: Sarawut Rimdusit, Nuttiwan Thamprasom, Tsutomu Takeichi, Chanchira Jubsilp, Nitinat Suppakarn, Sunan TiptipakornAbstract:Three types of arylamine-based Benzoxazine resins modified with both condensed-phase and gas-phase action flame re- tardant, i.e. triphenyl phosphate (TPP) at various weight ratios were investigated. From rheological study, it was found that the vis- cosity of Benzoxazines/TPP mixtures were significantly lower than that of the neat Benzoxazine monomers suggesting flow property enhancement. Furthermore, differential scanning calorimetry results revealed that the onset and the maximum temperatures of the exothermic peak, due to the ring opening polymerization of Benzoxazine resins, shifted to lower temperatures with increasing TPP. In addition, all polyBenzoxazines possessed relatively high char yield, which increased as the TPP content increased thus enhancing their flame retardancy. The limiting oxygen index values of the flame retarded polyBenzoxazines also increased with TPP addition. The maximum flame retardancy of UL94 V-0 class was obtained with an addition of only few percents of TPP in the polyBenzoxazines. Flexural strength, flexural modulus, and glass transition temperature of those polyBenzoxazines tended to decrease with an addition of TPP mainly due to its plasticizing effect. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1074-1083, 2013
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Synthesis and polymerization behavior of novel liquid-crystalline Benzoxazines
Polymer, 2011Co-Authors: Takehiro Kawauchi, Yuta Murai, Kazuhiro Hashimoto, Koichi Sakajiri, Tsutomu TakeichiAbstract:Abstract Novel liquid-crystalline (LC) Benzoxazines were synthesized by using 4(4′-heptoxybenzoyloxy)benzylidene-4″-aminophenol, various alkylamines, and formalin in chloroform under reflux. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) were used to analyze the LC behavior of the synthesized Benzoxazines. The novel Benzoxazines showed nematic and smectic phases upon cooling cycle from the isotropic liquids. The LC Benzoxazines also showed a nematic phase upon heating cycle, indicating that the novel Benzoxazines are enantiotropic liquid crystals. The ring-opening polymerization behavior of the LC Benzoxazines was investigated by DSC and IR analyses. POM observations showed that a polyBenzoxazine film, prepared by thermally curing the LC Benzoxazine up to 160 °C for 1 h, exhibited birefringence at room temperature.
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novel Benzoxazine monomers containing p phenyl propargyl ether polymerization of monomers and properties of polyBenzoxazines
Macromolecules, 2001Co-Authors: Tarek Agag, Tsutomu TakeichiAbstract:Novel Benzoxazine monomers containing arylpropargyl ether were prepared, and highly thermally stable polyBenzoxazines were obtained by the thermal cure of the monomers. One monomer is a monofunctional Benzoxazine, 4-propargyloxyphenyl- 3,4-dihydro-2H-1,3-Benzoxazine (P-appe), and the other is a bifunctional Benzoxazine, bis(4-propargyloxyphenyl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane (B-appe). The chemical structures of these novel monomers were confirmed by IR and 1H NMR. The cure behavior of the monomers, P-appe and B-appe, and the properties of the resulting polymers were studied in comparison with 4-phenyl-3,4-dihydro-2H-1,3-Benzoxazine (P-a) and bis(4-phenyl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane (B-a) as typical Benzoxazine monomers without propargyl groups. DSC cure of both P-appe and B-appe showed a single exotherm corresponding to the ring-opening polymerization of oxazine ring and cross-linking of arylpropargyl ether group at almost the same temperature range as P-a and B-a. The Tg values...
