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Volume 70, Issue 12
Displaying 1-11 of 11 articles from this issue
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Comprehensive Papers
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Toshihiko OOI, Ken’ichiro MATSUMOTO, Ryousuke KADOYA, Seiichi TA ...2013 Volume 70 Issue 12 Pages 675-683
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSThis review touches on recent trials for producing microbial polyhydroxyalkanoates (PHAs), which are used as a bio-based plastic, from renewable and non-edible lignocellulosic biomass. Lignocellulose is composed of cellulose, hemicellulose and lignin, which form a persistent complex. Thus, for the efficient saccharification of lignocellulose, the physical/chemical processes for removing lignin and unstiffening cellulose fibers are required. The obtained sugar is typically a mixture of glucose and xylose, and contains a certain inpurity derived from lignocellulose and/or byproduct generated during pretreatment and subsequent saccharification processes. The microbes used for PHA production need to utilize the mixed sugar and to be resistant to the impurities. This review introduces several examples for addressing this issue. Moreover, an important direction is to design the polymer with better properties. Metabolic and enzyme engineering are powerful tools to biosynthesize various useful polymers from non-related sugar carbon sources. In particular, microbial production of lactate-based polymer from xylose is a potent platform.View full abstractDownload PDF (951K) -
Tetsu YONEZAWA2013 Volume 70 Issue 12 Pages 684-692
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSThe application of a bio-polymer, gelatin, as a material for copper fine particles, used for electronics parts, is described. Gelatin is well-known as a good stabilizer of metal nano- and fine particles. However, gelatin has not been frequently applied to such materials. According to the properties of surface coatings by gelatin, these copper fine particles are not easily oxidized. They could also be applied as the material for the inner electrodes of ceramic condensers. Such applications of bio-polymers can be one good example for reaching a sustainable society.View full abstractDownload PDF (1311K)
Original Papers
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Ikki KATADA, Masahito TOYONAGA, Keisuke GOTO, Fumihiro KOBAYASHI, Hibi ...2013 Volume 70 Issue 12 Pages 693-696
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSIt is known that the stability of polypropylene (PP)-based materials is greatly affected by their higher-order structures. In this paper, we examined the influences of spherulite structure and inorganic filler on the dispersion of stabilizers and the degradation spreading with the aid of IR microscopy. It was found that stabilizers tend to concentrate outside of spherulite structure, and that such a heterogeneous dispersion became more prominent with increasing spherulite size. Oxidative degradation concentrated at chemically and mechanically weak spherulite borders, and was faster for larger spherulites. The addition of inorganic filler promoted the volatilization of stabilizers from poorly connected interfaces between PP and filler, thus reducing the lifetime of PP. In this way, the present paper describes the significance of higher-order structures and interfaces for the degradation and stabilization of PP-based materials.View full abstractDownload PDF (628K) -
Hiroshi NONAKA, Wakana HANAMOTO, Masamitsu FUNAOKA2013 Volume 70 Issue 12 Pages 697-703
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSLignophenol, a lignin-based functional polymer, has a higher protein adsorption capacity than other conventional lignins. However, it has been difficult to find a clear correlation between the primary structure (e.g. functional groups, molecular weight) and the adsorption capacity. In this study, lignocresol and bovine serum albumin (BSA) were selected as a standard lignophenol and protein, respectively. We found that aggregation of lignocresol powder in aqueous solution has little influence on BSA adsorption. In contrast, pressing of lignocresol significantly decreased the adsorption capacity probably because lignocresol molecules were packed densely by intermolecular van der Waals force and hydrogen bonding. Precipitation in nonpolar solvents also led to a decreased adsorption capacity, suggesting that molecular rearrangement in various poor solvents has an effect. The protein adsorption capacity of lignophenol can be controlled by changing its higher order structure using these easy methods.View full abstractDownload PDF (890K) -
Kentaro NAGASHIMA, Nobuhiro KIHARA2013 Volume 70 Issue 12 Pages 704-711
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSCopolymers of methyl 4-vinylbenzoate or methyl acrylate with styrene were converted to hydrazide-containing polymers by refluxing with hydrazine monohydrate. The resulting polymers were crosslinked by the oxidative coupling reaction of hydrazide with oxone or diacetoxyiodobenzene. The crosslinked polymers were decrosslinked by the oxidative degradation of the diacylhydrazine linkage with sodium hypochlorite. The carboxyl group produced by decrosslinking was converted to the methyl ester group by the treatment with trimethylsilyldiazomethane to obtain the original copolymers. The recycling process could be repeated.View full abstractDownload PDF (809K) -
Aya TOMINAGA, Hiroshi SEKIGUCHI, Ryoko NAKANO, Shigeru YAO, Eiichi TAK ...2013 Volume 70 Issue 12 Pages 712-721
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSRecycled plastics are considered to have worse mechanical stability and less durability. Usually, the reason for above phenomena was thought to be caused by chemical degradation. However, we recently found that pre-consumer polypropylene was not chemically degraded and had almost the same molecular properties as virgin polypropylene. But the inner structure of virgin and recycled samples are very different (virgin: very smooth, recycled: very rough), and the mechanical properties of thin films are also very different (virgin: ductile, recycled: brittle). From the UV degradation properties, we had concluded that the difference of the mechanical properties had come from the difference in number of adhesion sustaining molecules that connect the grains (crystals of polypropylene). This result suggests that, if we can increase the number of the adhesion sustaining molecules, we can improve the mechanical properties and the durability of recycled polypropylene. In this time, we applied various thermal treatments for recycled pre-consumer polypropylene and found that we could obtain properties similar to virgin polypropylene. These methods are thought to be a promising way for successful recycling plastics.View full abstractDownload PDF (1272K) -
Mitsuru AOYAGI, Kodai MURAI, Masamitsu FUNAOKA2013 Volume 70 Issue 12 Pages 722-730
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSThree esters of Hinoki cypress (Chamaecyparis obtusa)-lignophenol(p-cresol type, HCLC), acetate (HCLCAc), benzoate (HCLCPh) and oxyallylcarbonate (HCLCalloc), were investigated using FT-IR, 1H NMR, SEC, TGA, TMA and DSC. These esters demonstrated larger Mw than lignophenol (LP) due to electrostatic interaction and inter- and intra-molecular interactions of ester side chains. Both TGA and TMA showed higher thermal stability and good plasticity at a lower temperature than HCLC. The thermal stability of esters were evaluated using Ozawa plots of the TGA analysis data. Improvement of these properties depends on both ester linkages and side chains of esters. Moreover, DSC showed clear Tg on the first run without exo-thermal peaks, that means no thermal degradation. These results show that it is possible to control the properties of lignophenol esters and to investigate unknown thermal properties of main chains in HCLC based on native lignin.View full abstractDownload PDF (781K) -
Idzumi OKAJIMA, Kaori WATANABE, Takeshi SAKO2013 Volume 70 Issue 12 Pages 731-737
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSWhen nylon 6 is decomposed for 20 minutes at 350°C, and 16.5 MPa of saturated vapor pressure in subcritical water, the decomposition ratio of nylon 6 was 99.1% and the yields of ε-caprolactam and ε-aminocaproic acid were 69.2% and 13.4%, respectively. In subcritical water, the reversible reaction between ε-caprolactam and ε-aminocaproic acid occurs and their equilibrium molar ratio was about 10:1 at 300°C and with saturated vapor pressure. Furthermore, ε-aminocaproic acid decomposed to a byproduct. The calculated reaction time dependences of the yields of ε-caprolactam and ε-aminocaproic acid and the amount of the remaining nylon 6 for the whole hydrolysis route in subcritical water, agreed well with the experimental data.View full abstractDownload PDF (751K) -
Yoshio UEMICHI, Yoshimi OCHIAI, Sachie TA, Nobuhito YAMADA, Yohei KATS ...2013 Volume 70 Issue 12 Pages 738-743
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSDegradation of low-density polyethylene (LDPE) containing small amounts of other plastics, which are polyvinyl chloride (PVC), polyamides 66 and 6 (PA66 and PA6), polyethylene terephthalate (PET) and polystyrene (PS), has been investigated using gallium zeolite catalysts. Gallium silicate catalyst showed a high activity for converting LDPE into aromatic hydrocarbons, and its catalytic activity was hardly influenced by the presence of PET and PS in the plastic mixtures. However, PVC and PA66 mixed with LDPE caused significant reduction of the catalytic performance probably because of deposition of Cl- and N-containing compounds and more formation of coke on the catalyst surface. Ga/H-ZSM-5, newly prepared in this work, was found to be promising as a catalyst for producing aromatics from degradation of PVC- and PA66-containing LDPE. The catalyst has a high potential for use in advanced chemical recycling of waste polyolefins.View full abstractDownload PDF (750K) -
Nobuyoshi NOMURA, Jun HASEGAWA, Hisanori KISHIDA2013 Volume 70 Issue 12 Pages 744-752
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSThree polymer-supported homosalen ligands for the stereoselective polymerization of racemic lactide were synthesized: the Ph-substituted and tBu-substituted ligand on the Merrifield resin and the tBu-substituted ligand on the Wang resin. The corresponding aluminum catalyst was prepared by mixing with Et3Al in toluene at 70°C. Excess Et3Al was efficiently removed together with the solvent from the catalyst mixture. All of the catalysts stereoselectively polymerized racemic lactide to afford isotactic poly(racemic lactide)s, which were partially crystalline. Among the three examined catalysts, the tBu-substituted homosalen-Al catalyst on the Merrifield resin gave the most crystalline poly(racemic lactide), which showed a melting peak in the DSC measurement in the second run. Because of the immobilization of the catalyst on the resin, the obtained poly(racemic lactide) was colorless and never included the ligand-derived organic compounds in the polymer. The ligand resin was collected by filtration and was reusable.View full abstractDownload PDF (797K)
Note
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Kazuko FUJIWARA, Buenaventurada P. CALABIA, Fumi NINOMIYA, Masahiro FU ...2013 Volume 70 Issue 12 Pages 753-758
Published: December 25, 2013
Released on J-STAGE: December 25, 2013
JOURNAL FREE ACCESSBiomass based composites from poly-(lactic acid) (PLA) and empty fruit bunch fiber (EFB) were prepared. The mechanical and thermal properties of PLA/EFB composites samples were discussed. As a side effect, the biodegradation rate of PLA/EFB composites was increased by incorporation of EFB. Tensile strength was further improved by silane coupling treatment with 3-aminopropyltrimethoxysilane (APTM) of EFB. SEM observation showed interfacial adhesion between PLA and EFB was improved by this treatment.View full abstractDownload PDF (803K)
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