Molecular aggregation of PEEK with PES blends and the block copolymers composed of PEEK and PES components

Polymer blends of PEEK with PES were prepared by the solution blending method. Copolymers composed of PEEK and PES components were synthesized from these oligomers. The formation conditions exerted an influence over the molecular aggregation and the crystallization behaviors of the blend films and block copolymers which were examined by X-ray diffractometry and DSC analysis. As a result, phase-separation in the blend films was found when the formation temperature was high. The blend films formed at 340°C, quenched and annealed at 180°C, exhibited the same crystallization behavior as those of PEEK. In the case of the blend films formed at 300°C, the annealing of the films at 250°C was required to crystallize the blend films. The T_g of a copolymer with a PEEK component content of more than 50% tends to shift toward a higher temperature than the T_g of PEEK itself, and the T_m of the copolymer toward a lower temperature than that of PEEK ist.     

Ethanol production from raw starch by a recombinant yeast having saccharification and fermentation activities

In order to develop a method for converting raw starch into ethanol efficiently, direct fermentation of ozonized raw starch using a recombinant yeast was investigated. Ozonolysis was carried out as a pretreatment to convert raw starch into ethanol rapidly and efficiently, and then the effect of the ozone degradation conditions on the degree of polymerization and the amount of amylose in a raw starch was determined. Since the degree of polymerization was low and the amount of amylose was high, raw starch treated with an ozone concentration of 40 gm^?3 and an ozonation time of 30 min was the material chosen for alcohol fermentation. Though the recombinant yeast could not convert the untreated raw starch, it converted the soluble starch and the ozonized raw starch at a comparatively high yield into ethanol. About 56% of the ozonized raw starch decomposed, and the ethanol concentration obtained from the ozonized raw starch was markedly greater than that obtained from untreated raw starch. The dynamic behavior of cell growth, substrate degradation, and ethanol production was examined in a continuous culture under various dilution rates, and the optimal dilution rate, ie 0.15 h^?1, was determined for maximizing the ethanol productivity (amount of ethanol produced per unit time). © 2002 Society of Chemical Industry     

Effects of bile acid feeding on hepatic deoxycholate 7α-hydroxylase activity in the hamster

In order to investigate the effects of bile acid feeding on hepatic microsomal deoxycholate 7α-hydroxylase activity, three different bile acids were administered (0.2% w/w in chow) to hamsters for two weeks. Deoxycholate 7α-hydroxylase activity was increased markedly by feeding of cholic acid (CA) and slightly by deoxycholic acid (DCA) Chenodeoxycholic acid (CDCA) had little effect on the enzyme activity. Feeding each of the bile acids significantly inhibited the activity of cholesterol 7α-hydroxylase in the order CDCA≥ DCA>CA. There was no correlation between deoxycholate 7α-hydroxylase activity and cholesterol 7α-hydroxylase activity. It is concluded that the activity of deoxycholate 7α-hydroxylase is up-regulated by feeding DCA and CA and that the mechanism seems to be different from that of cholesterol 7α-hydroxylase. The increased activity of hepatic deoxycholate 7α-hydroxylase by CA and DCA should be beneficial in minimizing the toxic effects of DCA in the hamster.     

Role of tungsten in promoting selective reduction of NO with CO over Ir/WO3–SiO2 catalysts

Catalytic hydrogenation of naphthalene to decalin was studied over a carbon-supported rhodium catalyst in supercritical carbon dioxide solvent at 333 K, and the results were compared with those in an organic solvent. cis-, trans-Decalin and tetralin were formed from the beginning of the reaction in supercritical carbon dioxide. Higher concentration of hydrogen in carbon dioxide solvent and on the active site, and also the suppression of desorption of partially hydrogenated tetralin molecules from the active site would be responsible for higher selectivity to cis-decalin in supercritical carbon dioxide than that in an organic solvent.     

Simple chemical syntheses of TAG monohydroperoxides

For the purpose of synthesizing standards to be used in the quantification of TAG hydroperoxides, three TAG (1,2-dioleoyl-3-palmitoylglycerol, 1-oleoyl-2-linoleoyl-3-palmitoylglycerol, and triolein) monohydroperoxides were chemically synthesized as authentic specimens. TAG were prepared by using a simple condensation in pyridine of glycerol and the corresponding acid chlorides. These TAG were then converted into monohydroperoxides by a photosensitized peroxidation. The synthesized monohydroperoxides were analyzed by normal-phase and RP-HPLC. The results of normal-phase HPLC analysis showed that monohydroperoxides from a corresponding TAG were a mixture of regioisomers. In RP-HPLC, however, the regioisomers of monohydroperoxides were not separated and gave a single peak, which may improve the sensitivity for the detection of TAG monohydroperoxides. In this study TAG monohydroperoxide standards were synthesized; these will be useful for the study of yet unknown biological and pathological roles of TAG hydroperoxides.     

Concentration of acetic acid in sulfite pulp evaporation drain by reverse osmosis

The evaporation drain of sulfite pulp spent liquor contains few volatile fatty acids, most of which is acetic acid. The main objective of this study is to recover acetic acid as the concentrated solution (about 4%), which could be used as a culture medium of the yeast. As acetic acid can easily pass through the cellulose acetate membrane, SP drains neutralized by NaOH, NH₄OH and Ca(OH)₂ were used as the feed solutions. In all cases, concentration by reverse osmosis was successfully carried out provided the appropriate pretreatment was employed. The recovery of acetic acid was 95.6, 90.5 and 98.2% for Na-, NH₄-, and Ca-drain, respectively. In addition, the recovered (permeated) water may be used as an industrial one.     

Prostaglandin-like substances formed during autoxidation of methyl linolenate

Prostaglandin-like substances other than 3-(2-ethyl-5-hydroxy-3-oxo)-cyclopentanyl-2-propenal (compound I), which upon reacting with amino acids form reddish pigments, were purified, and their chemical structures were determined. Three red pigment-forming substances (RPS) in autoxidized methyl linolenate were purified successively by gel chromatography on Sephadex LH-20, column chromatography and thin layer chromatography on Silica Gel 60, and by high performance liquid chromatography on μ-Porasil. IR spectra of the RPS showed the absorption of an ester group (νC=O 1730 cm⁻¹ in CHCl₃) and of a longer branched chain (νC-H 2800–3100 cm⁻¹), in addition to the absorption bands observed in compound I. Electron impact mass spectra of the trimethylsilyl ethers obtained after reduction with NaBH₄ and NaBD₄ were analyzed in detail and compared with those of compound I. The structures of the RPS were identified as stereoisomeric methyl 8-[2-(2-formylvinyl)-3-hydroxy-5-oxo-cyclopentanyl]-octanoates derived from methyl 12-hydroperoxy-linolenate. Presented at the general meeting of the Japanese Society of Scientific Fisheries, held at Tohoku University, Sendai, Japan, October 1984.     

Synthesis of tetramethyl-p-silphenylenesiloxanedimethylsiloxane triblock copolymer by employing living anionic polymerization

Dimethylsiloxane-tetramethyl-p-silphenylenesiloxane-dimethylsiloxane (DMS-TMPS-DMS) triblock copolymer was synthesized by employing living anionic polymerization of hexamethylcyclotrisiloxane (D₃). Two synthetic methods were carried out for the polymerization. One of those methods was the anionic polymerization of D₃ initiated at the silanolate anion which was prepared from the terminal hydroxyl group of silanol-terminated TMPS prepolymer by reaction with n-butyllithium (method 1). The other was the coupling reaction of vinyl-terminated TMPS prepolymer with hydrosilyl-terminated DMS prepolymer obtained from the anionic polymerization of D₃ by using diphenylmethylsilanolate anion as initiator (method 2). In method 1, DMS contents of the copolymers ranged from 25.8 to 72.5 wt% and the values agreed with the ratio of D₃ to TMPS prepolymer. The weight-average molecular weights ranged from 1.36×10⁴ to 19.4×10⁴ and were close to the predicted values calculated from the $\text{M}\text{?}{}_{\mathrm{v}}$ of the TMPS prepolymer and the amount of D₃ added. In the case of method 2, weight-average molecular weights ranged from 19.5×10⁴ to 24.2×10⁴. The high molecular weight copolymer could thus be obtained by method 2. Intrinsic viscosity values of the triblock copolymers agreed with calculated values obtained by considering the copolymer as a binary mixture of these homopolymers. Differential scanning calorimetry and thermogravimetry were carried out on the triblock copolymers. The equilibrium melting temperatures of each of the copolymers were very close to that of poly-TMPS (160°C). The glass transition temperature and heat of fusion were decreased as the DMS content was increased. The thermogravimetric curves for the copolymers indicated that the thermal stability of the triblock copolymer was intermediate between the DMS and TMPS homopolymers.     

Separation of surfactant mixtures and their homologs by high performance liquid chromatography

A technique for separating similar and diverse ionogenic mixtures into their individual homologs was studied by high performance liquid chromatography on an octadecyl-silica (TSK Gel LS-410) column. Conditions used for the separation were: column size, 6 mm id×200 mm; mobile phase, water/methanol (15:85, v/v) containing (a) 1.0 M sodium perchlorate and adjsting to pH 2.5 with phosphoric acid, (b) 0.1 M and pH 3.5; column temp., 50 C. By using 2 mobile phase conditions, various surfactant mixtures were separated into their individual homologs and simultaneously distinguished from each other, regardless of their ionogenic properties.     

Differential scanning calorimetric studies on the glass transition temperature of polyhydroxystyrene derivatives containing sorbed water

Poly(4-acetoxystyrene) (PAS) and poly(4-acetoxy-3-methoxystyrene) (PAMS), poly(4-hydroxystyrene) (PHS) and poly(4-hydroxy-3-methoxystyrene) (PHMS) have been prepared. The effects of hydrogen bonding on the glass transition temperatures (T_g) of these polymers have been studied by differential scanning calorimetry. The T_g′s of partially hydrolyzed PAS and PAMS increased with the degree of hydrolysis. Partially hydrolyzed PAS and PAMS are estimated to be random copolymers, judging from the correspondence between the calculated and observed T_g′s of these polymers. The effect of water on the glass transition was also studied, and it was clarified how water adsorbed on the polymers acts as a hydrogen-bond breaker. The ‘critical water content’ is calculated from the decrease of T_g by water absorption, and the relation between hydrogen bonding and T_g is discussed.