We prepared maleimide copolymers with a well-defined sequence structure by the sequence-controlled radical copolymerization of N-substituted maleimides with an olefin monomer and realed the excellent thermal stability and high transparency of the copolymers. The copolymers consisting of N-allylmaleimide (AMI) and N-(2-ethylhexyl)maleimide (2EHMI) as the maleimide repeating units and diisobutylene (DIB) as the olefin unit (PAED-X) were thermally or photochemically cured using pentaerythritol tetrakis(3-mercaptobutyrate) (PEMB) as a polyfunctional thiol by a thiol-ene reaction. The effects of a reaction temperature, time, and atmosphere on the curing behavior were investigated. The organicinorganic hybrid was also fabricated by the thiol-ene reaction of the PAED-X with silica nanoparticles (SNP) containing a reactive mercapto group at the particle surface. The thermal and optical properties of the obtained PAED-X/SNP hybrids were revealed. We demonstrated the fabrication of the organic－inorganic hybrids exhibiting excellent thermal stability and high transparency by the combination of the maleimide copolymers with silica nanoparticles.

View full abstract

Water-dispersible copolymers containing isothiocyanate moiety, poly(ITEMA-co-AAm) were synthesized by radical copolymerization of 2-isothiocyanatoethyl methacrylate (ITEMA) and acryl amide (AAm). After checking of water solubility of copolymers carrying various compositions, only [ITEMA (7 mol%)-co-AAm (93 mol%)] is dispersible in water. Isothiocyanate groups in the copolymer were stable in water for one week at room temperature. To cross-link the copolymers in water, 1,6-hexamethylenediamine was added into their aqueous dispersion to obtain the corresponding networked polymers. After that, cross-linked copolymer was obtained with keeping its water-dispersibility. Further, hydrogel was obtained by heating the copolymer dispersion at 100 ℃ for 30 min to be insoluble in any solvents. At higher temperature (at 100 ℃), isothiocyanate groups reacted with water to give amino groups and subsequently obtained amino groups reacted with isothiocyanate groups to form networked hydrogel. Based on these results, poly(ITEMA-co-AAm) may be useful as key precursor for forming networked polymers in water.

View full abstract

The interactions between positively-charged-liposomes (liposomes) and pyrene-labeled hydrophobically-modified sodium poly-2-(acrylamido)-2-methylpropane sulfonates (PAMPSs) have been examined by fluorescence spectroscopy and dynamic light scattering. Evidence from changes in the relative intensity of pyrene excimer and monomer emissions indicates that the PAMPS carrying 5 mol% pyrenylbutyl-n-octadecyl group binds to the liposomes and that, for systems in 0.2 M aqueous NaCl, the binding is only mildly affected by the charge density of the liposomes. The reversibility of binding of the PAMPSs to the liposomes was assessed by addition of the polycations, (N-isopropylacrylamide)-N-dimethylethyl(2- acrylamido-ethyl)ammonium bromide copolymers. Based on the level of pyrene fluorescence recovery upon addition of the polycations to the complexes between the PAMPSs and liposome carrying a quencher of pyrene fluorescence in its bilayer, we demonstrate that a pyrene-labeled PAMPS without hydrophobic groups desorbs from the surface of the liposoems. In contrast, under the same condition, a pyrene-labeled PAMPS carrying 5 mol% n-octadecyl group is not desorbed from the surface of the liposomes.

View full abstract

Effects of curing temperature on the properties and wear resistance of fluoropolymer coating films using commercially available low-temperature cured type materials were investigated. Treatment of higher curing temperature improved pencil hardness, non-stick property, and abrasion resistance against wool felts. Surfaces of films were analyzed by ATR－FTIR spectroscopy and ESCA spectroscopy. The results of the films containing PTFE and FEP indicated that content of fluoropolymer was decreased after wiping by wool felts.

View full abstract

Epoxy resin is widely used in Carbon Fiber Reinforced Plastics (CFRP) for its good mechanical properties; heat resistance and adhesion with CF. Recent advancements of molding technologies require epoxy resins tailored to fit various molding processes. In this article, molding methods for CFRP and key elements regarding the design of epoxy resin for these techniques are overviewed including latest related technologies.

View full abstract

[in Japanese]

View full abstract