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Abstract: Activated carbons were investigated for their heat catalytic effects to improve saccharification of starch by autohydrolysis in water under microwave electromagnetic field, and the results were compared with graphite and carbon nanotubes. The activated carbons with low adsorptive capacity of maltose showed high saccharification rate, while those with high adsorptive capacity exhibited low saccharification. In addition, the former activated carbons decreased the saccharification temperature by 10–30°C. Maltooligosaccharides produced in the presence of the latter activated carbons were recovered by desorption with 50% aqueous ethanol. The results indicated that both adsorptive capacities of maltooligosaccharides and catalytic effects of hot spots arisen from the uneven surface structure of activated carbons might contribute to the improvement in starch saccharification. [ABSTRACT FROM AUTHOR]

• Synthesis of polymerizable TLAs as the styrene and methacrylate derivatives. • Therman deprotection and decomposition behavior of the TLA homopolymers. • Copolymerization of PBHEMA with the TLAs and the characterization of the resulting copolymers. • Achievement of thermal stability during storage and quick deprotection on heating using the methacrylate -type TLAs. Poly((2‑ tert -butoxycarbonyloxy)ethyl methacrylate) (PBHEMA) is converted to poly(2-hydroxyethyl methacrylate) (PHEMA) with the release of isobutene and CO 2 by heating and this reaction is accelerated by an acid. The thermally latent acid catalysts (TLA) are useful for the control of a working temperature for the deprotection of the tert ‑butoxycarbonyl (BOC) groups included in PBHEMA. In this study, styrene- and methacrylate-type sulfonic esters were synthesized and copolymerized with BHEMA in order to investigate the effect of the TLAs incorporated into the polymer chains. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were carried out for the copolymers of BHEMA with the polymerizable TLAs in order to discuss the deprotection features of the BOC group in comparison with the results for the systems of PBHEMA blended with the low-molecular-weight TLAs. [Display omitted] [ABSTRACT FROM AUTHOR]

In organic synthesis and polymer materials chemistry, a tert -butoxycarbonyl (BOC) group is often used as one of tools for the protection of functional groups. In this study, we carried out radical polymerization of 2-(tert -butoxycarbonyloxy)ethyl methacrylate (BHEMA) and copolymerizations of BHEMA with methyl methacrylate (MMA), n -butyl methacrylate (nBMA), isobutyl methacrylate (iBMA), tert -butyl methacrylate (tBMA), dodecyl methacrylate (DMA), α-methylstyrene (AMS), and limonene (Lim) as the 1,1-disubstituted ethylene monomers and investigated the thermal decomposition behavior of the obtained polymers. On the basis of the results of thermogravimetric (TG) analysis in nitrogen at the heating rate of 10 °C/min, it was revealed that the deprotection of the BOC group in the polymer side chains occurred at ca. 200 °C accompanying the quantitative elimination of isobutene and carbon dioxide, independent of the structures of the repeating units. The following main-chain decomposition of the residual copolymers resulted in a small amount of residue less than 1% at 500 °C. Poly(2-hydroxyethyl methacrylate) was synthesized via the deprotection of the BOC group of PBHEMA. • A new BOC-containing monomer BHEMA was conveniently synthesized from HEMA. • The polymers containing BHEMA units were prepared by radical polymerization and copolymerization. • The thermally decomposition behavior of the BHEMA-containing polymers was investigated. • The BHEMA-containing polymers were thermally stable below 100 °C and rapidly decomposed at 200 °C accompanying quantitative elimination of isobutene and carbon dioxide. • PBHEMA was readily converted to PHEMA by thermolysis. [ABSTRACT FROM AUTHOR]

Abstract The alternating copolymer of a conjugated diene monomer and oxygen, i.e., polyperoxide, is a main-chain degradable polymer and undergoes radical chain degradation by heating. During the degradation process, oxygen-centered radicals are formed and thus side reactions such as hydrogen abstraction from the polymer by the oxygen-centered radicals and subsequent coupling, which prevent the degradation, sometimes take place. In this study, in order to promote the degradation of polyperoxides only at elevated temperatures while maintaining their stability at ambient temperature, appropriate organic reductants, which do not significantly react with the polyperoxides at 30 °C but react at 100 °C, were explored. N , N -Dimethylaniline, which is a conventional reductant for redox initiation systems, initiated the redox degradation of cyclopentadiene-based polyperoxides even at 30 °C due to the very high nucleophilicity. The introduction of an electron donating group at the para position, i.e., 4-dimethylaminoacetophenone, 4-dimethylaminobenzaldehyde, and 4-dimethylaminobenzonitrile, successfully maintained the stability of the polyperoxide at 30 °C and accelerated the degradation at 100 °C due to the reduced nucleophilicity. Similar results were obtained by using 1-acetyl-2-phenylhydrazine and 1-phenyl-3-pyrazolidone (PhP) as a reductant, and PhP resulted in the most significant acceleration effect at 100 °C. The activation energy for the overall degradation of the polyperoxide in the presence of PhP was much lower than that of the polyperoxide in the absence of a reductant. In the case of sorbic ester-based polyperoxides, their stabilities at 30 °C were not maintained in the presence of the reductants and the stability was improved by increasing the 2,5 structure regarding the diene moiety in the main-chain. Highlights • Accelerated degradation of polyperoxides only at elevated temperatures was achieved by the selection of reductants. • The activation energies for the degradation of the polyperoxides in the presence of the reductants were determined. • Effects of the main chain structures of the polyperoxides containing the reductants on their stability were determined. [ABSTRACT FROM AUTHOR]

The acrylate copolymers consisting of 4-hydroxybutyl acrylate (HBA), 2-(tert -butoxy-carbonyloxy)ethyl acrylate (BHEA) or 4-(tert -butoxycarbonyloxy)butyl acrylate (BHBA), and 2-ethylhexyl acrylate (2EHA) as the repeating units were synthesized by radical copolymerization. The performance as the pressure-sensitive adhesives (PSAs) used for a dismantlable adhesion system was investigated. The glass transition temperatures and the adhesive properties were precisely controlled by the comonomer composition of the copolymers. It was confirmed that the deprotection of the tert -butoxycarbonyl (BOC) group rapidly proceeded for the BOC-containing acrylate copolymers as the PSAs. It resulted in the decrease of the adhesion strength during a debonding process by heating. The thermal stability during use and the quick response for on-demand debonding were simultaneously achieved by the use of alkyl p -toluenesulfonates as the thermally latent acids (TLAs). [Display omitted] • Acrylate copolymers including the BOC groups for PSAs were synthesized. • T g and adhesive properties were precisely controlled using HBA and BHBA monomers. • Adhesion strength of the BOC-containing PSAs was investigated before and after heating for on-demand debonding. • Thermal stability during use and quick response for debonding were simultaneously achieved by the use of the thermally latent acids. [ABSTRACT FROM AUTHOR]

A drastic change in the bulk properties of adhesive materials as well as a reduction of interfacial interaction is an important key for the development of dismantlable adhesion systems, i.e., reliable bonding systems with a function of on-demand debonding. The deprotection of tert -butoxycarbonyloxy (BOC) groups included in adhesive polymers can be applied to the construction of a dismantlable adhesion system for steel plates combined with acrylic and epoxy adhesives. In this study, we evaluated the adhesive properties of the copolymers of 2-(tert -butoxycarbonyloxy)ethyl methacrylate (BHEMA), glycidyl methacrylate (GMA), and 3-trimethoxysilylpropyl methacrylate (SMA) for the dismantlable bonding of steel plate cold commercial (SPCC). Spontaneous dismantling of the SPCC adhesive structures was achieved after heat treatment under the conditions at 210 °C for 15 min when the BHEMA/GMA/SMA copolymers with an appropriate copolymer composition were used as the acrylic adhesives or the primers for epoxy adhesion. We discuss the interfacial interactions between the adherend and the adhesives for reliable adhesion and the effects of the deprotection of the BOC groups for dismantling to exhibit both an adhesion strength required for metal bonding and a rapid decrease in the strength by thermal stimulus. • A new thermally-responsive dismantlable adhesion system of steel plates (SPCC) using BOC containing polymers is proposed. • The methacrylate copolymers including 2-(tert -butoxycarbonyloxy)ethyl, glycidyl, and 3-trimethoxysilylpropyl esters were prepared by radical copolymerization in order to investigate their thermal properties. • BOC containing copolymers were used as the acrylic adhesive or the primer of the epoxy adhesive for SPCC bonding. • Spontaneous dismantling of the SPCC adhesive structures was achieved after heating at 210 °C for 15 min. [ABSTRACT FROM AUTHOR]

Co-continuous network polymers (CNPs) as the new polymer composites are fabricated by filling the continuous pores of an epoxy monolith with a high glass transition temperature (T g) using another kind of network polymer with a low T g. In this study, we prepared sheet-like and cylindrical CNPs using thiol–ene thermosets as the second component with a low T g. A thiol–ene reaction is suitable for the preparation of thermosets with a controlled network structure. Here, various thiols and acrylates including the different numbers of functional groups and/or oligo(ethylene oxide) spacers with different lengths are used for the fabrication of the second thermosetting component. We investigated the tensile and compression mechanical properties of the produced CNPs. Dynamic mechanical analysis (DMA) of the thiol–ene bulk thermosets (BTs) as the second component was also carried out in order to clarify the influence of the T g and the crosslinking density on the mechanical and physical properties of the CNPs. The results of the mechanical tests were discussed on the functionality of the used acrylate and thiol compounds. In conclusion, we have revealed that the properties of CNPs are not only dependent on the crosslinking density, but also significantly affected by the detailed network structure of the second component. [Display omitted] • Preparation of sheet- and cylinder-type CNPs using thiol–ene thermosetting resins as the second component • Higher strength for the CNPs than that of the original monolith • Effects of the network structures of second components on the properties of the CNPs • Macroscopic deformation behavior and fracture mechanism of the CNPs [ABSTRACT FROM AUTHOR]

Radical copolymerization of lithium p -styrenesulfonate (LiSS) was investigated in aqueous media under various comonomer, initiator, and solvent conditions. The copolymerization of LiSS with acrylamide (AAm) provided random copolymers with LiSS-rich composition at an earlier stage of the reaction, then the homopolymerization of AAm started with spontaneous delay after the almost consumption of LiSS at a conversion over 95%. Such unique polymerization behavior was observed for the copolymerization of highly reactive sulfonate monomers such as LiSS and sodium p -styrenesulfonate (NaSS) combined with less-reactive comonomers such as AAm, N -vinylacetamide, and potassium 3-(acryloyloxy)propanesulfonate. The reaction mechanism and kinetic features for the two-step polymerization consisting of random copolymerization followed by the spontaneously delayed homopolymerization are described in detail. [Display omitted] • Radical copolymerization of lithium and sodium p -styrenesulfonates with various vinyl monomers in aqueous media. • Two-step polymerization process of the random copolymerization of the highly reactive styrenesulfonate monomers followed by the homopolymerization of a less-reactive monomer with spontaneous delay. • The effects of the reaction conditions such as the monomers, initiators, and solvents on copolymerization kinetics and mechanism. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

New kind of polymer composites, i.e., co-continuous network polymers (CNP), were fabricated by the filling of the continuous pores of an epoxy monolith (EM) with a cross-linked acrylate polymer. The internal structures of EM and CNP were non-destructively observed by X-ray CT imaging. The mechanical properties of EM were highly dependent on the pore and epoxy frame sizes. Increasing the molar ratio of the amino groups to glycidyl groups during the monolith fabrication process created a coarser co-continuous structure. It greatly enhanced the stretching property of EM. Filling the pores of EM with a rubbery cross-linked acrylate polymer as the second component increased the maximum strength of CNP, independent of the pore size. Furthermore, the gap formation at the boundary between the hard phase and the soft phase of CNP was observed by X-ray CT imaging for the broken test piece used for a tensile test. We discussed a mechanism for the deformation and fracture of EM and CNP. [Display omitted] • Fabrication of epoxy monolith as the porous materials and CNP as the polymer composite. • Non-destructive observation of internal structures by X-ray CT imaging. • Increase in strength by filling the pore of epoxy monolith with polyacrylate networks. • Unique mechanical property and fracture mechanism of epoxy monolith and CNP. [ABSTRACT FROM AUTHOR]

• Thermal deprotection behavior of IPTS and CHTS as the TLAs was clarified. • The kinetic parameters of the deprotection of the TLAs were determined by isothermal TG analysis. • An acceleration mechanism and kinetics for the deprotection of PBHEMA in the presence of the TLAs were investigated. • Thermal stability during storage and quick deprotection on heating were simultaneously achieved for PBHEMA by using the TLAs. Poly(2-(tert ‑butoxycarbonyloxy)ethyl methacrylate) (PBHEMA) is converted to poly(2-hydroxyethyl methacrylate) with the release of isobutene and carbon dioxide gasses when it is heated at a high temperature over 200 °C. The deprotection of PBHEMA is accelerated by the addition of an acid, but it is simultaneously disadvantageous for the storage and handling of the polymer at an ambient temperature. In this study, we propose the use of thermal acid generators, i.e., thermally latent acids (TLAs) as the catalysts to control a reaction rate and a working temperature for the deprotection of PBHEMA. We investigated the thermal deprotection behavior of some sulfonates including isopropyl p -toluenesulfonate (IPTS) and cyclohexyl p -toluenesulfonate (CHTS). The kinetic parameters for the deprotection, which provides p -toluenesulfonic acid (TsOH) as the reaction product, were determined by thermogravimetric (TG) analysis under the isothermal condition. A remarkable auto-catalytic effect actually resulted in a rapid deprotection to produce TsOH in a narrow temperature range under the non-isothermal conditions. The additive effect of the TLAs on the deprotection of the BOC groups contained in the side chain of PBHEMA was similarly investigated. It was revealed that the deprotection of PBHEMA rapidly proceeded by the addition of IPTS and CHTS under the heating conditions over 100 °C. PBHEMA was stable at a temperature below the onset temperature of the deprotection of the TLAs. The deprotection kinetics of PBHEMA and a detailed mechanism for the control of the reactions in the presence of the TLAs were clarified. [Display omitted] [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Dynamical behavior and glass transitions in copolymers of diisopropyl fumarate (DiPF) with 1-adamantyl acrylate (AdA) or n-butyl acrylate (nBA) are investigated by dielectric relaxation spectroscopy (DRS) to elucidate the effect of structural constraint due to the absence of a CH 2 spacer on the dynamics. DRS measurements revealed that the two copolymers exhibit three dynamical processes: α -, β -, and γ -processes. The relaxation time of the β -process can be described by the Vogel-Fulcher-Tammann (VFT) law in addition to the α -process. Hence, two glass transition temperatures, T g , can be evaluated from α - and β -processes. The AdA and nBA fraction dependence of T g s is consistent with that obtained by dynamical mechanical analysis. The Vogel temperature of the α -process is nearly equal to that of the β -process for the PDiPF homopolymer. With the increase in the AdA fraction, the difference in the Vogel temperature between the α - and β -processes increases. This result suggested that there is an intrinsic correlation between the α - and β -processes for PDiPF, and the correlation changes with the AdA fraction. From the nBA fraction dependence of the β -process, the β -process of PDiPF can be related to the segmental motion of the main chain. Nevertheless, PDiPF exhibits a solid-like property up to the T g , which is related to the α -process. The physical origins of other processes also were discussed. [Display omitted] • Dielectric measurements have been performed for polyfumarate copolymers. • Glassy dynamics of polyfumarate copolymers have been elucidated. • Origin of the three relaxation processes has been discussed. [ABSTRACT FROM AUTHOR]

• Random and block poly(MPC-co-dodecyl methacrylate)s (rPMDs and bPMDs) were synthesized. • Short rPMDs with different compositions were stably coated at the substrate but bPMDs were not. • Short rPMDs with different compositions showed efficient antifouling effects. • Short rPMDs with 34 and 92 mol% in MPC did not form hydrophobic domains. Copolymers comprising 2-methacryloyloxyethyl phosphorylcholine (MPC) are useful in the production of biomedical devices because of the antifouling effects. As copolymers of MPC with a hydrophobic comonomer are used as a coating agent, their composition, molecular weight, and sequence possibly impact their antifouling effect. In this study, random and block PMDs (rPMDs and bPMDs, respectively) with different compositions were synthesized, and their antifouling effects were examined. Short rPMDs (approximately 50 kDa) with different MPC compositions, from 34 mol% to 85 mol%, were stably coated and suppressed the adhesion of HeLa cells efficiently. rPMDs with 66 mol% and 85 mol% in MPC showed hydrophobic domains at the surface, to which macrophage-like RAW264 cells were adhered. However, rPMDs with 34 mol% and 92 mol% in MPC showed neither hydrophobic domains nor the adhesion of RAW264 cells after the 1-day culture. On the other hand, the antifouling effects of bPMDs were lower than those of rPMDs because of the micelle formation. Therefore, our results suggest that a variety of rPMDs with different MPC contents and different molecular weights can be used as coating agents, which are different from the poly(MPC- co -butyl methacrylate)s used conventionally. [ABSTRACT FROM AUTHOR]

Poly(diisopropyl fumarate) (PDiPF) has dynamic mechanical properties different from the relaxation processes of conventional vinyl polymers, due to the absence of a methylene spacer in the main chain. In this study, we investigated the relaxation behavior of PDiPF using dielectric spectroscopy (DS), differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS), and dynamic mechanical analysis (DMA). We have demonstrated that the β relaxation of PDiPF has unusual characteristics originating from the absence of a methylene spacer; for example, the β relaxation of PDiPF follows the Vogel–Fulcher–Tammann (VFT) equation, causes a clear step in the DSC curve, and enhances the microscopic packing of the polymer chains in the solid state. These β relaxation behaviors of PDiPF reflect the enlarged cooperative rearranging region (CRR). Image 1 • Mechanical and dielectric properties of poly(diisopropyl fumarate). • Effect of no methylene spacer on polymer dynamics. • β relaxation of poly(diisopropyl fumarate). [ABSTRACT FROM AUTHOR]