Tsuda S.,Yokohama National University |
Oyama T.,Yokohama National University |
Takahashi A.,Yokohama National University |
Okabe Y.,Hitachi Ltd. |
And 3 more authors.
An epoxidized lignophenol (ELP) was synthesized by a two-step reaction from a lignophenol (LP) as the starting material. The reaction of LP with epichlorohydrin was carried out in the presence of a phase transfer catalyst, tetrabutylammonium bromide, at 90°C without alkaline reagent, followed by epoxidation with aq. NaOH solution. Epoxy groups in ELP were found to react with phenolic OH groups of coniferyl alcohol as a model compound of LP, which was used as a curing agent in this study. Direct curing of ELP with LP resulted in heterogeneous cured resins, and therefore, petrochemical epoxy resins of bisphenol A diglycidyl ether (DGEBA) and 3,4-epoxycyclohexylmethyl 3′ ,4′-epoxycyclohexanecarboxylate (ECEC) were used with ELP in order to improve the fluidity of the systems. Epoxy resins that mixed ELP with DGEBA or ECEC were cured with LP by heating up to 180°C in the presence of imidazole derivative (2E4MZ-CN) ; these afforded ELBL and ELCL as novel thermosetting resins. The ELBL and ELCL showed well-balanced thermal and mechanical properties. Especially, the glass transition temperature (Tg) of the ELCL (70) , which included 30 wt% of ECEC as the epoxy resin where the total amount of LP element was 82 wt%, was 219°C. This value was 85°C higher than that of the conventional phenol novolac-cured DGEBA. These results demonstrated that LP was a promising biomass material for thermosetting resins. © 2010, The Society of Polymer Science,. Source
Shirafuji T.,Osaka City University |
Noguchi Y.,Nagoya University |
Yamamoto T.,Nagoya University |
Hieda J.,Tohoku University |
And 5 more authors.
Japanese Journal of Applied Physics
Solution plasma processing (SPP) has been performed on multiwalled carbon nanotubes (MWCNTs) in ammonia aqueous solution. The MWCNTs, which do not disperse in aqueous solution, uniformly dispersed after the SPP. Only 2 h was required to obtain 10 g of the dispersed MWCNTs, while 7 days and additional chemicals were required for 185mg in a previous study. The X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy of the SPP-treated MWCNTs revealed that nitrogen- and oxygen-containing groups are formed on the MWCNTs. Serious damage to the MWCNT structure was not observed in the Raman spectrum or transmission electron microscopy images of the SPP-treated MWCNTs. The composite materials prepared using polyamide 6 with the SPP-treated MWCNTs showed better tensile, bending, and impact strength than those prepared with nontreated MWCNTs. © 2013 The Japan Society of Applied Physics. Source