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Soybean meal-based adhesives (SMAs) commercially applied in wood-based composites require stable bonding properties. However, the structure and properties of SMAs are not as stable as synthetic resins, which significantly affect their performances. In this study, the structure–property evolution of a SMA with working time was systematically investigated. The findings revealed that the secondary structure, microstructure, crosslinking density, zeta potential, nitrogen solubility index, viscosity, wood permeability, and bonding properties of SMA considerably vary with working time. The changes in adhesive properties were correlated with the dissolution of SM particles in crosslinker solution and the increased pre-curing of liquid SMA with working time resulting from the crosslinking reactions between the dissolved SM and the crosslinker. Preferably, SMA at the working time between 0.5 h and 3 h since the mixing of soybean meal flour with crosslinker solution, should be used in order to ensure the desired water resistance of plywood panels for engineered wood flooring. And an application strategy was proposed to ensure the required water resistance of plywood panels for manufacturing engineered wood flooring. [ABSTRACT FROM AUTHOR]

Yb-Er and Yb-Tm activated novel garnet structure CaLaZrGaO phosphors were synthesized by solid state reaction and its upconversion luminescence properties were investigated. X-ray diffraction patterns confirmed the synthesized samples were indexed to the garnet structure. The upconversion emission spectra revealed that under 980 nm laser excitation, bright green and blue light had been achieved in CaLaZrGaO:Yb,Er and CaLaZrGaO:Yb,Tm phosphors, respectively. Yb acted as sensitizers in the upconversion process and did not show its characteristic emission peak. Strong Er and Tm emission peaks were obtained via energy transfer from Yb. The possible energy transfer processes of Yb to Er and Tm were discussed. The results indicated that Yb-Er and Yb-Tm activated CaLaZrGaO phosphors exhibited excellent upconversion luminescence properties. [ABSTRACT FROM AUTHOR]

Theeffect of surfactant micelles on the photophysical propertiesof a cationic bispyrene fluorophore, Py-diIM-Py, was systemicallyexamined. The results from series of measurements including UV–visabsorption, steady-state fluorescence emission, quantum yield, fluorescencelifetime, and time-resolved emission spectra reveal that the cationicfluorophore is only encapsulated by the anionic sodium dodecyl sulfate(SDS) surfactant micelles and not incorporated in the cationic dodecyltrimethylammoniumbromide (DTAB) and neutral Triton X-100 (TX100) surfactant micelles.This different fluorophore location in the micellar solutions significantlyinfluences its sensing behavior to various explosives. Fluorescencequenching studies reveal that the simple variation of micellar systemsleads to significant changes in the sensitivity and selectivity ofthe fluorescent sensor to explosives. The sensor exhibits an on–offresponse to multiple explosives with the highest sensitivity to picricacid (PA) in the anionic SDS micelles. In the cationic DTAB micelles,it displays the highest on–off responses to PYX. Both the sensitivityand selectivity to PYX in the cationic micelles are enhanced comparedwith that to PA in the anionic micelles. However, the poor encapsulationin the neutral surfactant TX100 micelles leads to fluorescence instabilityof the fluorophore and fails to function as a sensor system. Time-resolvedfluorescence decays in the presence of explosives reveal that thequenching mechanism of two micellar sensor systems to explosives isstatic in nature. The present work demonstrates that the electrostaticinteraction between the cationic fluorophore and differently chargedmicelles plays a determinative role in adjusting its distributionin micellar solutions, which further influences the sensing behaviorof the obtained micellar sensor systems. [ABSTRACT FROM AUTHOR]