Guaiacol novolak (GCN) and wood-tar creosote novolak (WCN) were synthesized by the reactions of wood-derived guaiacol and creosote with formalin, respectively, and used as hardeners of sorbitol polyglycidyl ether (SPE). Thermal and mechanical properties of the cured resins (SPE-GCN and SPE-WCN) and their biocomposites with wood flour (WF) were compared with those of the materials prepared by using a petroleum-based phenol novolak (PN). Although tan d peak temperatures of SPE-GCN and SPE-WCN were lower than that of SPE-PN, that (58.5-70.8 C) of SPE-GCN/WF(40-50 wt %) was higher than that (56.6-57.0 C) of SPE-PN/WF(40-50 wt %). Tensile moduli of all the biocomposites increased by the addition of WF, while tensile strengths were rather reduced. When the biocomposites with the same WF content were compared, tensile modulus of SPE-GCN/WF was higher than that of SPE-PN/WF. The 5% weight loss temperatures (346-291 C) of SPE-GCN and SPE-GCN/WF were comparable to those (338-284 C) of SPE-PN and SPE-PN/WF.

Due to the biological importance of α-amino acids and their derivatives, the development of novel colorimetric probes for these molecules has been an active research area in recent years. In this study, surface-enhanced photochromic phenomena by various α-amino acids (L-aspartic acid [Asp], L-leucine [Leu], and L-lysine [Lys]) adsorbed on molybdenum(VI) oxide (MoO 3) nanoparticles in an aqueous system were investigated by means of UV-vis absorption spectrometry. No derivatization of α-amino acids is required, and eventually highly accurate determinations are obtained from the UV-induced MoO 3 photochromic coloration. Under optimal conditions in this system, limit of quantitation (LOQ) values of 3.45 10-6 , 2.08 10-6 , and 1.53 10-6 mol dm-3 for Asp, Leu, and Lys, respectively, were achieved at pH 2. During UV irradiation, the detection process could be visually observed by naked eyes. A simple and unique approach to explore sensitive "label-free" colorimetric sensing toward α-amino acids is proposed.

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