Separation of aqueous ethanol solutions by pervaporation using graft-coplymerized cellulose membranes was investigated on the basis of the results obtained previously. Polyanions, polycations and polybetains were introduced into cellulose membranes by grafting. These chemically modified cellulose membranes were expected to have selective separation functions of the water/ethanol mixtures due to high affinity to the solutions . Permeation rates (flux) and separation selectivity of the prepared membranes were evaluated by the pervaporation experiments. High permeation rates were obtained for the membranes with increasing pervaporation temperature. Relationships between permeation rate and separation selectivity obtained for the membranes were well explainable in terms of the molecular diffusion mechanism in this separation system. The high separation of various ceuulose-related membranes obtained in this study indicates the potentials of further development of the pervaporation technique.
The purpose of this study was to clarify the effect of hyaluronan (Hya) and sulfated hyaluronan (SHya) on rat calvarial osteoblast (rOB) cells proliferation and differentiation in vitro. rOB cells were cultured in the presence of Hya with different molecular weights (0.2, 2, 30, 90, 120 x 104) for 10days. Hya did not affect the proliferation of rOB cells. However, SHya suppressed the proliferation of rOB cells. The alkaline phosphatase (ALPase) activity of rOB cells cultured with SHya for 10 days was significantly enhanced in comparison with control (in the absence of polysaccharides) and with Hya. Hya suppressed the ALPase activity of rOB cells. As a result, SHya can control rOB cells proliferation and differentiation. SHya suppressed the rOB cells proliferation in a few culture days and promoted the differentiation. It was suggested that these effects were based on the sulfate groups of SHya. Therefore, it is considered that SHya is useful for the biomedical material, which promotes the differentiation of rOB cells.
Hygienic antistatic cotton fabrics have been developed with applications in antistatic carpets, filters and hygienic hospital apparels. Cotton fabrics have been impregnated with conducting polymer, viz:- polypyrrole in various ratios. These fabrics show improved electrical conduction by about 3 - 8 orders of magnitude. Since the electrical conduction required for antistatic applications is only marginal, small amounts of these conducting polymers were found to be sufficient to give good antistatic properties. Also these fabrics were tested for their antimicrobial properties, which were found to be very good. These fabrics have also been demonstrated to be useful as heating pads and carpets.
The process of alkaline hydrolysis of polyester (PET) fabric under high-pressure conditions of over 100 MPa was examined. The decomposition of the PET fabric was accelerated with increased pressure. The addition of surfactant also enhanced the reaction rate when the concentration was more than 1.0 g/l. At high surfactant concentrations, the acceleration effect plateaued. The activation volume hardly changed with the concentration of surfactant.
Alkali-retting was applied to kenaf bast ribbons and the mechanical properties and the structure of the retted fibers were investigated. In order to produce the fibers with preferable surface smoothness, the retting should be made at the NaOH concentration higher than 4 %. The tensile properties, however, showed a maximum at the NaOH concentration of 1 %, and decreased with increasing NaOH concentration. It seems difficult to prepare the fibers with preferable surface smoothness without loosing tensile strength only through the alkali-retting.