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Volume 51, Issue 3
Displaying 1-12 of 12 articles from this issue
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Kunio Nakamura, Yuko Nishimura, Tatsuko Hatakeyama, Hyoe Hatakeyama1995 Volume 51 Issue 3 Pages 111-117
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSIn this study, from the viewpoint of biodegradable polymers and waste disposal, polyurethane (PU) foams and films containing sericin were prepared from sericin and diphenylmethane diisocyanate (MDI). Polyethylene glycol (PEG, diol type) and polypropylene glycol (PPG, triol type) were used as a part of the polyol. Mechanical and thermal properties of PU's containing sericin were measured by tensile test and thermal analysis. Sericin could be used as a polyol of PU's and the strength and the glass transition temperature of PU films containing sericin increased with increasing sericin content. The strength of PU foams depended strongly on their apparent density. From the dynamic mechanical analysis (DMA), loss modulus (E") and tan δ curves showed three peaks, α, β, γ in the region from high to low temperatures. The α and β peaks which are assigned to the main chain motion and local mode motion shifted to the higher temperature region with increasing sericin content. The γ peak was almost constant at -130°C.View full abstractDownload PDF (400K) -
Preparation and Physical Properties of Polyurethanes from Oligosaccharides and Lignocellulose SystemTadaaki Tokashiki, Shigeo Hirose, Hyoe Hatakeyama1995 Volume 51 Issue 3 Pages 118-122
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSPolyurethane (PU) foams were prepared by following procedure. Power samples of bagasse, pineapple and cellulose were mixed with polyethylene glycol (molecular weight 200). The obtained mixtures were reacted with diphenylmethane diisocyanate in the presence of small amounts of water, di-n-butyltin dilaurate, silicone surfactant. Thermal and mechanical properties of these PU's were studied by differential scanning calorimetry, thermogravimetry and compression tests. The glass transition temperature increased with increasing bagasse, pineapple bran and cellulose powder contents. The thermal decomposition temperature was almost constant and regardless of bagasse, pineapple bran and cellulose powder contents. Stress and compression modulus of PU foams decreased slightly with increasing contents of ground plant materials, although mechanical properties of PU foams molasses increased with increasing molasses contents in PU's.View full abstractDownload PDF (786K) -
Tsutomu Nakagawa, Akihito Kanemasa1995 Volume 51 Issue 3 Pages 123-130
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSRemoval and enrichment of chlorinated hydrocarbons, such as 1, 1, 2-trichloroethane, TCE, trichloroethylene, TCET, and tetrachloroethylene, TECET, from their diluted aqueous solutions by pervaporation were investigated. As novel membranes with high permselectivity for those solvents, copolymers composed of (trimethylsilyl) methyl methacrylate, TMSMMA, which forms a glassy polymer, and n-butyl acrylate, n-BA, which forms rubbery polymer, were synthesized by radical polymerization. The characterization of copolymers was carried out by FT-IR, 1HNMR, WAXD and DSC. The film formation of the copolymers was better. The effect of molar ratio of TMSMMA/ n-BA on the flux of TCE and the separation factor, α (TCE/water) was clarified. The glass transition temperatures of the copolymers decreased with the increase of n-BA content, which gave the high segmental mobility and thus high diffusivity. The copolymeric membrane containing about 70 mol% of n-BA showed the highest separation factor, 600-1000, for TCE. The high permselectivity for the chlorinated hydrocarbons by the copolymeric membranes was mainly attributed to high partition coefficient for the chlorinated hydrocarbons.View full abstractDownload PDF (530K) -
Atsuyoshi Nakayama, Norioki Kawasaki, Noboru Yamamoto, Ioannis Arvanit ...1995 Volume 51 Issue 3 Pages 131-136
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSBiodegradability of poly (L-lactide-co-ε-caprolactone) s was evaluated with both enzymatic and non-enzymatic hydrolysis. The hydrolysis was carried out in phosphate buffer (pH 7.0) at 37°C for 24h and the enzymes used were lipases from Rhizopus arrhizus, Rhizopus delemar, and Candida cvlindracea. The hydrolyzability of these polymers was evaluated with measurement of TOC values (total organic carbon concentration) which show the amount of the hydrolyzed water-soluble products. The copolymers were synthesized by ring-opening polymerization using tin (II) octanoate as initiator. Although poly (L-lactide), poly (ε-caprolactone) and their random copolymers were hydrolyzed with all three above mentioned lipases, Rhizopus arrhizus and Rhizopus delemar lipases proved to be the most effective. The extent of enzymatic hydrolysis was considerably affected by copolymer composition. The copolymer, which showed the highest susceptibility to hydrolysis, was the one containing 82 mol% ε-caprolactone unit. The polymers were also non-enzymatically hydrolysed (70°C, 1 week) and the results were similar to those of enzymatic hydrolysis showing clearly the influence of copolymer composition on the TOC results. However, TOC measurements showed that the L-lactide rich copolymers, and in particular the one with 80 mol% lactide content, were more susceptible to hydrolysis. These results suggest that poly (ε-caprolactone) can be easily degraded with lipase, whereas poly (L-lactide) can be also degraded with simple hydrolysis. ε-Caprolactone rich oligomers, 6-hydroxycaproic acid, and lactic acid were identified with NMR as the main products of hydrolysis.View full abstractDownload PDF (390K) -
Masao Kunioka1995 Volume 51 Issue 3 Pages 137-142
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSHydrolytic and enzymatic degradation processes of hydrogels prepared by γ-irradiation from microbial poly (ε-lysine) (PL) were studied. Hydrolysis studies on PL hydrogels were carried out in deionized water at 40, 75, and 95°C. PL hydrogel, which was prepared with 100 kGy γ-irradiation dose and 5 wt% PL concentration. was degraded by only 2% at 40°C for 17 hours, and degraded by 14% at 75°C for 13.5 hours. As the heating temperature was increased, the degradation rate was increased. The specific water content (wt. of absorbed water/wt. of dry gel) was increased with the progress of hydrolytic degradation, The rate of hydrolytic degradation of heterogeneous opaque PL hydrogel (≤ 3 wt% PL concentration) was slower than that of homogeneous transparent PL hydrogel. The thermal stability of PL hydrogel was found to be dependent on the structure of the gel. The enzymatic degradations of PL hydrogels were studied at 40°C and pH 7.0 in the 25 mM phosphate buffer with Protease A produced from Aspergillus oryzae. PL hydrogels were degraded by 20-60% for 17 hours by Protease A. The rate of enzymatic degradation of PL hydrogel was much faster than the rate of simple hydrolytic degradation. The enzymatic degradation occurred at the surface of the PL hydrogel. The surface erosion by Protease A was confirmed by monitoring the time-dependent changes in the specific water content of the PL hydrogel.View full abstractDownload PDF (417K) -
Noriyuki Morohoshi, Shigeo Hirose, Hyoe Hatakeyama, Tadaaki Tokashiki, ...1995 Volume 51 Issue 3 Pages 143-149
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSBiodegradability of polyurethane (PU) foams derived from molasses was investigated by a soil burial method. The weight loss of samples (5×5×1cm) was determined within about 3% of analysis error using a new developed method in this paper, correcting the adsorbed soil into the polyurethane foams. The soil burial experiment was carried out at two different test fields, nursery garden (Byoho) and Hakyuchi experimental station (Hakyuchi) in Tokyo University of Agric. & Technol. The soil of nursery garden could have higher degradation activity for molasses-PU foams than that of Hakyuchi. The difference of weight loss between both soils was about 10%.
The PU foams derived from molasses had higher degradability than that of Sugi wood and lower than that of Buna wood. Conclusively they have similar degree of biodegradability to natural high polymers such as woods.
The sucrose incorporated into the molasses-PU foam was converted at 80% to cabon dioxide during 35 days in Byoho soil. It was assumed that the molasses was degraded at the first stage and promoted the degradation of molasses-PU foam.
Some microorganisms degrading the urethane linkages were isolated and determined to be a bacterum, and two actinomyces from the soils. The detection of these microorganisms indicates the biodegradation of the urethane bonds in the nature.
These results suggest that the biodegradability of PU foams is accelerated by the incorporation of the molasses, and the PU foams are degraded and converted to the chemical components (polyol and isocyanate units) constituting the PU foam in the natural soils.View full abstractDownload PDF (2271K) -
Tetsuya Tamura, Jun Fujimoto1995 Volume 51 Issue 3 Pages 150-155
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSThermosetting resins reinforced with fibers have been widely used, due to their good mechanical properties, and good resistance to chemical agents. During the same time, the increase in manufacturing has led to the production of more and more waste quantities. Such waste is difficult to dispose safely because of its nature. Materials designed for easy recycling are strongly required in order to reduce the adverse load on the environment.
New kind of carbon fiber reinforced plastics have been developed in the present work to improve both mechanical properties and recyclability. These materials were fabricated by sandwiching the vibration damping-material between layer interfaces in CFRP.
This article presents mechanical properties and ability to disassemble for CFRP/damping-material laminates, with special emphasis on the effect of employing damping-material interleaves.View full abstractDownload PDF (1761K) -
Hiroshi Mitomo1995 Volume 51 Issue 3 Pages 156-160
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSCrystallization and nucleation behavior of microbial poly (3-hydroxybutyrate) and poly (3-hydroxybutyrate-co-3-hydroxyvalerate) were investigated by differential scanning calorimetry. The polymers mixed with talc as a nucleating agent showed promotion of crystallization of the polymers, while the addition of saccharin hardly promoted crystallization. However, melting points and long periods of these polymers crystallized isothermally after mixing with talc and saccharin, decreased considerably. The depression in melting points and long periods of the polymers mixed with saccharin was larger than that mixed with talc, implying that saccharin was included more easily within the polymer crystal playing the role of diluent. The concentration of around 4% is most appropriate to reveal typical effect of nucleating agents without severe deterioration of mechanical properties. Large spherulites were formed in plain polymers and those mixed with saccharin, whilst extremely small spherulites were formed in the polymers mixed with talc.View full abstractDownload PDF (866K) -
[in Japanese]1995 Volume 51 Issue 3 Pages P88-P92
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (964K) -
[in Japanese]1995 Volume 51 Issue 3 Pages P93-P95
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (2238K) -
[in Japanese]1995 Volume 51 Issue 3 Pages P96-P100
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (1483K) -
[in Japanese]1995 Volume 51 Issue 3 Pages P101-P105
Published: March 10, 1995
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (3044K)
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