Publications by authors named "Korawit Chitbanyong"

TEMPO-catalyzed oxidation is a unique method for converting primary C6-hydroxymethyl groups in water-insoluble regenerated cellulose materials to sodium C6-carboxylate groups in water at room temperature to provide water-soluble polyglucuronates. In this study, 20 % NaOH-treated bacterial cellulose (BC), cotton lint (CL), and ramie cellulose (RC) were oxidized to prepare water-soluble polyglucuronates with high degrees of polymerization and high mass recovery ratios. Solid-state CP/MASS C NMR spectra of the water-soluble products indicated that they contained considerable amounts of C2/C3-ketone hydrate structures (50-60 % of glucuronosyl units).

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Phosphorylated (P-) and TEMPO-oxidized (TO-) wood cellulose fibers (pulps), and P- and TO-cellulose nanofibrils (CNFs) were prepared. To extract pure cellulose molecules, all samples were dispersed in water and freeze-dried, and the P-/TO-pulp and P-/TO-CNF samples were stirred in 8 % (w/w) lithium chloride/N,N-dimethylacetamide (LiCl/DMAc). The quantities of the extracted LiCl/DMAc-soluble fractions and molar-masses of the constituents were determined using size-exclusion chromatography.

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Three commercial regenerated cellulose samples were subjected to TEMPO-catalyzed oxidation using solid NaOCl·5HO as the primary oxidant for structural analyses of the oxidized products (TEMPO = 2,2,6,6-tetramethylpiperidine-1-oxyl). The regenerated cellulose/water slurries became transparent solutions after oxidation for 60 min. The yields of the oxidized products were almost 100 % when they were isolated as precipitates in ethanol/water mixtures.

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Side reactions occurring on cellulose during 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TMEPO)-catalyzed oxidation have not been considered to be significant. Then, TEMPO-oxidized hardwood and softwood bleached kraft pulps (HBKP and SBKP) were prepared with an excess NaOCl·5HO. Supernatant fractions (SFs) were obtained in the aqueous reaction mixtures of TEMPO-oxidized pulps by centrifugation and dialysis.

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2,2,6,6-Tetramethylpiperidine-1-oxyl radical (TEMPO)-catalytic oxidation was applied to a water-insoluble α-(1 → 3)-glucan in water at pH 10 and room temperature (∼24 °C), with solid NaOCl·5HO as the primary oxidant. Oxidation with NaOCl at 15 mmol/g gave a water-soluble TEMPO-oxidized product at a mass recovery ratio of 97 %. The carboxy content of the TEMPO-oxidized product was 5.

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The objective of this study was to investigate the morphological and chemical properties of hemp bast RPF1 variety fiber to be used as a potential raw material for filter paper production. Experimental handsheet samples with basis weight of 20 g/m were manufactured using mixture of hemp and softwood pulp at various beating levels. The average fiber length and width of hemp bast fiber were determined as 5.

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In this paper, we present the morphology, taxonomy, anatomy, and palynology of . A detailed morphological description and illustrations of the species are provided, along with information about the identification, distribution, the specimens examined, habitat and ecology, the International Union for Conservation of Nature (IUCN) conservation assessment, phenology, etymology, vernacular name, and uses. The species can be distinguished by its large, tall rhizomatous perennial reed; cauline leaves; an open, large, plumose panicle inflorescence; subequal glumes as long as the spikelets; glabrous rachilla; all bisexual florets; and a lemma with a straight awn and with long white hairs outside below the middle part.

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Bacterial cellulose (BC), prepared from two recently developed thermotolerant bacterial strains (Komagataeibacter xylinus C30 and Komagataeibacter oboediens R37-9), were used as a raw material to synthesize nanofibril films. Field-emission scanning electron microscope (FE-SEM) observations confirmed the ultrafine nano-structure of BC pellicle (BCP) with average fibril widths between 50 and 60 nm. The BC was directly oxidized in a TEMPO/NaBr/NaClO system at pH of 10 for 2 h.

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The aim of this study was to create a reinforced composite wood-based panel that would be leaned towards the environment Plywood was used as a core material and fiber-reinforced polymer was used as a reinforcement. Conventional resin for the fiber-reinforced polymer was substituted with polyvinyl acetate (PVAC), which has several advantages, such as a lower price, easier handling, and better degradability. The second chosen component, basalt fiber, is cost attractive and environmentally friendly.

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