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The dry-pulp direct-kneading method is an industrially viable, low-energy process to manufacture cellulose nanofiber (CNF) reinforced polymer composites, where chemically modified pulps can be nanofibrillated and dispersed uniformly in the polymer matrix during melt-compounding. In this study, cellulose fibers with different sizes, ranging from surface-fibrillated pulps with 20 µm in width to fine CNFs with 20 nm in width were prepared from softwood bleached kraft pulps (NBKPs) using a refiner and high-pressure homogenizer (HPH). These cellulose fibers were modified with alkenyl succinic anhydride (ASA), and then dried. The dried ASA-treated cellulose fibers were used as a feed material for melt-compounding in the dry-pulp direct kneading method to fabricate CNF reinforced high-density polyethylene (HDPE). When surface-fibrillated pulps were employed as a feed material, the pulps were nanofibrillated and dispersed uniformly in the HDPE matrix during the melt-compounding, and the composites had much better properties (i.e., much higher tensile modulus and strength and much lower coefficient of thermal expansion) than the composites produced using the pulps without pre-fibrillation. However, when CNFs were used as a feed material, the CNFs were shortened and agglomerated during the melt-compounding, thus deteriorating the properties of the composites. The study concludes that the pre-fibrillation of pulps had a significant impact on the morphology and properties of the composites. Unexpectedly, the surface-fibrillated pulp, which can be produced cost-effectively using a refiner at an industry scale, was a more suitable form than the CNF as a feed material for melt-compounding in the dry-pulp direct kneading method.

We report an integrated production process that simultaneously nanofibrillates dried pulp and uniformly disperses cellulose nanofibers (CNFs) in resins. Refiner-treated pulp were modified using alkenyl succinic anhydride (ASA) in N-Methyl-2-pyrrolidone (NMP). The ASA treated pulp with DS 0, 0.22, 0.43 and 0.57 was mixed with maleic anhydride-grafted polypropylene (MAPP) powder, CaCO3 and high density polyethylene (HDPE) powder (pulp content: 10 wt%). The mixture was melt-extruded at 140 °C with HDPE. The dumbbell-shaped specimens were prepared using injection molding. The SEM images of refiner-treated pulp (DS 0.43) and previously nanofibrillated CNFs (DS 0.44) using a bead mill as a comparison, both of which were extracted from the melt compounded composites, showed comparable degrees of nanofibrillation. The highest mechanical reinforcing efficiency was obtained at DS 0.43, which was shown to exhibit the most fibrillated morphology. The tensile modulus increased from 1.08 GPa for neat HDPE, to 3.46 GPa. The tensile strength also increased from 23 MPa (neat HDPE) to 56 MPa. The mechanical properties were very similar to the bead mill-fibrillated CNF-reinforced composite. This is the first report of nanofibrillation of dried pulp with uniform CNF dispersion into hydrophobic HDPE. We have termed the process the Pulp Direct-Kneading Method.

Because of their high mechanical performance, high specific surface area, and high aspect ratio, there is a strong interest in cellulose nanofibers (CNFs) as a reinforcing material for plastics. Although three hydroxyl groups per repeating unit exposed on the surface is a unique characteristic of CNFs, an effective chemical treatment to improve the reinforcing efficiency of CNFs for hydrophobic thermoplastic resin has not yet been reported. In this study, six systematically designed aliphatic ester groups with linear, cyclic and branched structures, were incorporated on the surface of CNFs using the hydroxyl groups with a degree of substitution of 0.4. The melt compounding of the esterified CNFs and HDPE was performed at 140 °C using a twin screw extruder followed by injection molding at 160 °C and investigated the CNF dispersibility in HDPE and the CNF reinforcing efficiency in injection-molded HDPE samples. Incorporation of linear long chains results in the best dispersion of CNFs in HDPE compared with cyclic and branched chains, but the latter chains give higher reinforcing efficiencies in Young’s modulus and tensile strength. Especially, the bulky t-butyl group gave the highest reinforcing efficiency. Thus, the structure of ester groups incorporated on the CNFs very much affects on the dispersibility in HDPE, Young’s modulus and tensile strength, and coefficient of thermal expansion (CTE) of the esterified CNFs-reinforced HDPE composites. Addition of pivaloylated CNFs increases the Young’s modulus of HDPE from 1.20 to 3.32 GPa, and the tensile strength from 23.4 to 51.2 MPa. The CTE is 72.5 ppm/K, which is less than one-third that of the HDPE. The high reinforcing efficiency of these composites is partly explained by the formation of the double shish–kebab crystal structure during injection molding identified by the TEM observation.

It is a challenging task to reinforce polyamide 6 (PA6) using nanofibrillated cellulose because the melting temperature of PA6 is high and nanofibrillated cellulose degrade at high temperatures. First, soft wood kraft pulps were acetylated (Ac) to improve the heat resistance. The weight loss temperature of the pulps increased by 31 °C through acetylation (DS = 0.64). It was evident that the melt compounding process using a twin-screw extruder allowed for nanofibrillation of the Ac-pulps. Ac-nanofibrillated cellulose reinforced PA6 showed a high storage modulus, which suggests that the Ac-nanofibrillated cellulose formed a network in the PA6 matrix. The Ac-nanofibrillated cellulose improved the bending modulus from 2.22 GPa (neat PA6) to 5.43 GPa, the strength from 91.2 MPa to 154 MPa, the coefficient of thermal expansion from 110.9 ppm/K to 24.3 ppm/K, and the heat-deflection temperature from 85.7 °C to 166.6 °C. The melt compounding of Ac-pulps with PA6 using a twin-screw extruder facilitates the commercial production of nanofibrillated cellulose reinforced PA6.

Hydrophobic cellulose nanofibers (CNFs) were prepared by surface modification using alkenyl succinic anhydride (ASA). The hydrophobicity of CNFs was varied by changing the degree of substitution (DS) from 0 to 0.83. Modified CNFs were mixed with high-density polyethylene (HDPE) using a twin-screw extruder and the resulting composites were injection molded. The tensile properties initially improved with increasing DS up to ∼0.3–0.5, and then decreased with further substitution. The tensile strength and modulus of 10 wt.% HDPE/CNF composites containing 8.8 wt.% ASA (DS: 0.44) were 43.4 MPa and 1.97 GPa, respectively. These values were both almost 70% higher than those of composites containing unmodified CNF, and 100% and 86% higher, respectively, than those for pure HDPE. X-ray computed tomography measurements showed that CNFs modified with a DS of 0.44 were dispersed uniformly within the resin matrix, whilst unmodified CNFs and those modified with a DS of 0.77 agglomerated within the composites.

The reinforcement of sulfur-vulcanized natural rubber using cellulose nanofibers (CNFs) was investigated. Natural rubber consists mainly of cis-1,4-polyisoprene, and becomes stretchable after vulcanization. Vulcanization was performed via crosslinking with the polyisoprene double bonds, using sulfur and unsaturated fatty acids (oleic acid) incorporated on the CNF surfaces, resulting in highly efficient reinforcement of the CNFs. The Young's modulus of rubber reinforced with 5 wt% oleoyl was 27.7 MPa, i.e., 15 times higher than that of neat rubber, while retaining a strain to failure rate of 300%. The coefficient of thermal expansion of 226.1 ppm K−1 for natural rubber was reduced to 18.6 ppm K−1 after the addition of 5 wt% oleoyl CNFs.

6-Azafulleroid-6-deoxy-2,3-di- O -myristoylcellulose ( 3 ) was synthesized from 6-azido-6-deoxycellulose ( 1 ) by two reaction steps. The myristoylation of compound 1 with myristoyl chloride/pyridine proceeded smoothly to give 6-azido-6-deoxy-2,3-di- O -myristoylcellulose ( 2 ) in 97.0% yield. The reaction of compound 2 with fullerene (C 60 ) was carried out by microwave heating to afford compound 3 in high yield. It was found from FT-IR, 13 C NMR, UV–vis, differential pulse voltammetry (DPV), SEC analyses that compound 3 was the expected C 60 -containing polymer. Consequently, maximum degree of substitution of C 60 (DS C60 ) of compound 3 was 0.33.

In order to elucidate the characteristic features of commercial methylcellulose precisely, O-methylcellulose model copolymers consisting of 2,3,6-tri-O-methylanhydroglucose unit (236MeAGU) and 2-O-methylanhydroglucose unit (2MeAGU) with various composition ratios were synthesized via cationic ring-opening copolymerization of the corresponding glucose orthoester derivatives, subsequent removal of pivaloyl and allyl groups, and methylation. The structure of the obtained copolymers was confirmed by 1H-, 13C-NMR, and FT-IR. Temperature-dependent turbidity measurement verified their thermoresponsive behavior in aqueous solution. The lower critical solution temperature was tuned from 63 to 45 °C above 47 mol-% 236MeAGU content. The hydrophobicity along the cellulose chain was dominant to determine their physical properties. However, the aqueous properties of the MC model copolymers were strongly affected by the slight difference of the composition ratio. The present method would provide further details of the structure–property relationship of O-methylcellulose.

Persimmon (Diospyros kaki Thunb.) accumulates soluble condensed tannin (CT) in fruit which is responsible for its astringency trait. In this study, we analyzed the CT composition in persimmon fruit with phloroglucinol, and identified and characterized novel epigallocatechin-3-O-gallate-phloroglucinol (EGCG-P) adducts as one of the main CT components of persimmon fruit. Analysis with phloroglucinol in persimmon cultivars revealed the different tendencies of the CT composition and component ratio among the four astringency types (PCNA, PVNA, PVA, and PCA), which are categorized by their patterns of astringency loss. The concentration of the main CT component in persimmon fruit, epigallocatechin-3-O-gallate (EGCG), was particularly different among astringency types. Further analysis of the fruit at various maturation stages will help in understanding the different mechanisms of CT accumulation among astringent types. Our results demonstrated that the phloroglucinol methodology is useful for CT composition analysis in persimmon fruit and will contribute to future studies on the astringency trait in this fruit.

It is known that the conventional dehydrogenative polymerization of sinapyl alcohol (S-alc) gave syringyl synthetic lignins (S-DHPs), but in extremely low yields. In this article, to examine the contribution of syringyl quinone methide intermediates (S-QM) on S-DHP production, horseradish peroxidase (HRP)-catalyzed dehydrogenative polymerization of S-alc was carried out in the presence of nucleophilic reagents that promote the rearomatization of S-QM. First, the HRP-catalyzed polymerization of sinapyl alcohol γ-O-β-D-glucopyranoside (isosyringin, iso-S), which allows us to monitor the polymerization process in a homogeneous aqueous phase, was utilized for screening of a nucleophile used as an S-QM scavenger. Monitoring of iso-S polymerization in the presence of various nucleophilic reagents by UV spectroscopy and gel permeation chromatography with photodiode array detection (GPC-PDA) revealed a high ability of azide ion to convert oligomeric S-QM efficiently to S-DHP. Accordingly, azide ion was utilized as an S-QM scavenger in HRP-catalyzed polymerization of S-alc, which resulted in high-yield production of S-DHPs (∼83%), as expected. The 1H-, 13C-, and 2D-HSQC NMR investigations on the resulting S-DHPs clearly demonstrated that azide ion efficiently performed nucleophilic additions to the C-α of S-QM during the polymerization. These results provide experimental proof that the low reactivity of S-QM with nucleophiles (such as water, phenolic, and aliphatic hydroxyl groups) in the conventional polymerization system critically impedes the production of S-DHPs from S-alc.

The incompatibility between cellulose fibers and hydrophobic polymers has presented a major obstacle for the fabrication of composites and nanocomposites. In this study, we applied a one-time grinder treatment to disintegrate chemi-thermomechanical pulp (CTMP) and obtained micro- to nano-meter-sized lamellar or fibrous fragments. The CTMP fragments were composed of cellulose microfibrils with high aspect ratios encased in matrix substances including hydrophobic lignin. Furthermore, we produced compression-molded products from the CTMP fragments by thermally plasticizing lignin without any adhesives or resins. The molded products pressed at 180 °C exhibited a plastic-like gloss on the surface and a high bending strength, 221 MPa, which greatly exceeded that of the conventional plant-based binderless boards. The molded products produced here are a novel form of ideal cellulose nanocomposite, which exploited the inherent compatibility between cellulose microfibrils and matrix substances present in CTMP fragments.

Formaldehyde adsorption and release tests of karamatsu (Larix leptolepis) bark and bark ingredients were performed. Karamatsu bark had good formaldehyde adsorption ability that was better than microcrystalline cellulose. An acetone-soluble fraction from karamatsu bark, which might contain bark tannin, had excellent formaldehyde adsorption ability, and was found to release a trace amount of the adsorbed formaldehyde, suggesting that its formaldehyde adsorption was predominantly due to chemical adsorption. It was confi rmed that the acetone-soluble fraction played an important part in formaldehyde adsorption by karamatsu bark. An acetone-insoluble fraction from karamatsu bark had good formaldehyde adsorption ability as well as the bark, in spite of the residue after the removal of the acetone-soluble fraction.

A synthetic method for obtaining lignin oligomer that contains only the β-O-4 structure is described in detail. This method consists of three reaction steps: (1) the synthesis of t-butoxycarbonylmethyl vanillin (2), (2) the nucleophilic addition oligomerization of compound 2, and (3) the reduction of the oligomeric β-hydroxyl ester. In the first step, compound 2 was synthesized from vanillin in 96.8% yield. In the second step, compound 2 was oligomerized with commercial lithium diisopropylamide (LDA) to obtain oligomeric β-hydroxyl ester (3) in 87.2% yield; the repeating units of this oligomer were joined only by β-O-4 linkages as confirmed by nuclear magnetic resonance (NMR) spectroscopy. In the third step, the oligomeric β-hydroxyl ester (3) was reduced with LiAlH4 to give compound 4 in 42.4% yield. On the basis of NMR, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and gel permeation chromatography analyses of compound 4, it was concluded that compound 4 was an oligomeric lignin model compound containing only β-O-4 interunit linkages. The number average degree of polymerization (DPn) of obtained compound 4 was about 7.0 (Mw/Mn = 1.42). Using this oligomeric lignin model compound, conventional degradation and analytical methods will give new information.

To engineer insect-resistant Solanum plants, a peroxidase C2 gene (prxC2) from horseradish was introduced into Solanum integrifolium Poir. cv. Hiranasu. We produced 77 transgenic Hiranasu plants. Peroxidase expression was confirmed at the transcriptional and translational levels by northern blot analysis and by measuring peroxidase activity, respectively. Feeding test results show that transformant no. 180 is more resistant to corn earworm (Heliothis armigera) and common cutworm (Spodoptera litura) than the wild-type plants. We also found a correlation between insect resistance and lignin content in the transgenic plants. In particular, the lignin content of transformant no. 180 was 30% higher than that of wild-type plants. These results further confirm that peroxidase is functionally expressed in transgenic plants and suggest that the increased lignin content is a basis for the insect resistance in transgenic Hiranasu plants.

A series of novel 4-O-alkoxytrityl chlorides (1) with different chain lengths was synthesized as a novel reagent for obtaining 6-O-alkylated cellulose with high regioselectivity via trityl groups in one reaction step without the use of any protective groups. These chlorides were reacted with methyl Α-d-glucoside, which was used as a model compound, to examine the reactivities toward the primary hydroxyl groups of cellulose to afford a series of 6-O-alkylated methyl Α-d-glucosides in high yields. The product compounds were found to have interesting solubilities and thermal properties. Thus, newly prepared trityl chloride derivatives were found to be useful regioselective derivatization reagents on the primary hydroxyl group in carbohydrates, especially in cellulose.

The structural variety of the condensed tannins (proanthocyanidins) in the fruits of 16Diospyros species are reported. Eleven species contained condensed tannins mostly consisting of a mixture of catechin (CA) and gallocatechin (GCA) repeating units; the other five species did not. The GCA content in the CA-GCA total varied from 0.3% to 84.6%. The number of esterified gallic acid per one flavan repeating unit (degree of galloylation, DG) ranged from 0.01 to 0.89. The GCA content was found to be proportional to the DG values. Thus, 16Diospyros species tested may be classified into five groups by the analytical data of their condensed tannins. It may be interesting to compare their structural characteristics with those of the condensed tannins in other fruits, leaves, woods, and barks from the viewpoint of their biosynthesis and function in the plants.

Chemically synthesized (1 → 5)-β-d-glucofuranan, (1 → 5)-β-d-galactofuranan, (1 → 5)-β-d-xylofuranan, (1 → 5)-α-L-arabinofuranan, natural xylan, and curdlan were sulfated to investigate their inhibitory activities on B16-BL6 lung metastasis and anticoagulant activities. (1 → 5)-β-d-Glucofuranan sulfate, (1 → 5)-β-d-galactofuranan sulfate, xylan sulfate, and curdlan sulfate had binding abilities with B16-BL6 melanoma lysate. The inhibitory activities of sulfated polysaccharides on B16-BL6 lung metastasis selected by heparin binding assay were in the order (1 → 5)-β-d-galactofuranan sulfate > (1 → 5)--β-d-glucofuranan sulfate > xylan sulfate ≫ curdlan sulfate. Furthermore, (1 → 5)-β-d-galactofuranan sulfate, (1 → 5)-β-d-glucofuranan sulfate, and xylan sulfate had not only high inhibitory activity on B16-BL6 lung metastasis but also low anticoagulant activity. The correlation between chemical structure and biological activity is discussed.

Residual wood meal after extraction of milled wood lignin (WMEM) ofEucalyptus globulus was extracted with alkali and LiCl/N,N-Dimethylacetamide (DMAc). These agents dissolve mainly hemicellulose and cellulose, respectively. The extractability of WMEM in alkali solutions was influenced by the degree of swelling of the cellulose. Under good swelling conditions, considerable amounts of cellulose and lignin were extracted with the hemicellulose. Maximum extractability was about 60% of the WMEM under optimum conditions (3 M or 5 M LiOH or 3M NaOH solution). Some portion of cellulose was extracted with LiCl/DMAc at room temperature. Thus, lignin inE. globulus WMEM was divided into three fractions: hemicellulose-lignin fraction, cellulose-lignin fraction, and insoluble-lignin fraction.

The nitrobenzene oxidation method was modified to obtain more reproducible data and more structural information about lignin, not only by gas chromatography (GC) but also by proton nuclear magnetic resonance (1H-NMR) spectroscopy for quantitative determination of the oxidation products and to simplify the procedures. The nitrobenzene oxidation mixture was directly extracted after acidification without preextraction of by-products. The direct extraction made the extractive step easy and gave reproducible data. 5-Iodovanillin was selected as a new internal standard. The reason for this selection was that 5-iodovanillin did not exist in the nitrobenzene oxidation products from any plant species and had an aldehyde group whose peak did not overlap with the other aldehyde peaks on an1H-NMR spectrum. Thus, the use of 5-iodovanillin enabled us to quantifyp-hydroxybenzaldehyde, vanillin, and syringaldehyde in oxidation products on the basis of1H-NMR analysis as well as GC. Furthermore, more information about the condensed structure of lignin was derived by comparing the1H-NMR and GC analyses.

Cellulose isolated from wood is more susceptible than cotton cellulose to homogeneous hydrolysis in phosphoric acid. The influence of carboxyl group introduction at the C6 position on the hydrolysis rate of cellulose in 82.5% phosphoric acid was studied as a model of the oxidation of cellulose during pulping. The rate constant of hydrolysis for dissolving pulp was larger than that of cotton cellulose at temperatures of 25°–35°C. Mercerized cotton cellulose was partially oxidized regioselectively at the C6 position by a free radical system using 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). The oxidized cellulose was obtained at a range of 1.7–12.7 mEq carboxyl content per 100 g of cellulose. The hydrolysis rate of the oxidized cellulose samples accelerated with increasing carboxyl content in the samples.

Heartwood of pernambuco (Guilandina echinata Spreng, synCaesalpinia echinata Lam.), which has been used as material for violin bows, was extracted by soaking in water, and the obtained extractives were analyzed. The main components of the extractives were identified to be protosappanin B and brazilin. In particular, protosappanin B occupied about 40% of the pernambuco extractives. The loss tangent (tanδ) of spruce wood impregnated with protosappanin B decreased markedly, the same as that of specimens impregnated with extractives before being purified. It is expected that protosappanin B can make a contribution to the decrease in tanδ due to impregnation with extractives.

To clarify the lowering mechanism of loss tangen (tanδ) of sitka spruce (Picea sitchensis Carr.) wood impregnated with extractives of pernambuco (Guilandina echinata Spreng. synCaesalpinia echinata Lam.), we examined the vibrational properties of the impregnated wood in relation to the adsorbed water. The results obtained were as follows: (1) The equilibrium moisture content (EMC) of impregnated sitka spruce decreased to some extent compared with untreated wood. (2) Frequency dependencies of tanδ a about 400–8000Hz showed that impregnated wood has much lower tan δ than untreated wood at around 9% mois ture content (MC), except for the high-frequency region. At high relative humidity, impregnated wood has a minimum tanδ (at around 4000Hz); and at other frequency ranges the tanδ of impregnated wood did not differ considerably from that of untreated wood. (3) The apparent activation energy of the mechanical relaxation process (ΔE) concerned with adsorbed water molecules was higher for impregnated specimens than for untreated ones at moderately high relative humidity, whereas at high relative humidity the difference was not observed. Based on these results, it is thought that the tanδ of impregnated wood decreased at low rela tive humidity because of the formation of direct hydrogen bonds between impregnated extractives and wood components. However, when the specimen is at higher relative

Sitka spruce (Picea sitchensis Carr.) was treated with water-soluble extractive components of pernambuco (Guilandina echinata Spreng. syn Caesalpinia echinata Lam.) by two methods: impregnation under evacuation using an aspirator and repetitive surface application using a brush. The influence of these treatments on the vibrational properties were examined. The loss tangent (tan δ) of the impregnated specimen decreased, up to nearly a half of its original value, with increasing weight gain. It is suggested that the decrease in tan δ results from impregnation of the extractive components into the amorphous region of cell walls, forming secondary bonds between matrix substances. The surface application of the extractive components, on the other hand, hardly brought about the desirable change in vibrational properties.

The impregnation of various simple phenolic and natural polycyclic compounds into wood was investigated from the viewpoints of vibrational property and dimensional stabilizing effect. When simple phenolic compounds were impregnated, the loss tangent (tan δ) in the longitudinal direction increased linearly with increasing weight gain. Meanwhile, among the natural polycyclic compounds hematoxylin decreased the tan δ drastically by impregnation. It was suggested that the five hydroxyl groups and the pyran ring oxygen in the hematoxylin molecule contribute to formation of the crosslinkage-type hydrogen bonds between wood components. The rigidity of hematoxylin molecules may also be important. By impregnation of about 10% catechol, resorcinol, and saligenin, a 40% level of antiswelling efficiency (ASE) was attained, although a significant dimensional stabilizing effect was not observed after impregnation of natural polycyclic compounds.

The reaction of (+)-catechin with formaldehyde vapor was investigated as a model reaction of formaldehyde adsorption of (+)-catechin. It was found by H nuclear magnetic resonance spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and gel permeation chromatography of the product that the vapor reaction of (+)-catechin with formaldehyde without a solvent or a catalyst proceeds via methylolation, condensation, and polymerization. This is the same as the reaction in a solvent in the presence of an acid or a base. The formation of polyoxymethylenes such as paraformaldehyde was not confirmed.

The enzymatic dehydrogenative polymerizations of monolignols, mainly using horseradish peroxidase (HRP)/hydrogen peroxide as a catalytic system, has been widely used as a model to study lignifi cation, yet there still remain several points to be clarifi ed. One of them is the peculiar behavior of sinapyl alcohol (SA) in the in vitro polymerizations. Many researchers have reported that enzymatic dehydrogenative polymerizations of SA afforded synthetic lignin (dehydrogenation polymer: DHP), but in extremely low yields, whereas the polymerizations of coniferyl alcohol (CA) or p-coumaryl alcohol (PA) gave their DHPs in high yields. Enzymatic dehydrogenative polymerizations of monolignols proceed mainly by three steps: (1) radical formation by enzymatic dehydrogenation of phenolic hydroxyl groups; (2) radical coupling; (3) nucleophilic addition of nucleophiles to the quinone methide intermediates (QMs), re sulting in the reproduction of phenolic compounds for subsequent oxidative couplings. The polymerization of SA is shown in Figure 1. Until now, the problems regarding the polymerizations of SA have been mainly discussed in terms of the reaction steps (1) and (2): the low reactivity of HRP to SA and preferential b-b coupling reactions to b-O-4. However, there is no report focused on reaction step (3) concerning the low polymerizability of SA. Brunow et al. reported that syringyl-type (S-type) quinone methide model compound was signifi cantly less

Diospyros species distributed widely in Thailand were classified into four ecotypes, according to their habitat; constantly humid area, alternately dry and wet area, mountainous cool area and all area. Some of them inhabit near dwelling areas or in the paddy field in the village. The young fruit is covered with dense pubescence in most species. The size, shape, and color of mature fruit greatly vary greatly with the species. In most species, the mature fruit has a soft pulp and hard skin. The fruit of six species has been used for dying. Four species produce edible fruits, with color and flavor favorable for breeding of edibleDiospyros species. The fruit of some species contains some chemicals useful as fish poisoning or of medicines, although the active components have not yet been identified. The edible fruit contained many tannin cells, but the fruit used as fish poisoning and medicines had only a few.

Rubiadin (4) (1,3-dihydroxy-2-methylanthraquinone), which is one of the natural dyes from the roots of Rubiaceae, was synthesized from phthalic anhydride (1) and 2,6-dihydroxytoluene (3) by two reaction steps, that is, a Friedel-Crafts reaction with AlCl3 and a cyclization with H2SO4/HBO2. Microwave heating resulted in remarkable acceleration of the reaction rate in the first reaction, and had an effect in reducing the reaction time and increasing the yield of rubiadin (4) in the second reaction.

Right-handedness derived from bisporphyrins attached to a cellotriose backbone at O-6 and O''-6 positions is revealed for the first time. This cellotriose is proposed as a model of alternatingly functionalized cellulosics, which have promising properties for applications in optoelectronics and molecular receptors owing to the chirality and rigid backbone effects.

The authors studied acetylation of bacterial cellulose (BC) nanofibers to widen the applications of BC nanocomposites in optoelectronic devices. The slight acetylation of BC nanofibers significantly reduces the hygroscopicity of BC nanocomposites, while maintaining their high optical transparency and thermal stability. Furthermore, the degradation in optical transparency at elevated temperature (200°C) was significantly reduced by acetylation treatment. Therefore, the acetylation of bionanofibers has an extraordinary potential as treatment for property enhancement of bionanofiber composites.

The degradation pathway for the most important β-O-4 lignin substructure with a white rot fungus, Phanerochaete chrysosporium, was investigated, and the following conclusions were the β-O-4 substructure was degraded to a formyl group via a glycerol group, b) Arylglycerol was formed by the cleavage of the β-O-4 substructure without involvement of the hydroxylation reaction at Cβ. c) 18O was not incorporated from 18O2 into arylglycerol nor phenol liberated by the degradation of the β-O-4 substructure, but was incorporated into the benzyl alcohol derivative formed by Cα-Cβ cleavage, d) Two alternative degradation pathways of the β-O-4 substructure, a pathway via arylglycerol and direct oxygenative Cα-Cβ cleavage, are proposed.

Trimeric lignin model compounds, arylglycerol-β-syringaresinol ethers, were incubated with Fusarium solani M-13-1 in basal salts medium with shaking. From the culture filtrates, degradation products were isolated and characterized spectroscopically. Based on the degradation products of guaiacylglycerol-β-syringaresinol ether (II), the following reactions were found to occur; 1) oxidation of benzylic position (α′′) and subsequent ring opening of the syringaresinol side chain, 2) cleavage of alkyl-aryl C-C bonds (Cα-C1 and Cα′′-C1′′) of both arylglycerol and syringaresinol portions, and 3) splitting of the alkyl-aryl ether bond (Cβ-O-C4′). In the case of syringlyglycerol-β-syringaresinol ether (III), preferential oxidation of benzylic position (α) of the arylglycerol moiety was seen. The former two reactions were found to be catalyzed by the fungal phenol oxidizing enzymes.

Degradation of β-O-4 and β-1 lignin substructure model dimers under 18O2 in a ligninolytic culture of a white rot fungus, Phanerochaete chrysosporium, was investigated. 18O2 was incorporated into Cα, in the Cα-Cβ cleavage of the β-O-4 substructure, while 18O2 was incorporated into Cβ, but not into Cα, in the Cα-Cβ cleavage of the β-1 substructure.