Showing papers by "Shiro Saka published in 1998"

Antimicrobial TMSAH-Added Wood-Inorganic Composites Prepared by the Sol-Gel Process

Abstract: To add stable antimicrobial properties to woods, an amphoteric sterilant, 3-(trimethoxysilyl))propyl (carboxymethyl) decylmethyl ammonium hydroxide inner salt (TMSAH) was applied to the sol-gel process, as SiO 2 wood-inorganic composites were prepared. The obtained TMSAH-added SiO 2 composites could reveal the high antimicrobial activities against a fungal attack by brown-rot fungi, but their activities against white-rot fungi were somewhat less. This result would be, therefore, due to the amphoteric nature of the TMSAH sterilant, which was stable under acidic conditions. However, the addition of property-enhancer, 2-haptadecanuorooctylethyltrimethoxysilane (HFOETMOS) to the above reaction system could provide HFOETMOS-(TMSAH-SiO 2 composites with water-repellency and its water-repellent property has improved antimicrobial activities in the composites, against both brown-rot and white-rot fungi.

SiO2-P2O5-B2O3 wood-inorganic composites prepared by metal alkoxide oligomers and their fire-resisting properties

Abstract: SiO 2 -P 2 O 5 -B 2 O 3 wood-inorganic composites from metal alkoxide monomers revealed a high fire-resistance, whereas these composites have some problems in the stabilities of P 2 O 5 and B 2 O 3 gels as well as environmental safety for their preparation. Therefore, some silicon alkoxide oligomers with ethylphosphite residue and/or boric hydroxide residue were prepared and applied for SiO 2 -P 2 O 5 -B 2 O 3 wood-inorganic composites preparation. The obtained composites could have high fire-resistance and prevent these gels from leaching. Additionally, the prepared oligomers are non-toxic so that the environmental safety for their preparation was achieved. By adding 2-heptadecafluorooctylethyltrimethoxysilane (HFOETMOS) to the oligomer reaction system, the obtained composites could improve further the anti-leachability of P 2 O 5 and B 2 O 3 gels.

Cellulose triacetate prepared from low‐grade hardwood dissolving pulp and its insoluble residues in acetylation mediums

Abstract: As cellulose triacetate is prepared from low-grade hardwood dissolving pulp, a considerable amount of the insoluble residue was present in the acetylation medium of the acetic acid/acetic anhydride/sulfuric acid system. The characterization of this residue indicated that the insoluble residue is composed of cellulose triacetate and xylan diacetate, retaining a fiber structure of swollen form. To reduce the insoluble residues, reaction conditions for acetylation were investigated. As one of the remedies of reducing the insoluble residues, 17 different solvents were selected to add to the acetylation medium, and among these, dichloroacetic acid was found to be very effective for its reduction. The obtained cellulose triacetate could then reveal good thermal properties similar to that from high-grade dissolving pulps. Therefore, acetylation systems with an addition of an appropriate solvent can have a potential to industrially manufacture a high-quality cellulose triacetate from even low-grade hardwood-dissolving pulps, as observed in low-grade softwood-dissolving pulps. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 289–297, 1998

Method for preparing antibacterial/antifungal inorganic matter-composited wood

Abstract: An antibacterial/antifungal inorganic matter is composited with wood by impregnating wood with a solution containing a silicon alkoxide and an antibacterial/antifungal organic silicon compound having a hydrolyzable alkoxysilyl group, and subjecting the silicon compounds within the cell walls (inter- and intracellular) spaces to hydrolysis at various temperatures and polycondensation. The same is prepared by treating wood with a siloxane oligomer and curing the oligomer. The antibacterial/antifungal component is prevented from being leached out.

Effects of solvent addition to acetylation medium on cellulose triacetate prepared from low‐grade hardwood dissolving pulp

Abstract: As cellulose triacetate was prepared from low-grade hardwood-dissolving pulp, a considerable amount of the insoluble residue was present in the acetylation medium of the acetic acid/acetic anhydride/sulfuric acid system, and it consisted mainly of cellulose triacetate (CTA) and xylan diacetate (XDA). As one of the remedies for reducing the insoluble residue, a solvent was added to the acetylation medium and the effects of the solvent addition on the amount of insoluble residue formed were studied. To do so, 17 different solvents were selected so as to cover a wide range of solubility parameters. The obtained results clearly indicated that the addition of the solvent affects the amount of insoluble residue and that, excluding dichloroacetic acid, nitromethane was effective for its reduction, but that neither methylene chloride nor nitroethane were in spite of their effectiveness for softwood-dissolving pulp, which would be due to the intrinsic properties of XDA on the solubility in the acetylation medium. A new acetylation system with such an appropriate solvent would, therefore, provide a clue as to an industrial usage of the low-grade hardwood-dissolving pulps for cellulose acetate production. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1445–1449, 1998

Removal of toxic substances of chloroform and benzene by carbonized woody materials

Abstract: In a global expansion of environmental pollutions, trihalomethanes in water and aromatic toxic substances in air are both increasing. In this study, therefore, an effort has been made to develop carbonized woody materials to remove specifically these polluting materials and explore a potential of developing more functionalized new woody carbonized materials. It was found by elemental analysis that carbonized woody material prepared under hydrogen gas flow was more reduced, compared with that under nitrogen gas flow, particularly over 550°C. Both carbonized woody materials were decreased in vapor adsorption of water with increasing the temperature, whereas adsorption of chloroform and benzene was instead improved and over 550°C, carbonized woody materials under hydrogen gas flow was superior to that under nitrogen gas flow in their adsorption. Carbonized woody materials with these characteristics were found to adsorb chloroform in water and benzene in atmosphere effectively. These lines of evidence would support a concept that hydrogenative reduction of woody materials would be effective to enhance its adsorptivity against chloroform in water and benzene in atmosphere.

Methods for preparing antibacterial/antifungal compositions of wood with inorganic matter, and products thereof

Abstract: An antibacterial/antifungal inorganic matter is composited with wood by impregnating wood with a solution containing a silicon alkoxide and an antibacterial/-antifungal organic silicon compound having a hydrolyzable alkoxysilyl group, and subjecting the silicon compounds within the cell walls (inter- and intracellular) spaces to hydrolysis at various temperatures and polycondensation. The same is prepared by treating wood with a siloxane oligomer and curing the oligomer. The antibacterial/antifungal component is prevented from being leached out.