Pterocarpus santalinus, listed in CITES Appendix II, is an endangered timber species as a result of illegal harvesting due to its high value and commercial demand. The growing demand for P. santalinus and timbers with the morphologically similar Pterocarpus tinctorius has resulted in confusion as well as identification problems. Therefore, it is of vital importance to explore reliable ways to accurately discriminate between P. santalinus and P. tinctorius. In this study, the method of direct analysis in real time and fourier transform ion cyclotron resonance mass spectrometry (DART-FTICR-MS), combined with multivariate statistical analysis, was used to extract chemical information from xylarium wood specimens and to explore the feasibility of distinguishing these two species. Significant differences were observed in their DART-FTICR-MS spectra. Orthogonal partial least square-discriminant analysis (OPLS-DA) showed the highest prediction, with an accuracy of 100%. These findings demonstrate the feasibility of authenticating wood types using DART-FTICR-MS coupled with multivariate statistical analysis.
To further clarify reasons for formation of condensed residues during the last stage of wood liquefaction in the medium of polyhydric alcohols and sulfuric acid catalyst, the weight loss behaviors and thermal reaction kinetics of condensed residues were studied by thermogravimetric analysis (TGA). Simultaneously, chemical methods were used to analyze the contents of lignin, cellulose, and holocellulose in the condensed residues. For all the unliquefied wood residues, the contents of cellulose decreased, and the residual ratios after TGA pyrolysis and the contents of lignin increased as a function of liquefaction time. Moreover, the highest weight loss rate went gradually to the higher temperature region after the liquefaction time and heating rate were extended. The values for apparent activation energy were lower at 150 minutes and 180 minutes and higher at 25 minutes. Liquefaction time had a smaller effect on the pyrolysis mechanism, as revealed by TGA. In conclusion, the thermal stabilities of condensed residues were higher than those of decomposed residues and wood. The condensation reaction occurred mainly during wood liquefaction, and condensed residues resulted possibly from mutual reaction among small molecules from decomposed lignin.
Polyhydric alcohols are known as excellent solvents for converting the main components of lignocellulose into liquefied products. However, the substances that precipitate in water include not only lignin, but also humins, especially when the lignocellulosic raw material has a high content of carbohydrates. Therefore, the main objective of this study was to investigate the composition of water-insoluble solids from the liquefaction of oil palm trunk using the solvent polyethylene glycol (PEG)/glycerol (4:1, w/w) and by using sulfuric acid as the catalyst. The results showed that the water-insoluble components had a relatively higher average molecular weight and polydispersity than those of the water-soluble components and liquefied products. The production of sugar monomers during liquefaction led to the condensation of furan products (hydroxymethylfurfural and furfural) to form humins. In this case, the humins were incorporated with the lignin and liquefying reagent.
Antimicrobial packaging is a hot research in food packaging research. A new type of antibacterial packaging film preparation was introduced in this paper. The new composite membrane was successfully prepared by using poly (succinic acid - adipic acid - butanediol) ester (PBSA) film as the base film through surface grafted approach, and nano-silver ions were used as antimicrobial agent in the antimicrobial film. The results showed that the new PBSA film has a good antibacterial antibacterial properties, and the best antibacterial agent formulations have been identified.
For exploring the variation of the surface morphology of carbon fiber precursor which was obtained from different curing conditions,this paper used the fractal dimension measurement method to analyze morphological characters of carbon fiber precursor surface through the electronic scanning electron microscopy image recognition and computer fractal calculation system. The experimental results show:the surface fractal dimensions of carbon fiber precursor were between 2.480~2.622 by TPSAM method, and the surface fractal dimensions of carbon fiber precursor were between 2.555~2.633 by PCM method, both methods show that the carbon fiber precursor surface is smooth. And the CCM is 2.678~2.755, this method shows that the precursor surface is concave and convex. The fractal dimension value obtained by TPSAM method and PCM method is closer, while the CCM is different. But the trend is almost the same, which shows that using the fractal dimension method to desirable the surface structure of carbon fiber precursor is desirable.
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