Formation of particles in the preparation of carboxylated polystyrene latexes

Carboxylated polystyrene latexes have been prepared by copolymerizing acrylic acid at the appropriate degree of neutralization in the absence or presence of sodium dodecyl sulfate (SDS), and the particle formation process was investigated from the number and uniformity of particles. In the absence of SDS or in a concentration range of SDS lower than 6.41 mmole/l., the formation of particles can predominantly be attributed to the precipitation of growing radicals formed in the aqueous phase; whereas in a concentration range of SDS higher than 6.41 mmole/l., the formation of particles can predominantly be attributed to the initiation of polymerization in the interior of SDS micelles containing solubilized styrene by the collision of growing radicals formed in the aqueous phase. In the former range, the number of particles increases linearly with increasing concentration of SDS below the critical concentration of 1.60 mmole/l., which is sufficient to stabilize particles formed by the precipitation of growing radicals, and remains constant above the critical concentration. The effect of initiator concentration as well as amount of styrene on the formation of particles also supports the particle formation process described above.     

The role of polyvinyl alcohol in emulsion polymerization

Emulsion polymerization of styrene (St) and vinyl acetate (VAc) in the presence of conventional polyvinyl alcohol (PVA), PVA modified with a terminal alkyl group or PVA modified with a terminal thiol group (HS-PVA) was compared. Whereas stable PVAc latexes were obtained, a stable PSt latex was obtained only in the case of HS-PVA. From the adsorption isotherms of these PVAs on the surface of PVAc and PSt latex particles, as well as the grafting efficiencies of VAc and St onto HS-PVA in relation to the stability of the polymerization process, the role of PVA in the emulsion polymerization was discussed.     

Gas transport in poly(vinyl-p-isopropylbenzoate): Comparison and correlation with some other poly(vinyl esters)

Gas permeability in poly(vinyl-p-isopropylbenzoate) (PVp-i-PrB) was determined by a timelag method. The transport properties were discussed from comparison with the permeability data of other poly(vinyl esters), which were studied previously. All these polymers are structurally related, and the size of a side group or the position of its substituent was changed systematically. The isopropyl group of PVp-i-PrB is attached at the para position of a phenyl ring and is the largest in size. As a result gas diffusivity and therefore permeability were increased. The effect of the substituent on gas diffusivity was explained as it increases the interchain and intrachain distances. The discussion was supported from the comparison of the density data between PVp-i-PrB and other poly(vinyl esters). The diffusion coefficients of six glassy poly(vinyl esters) were correlated at their T_g and good correlations were shown to the free volume and its fraction. On the other hand, gas solubility was little affected by the change of an alkyl group on a phenyl ring. The solubility data of PVp-i-PrB and poly(vinyl benzoate) were shown to be clearly correlated with the critical properties of the penetrants. © 1995 John Wiley & Sons, Inc.     

Fish Myosin Fragments Solubility and ANS-Fluorescence Intensity Affected by n-Butanol

Changes in the solubility and 8-anilino-1-napthalene sulfonate (ANS)-fluorescence intensity of oval filefish, tilapia, and black marlin myo-sins and their fragments by n-butanol were examined in connection with myosin gel-forming abilities. The thermal gel-forming abilities of myosins were greatly enhanced by the addition of 0.3–0.8M n-butanol. KC1 concentration-solubility curves revealed that after n-butanol addition a marked decrease in the solubility was observed for myosins and S-1s, whereas there was a slight decrease for rods. The fluorescence intensity of myosins-ANS in the presence of n-butanol increased markedly by heating at 30° and 35°C. A similar increase in the fluorescence intensity occurred in all S-ls-ANS, but not in rods.     

Recovery of residual nutrients from agri-food byproducts using a combination of solid-state fermentation and insect rearing

The present research develops an innovative nutrient recovery strategy for capturing of un-utilised nutrients from agri-food byproducts using a combination of solid state fermentation (SSF) and insect rearing. SSF of borage and flaxseed meals were performed using GRAS organisms to release indigenous nutrients and to produce additional nutrients. Proximate analysis of the SSF-meals showed increases in both lipid and protein contents. Black soldier fly larvae (BSFL) were then grown on these SSF-meals for 12 day. The meals fermented singularly with Lactobacillus plantarum or Aspergillus niger displayed up to 30% enhancement in BSFL biomass, and dual fermentation with L. plantarum and Aspergillus oryzae resulted in an additional 10% enhancement. These examinations showed SFL use over-90% of proteins and lipids in SSF-meals. The results indicate that fermentation of these low-value meals can boost the efficacy of larval growth and the recovery of nutrients from agricultural byproducts as larval biomass.     

Electrical and electroluminescent properties of poly(p-phenylene vinylene) LB films based LEDs using aluminum metal as the electrode

The electrical properties of poly(p-phenylene vinylene) (PPV) Langmuir-Blodgett (LB) films were investigated, wherein transparent indium-tin oxide (ITO) and aluminum (Al) were used as the electrodes. Their I–V characteristics depended strongly on the thickness of PPV LB film, and the electric conductivity of the PPV LB film was in the range of 10⁻²–10⁻¹⁵ (S/cm). Their C–V characteristics showed that the capacitance was reversibly proportional to the thickness of PPV LB film and was kept constant when the applied voltage changed from −1.0 V to +1.0 V. These results indicated that PPV LB film was an insulator in this range of applied voltage without doping. Under forward bias, yellow-green light emission was observed in PPV LB film based light emitting diodes (LEDs), the highest light emission reached more than 100 cd/m² in the case that PPV LB film was deposited for 80 layers, i.e. a ITO/PPV(80L)/Al device.     

Low-pressure CO2 sorption in poly(vinyl benzoate) conditioned to high-pressure CO2

Sorption of CO₂ in poly(vinyl benzoate) was gravimetrically measured at pressures up to 1 atm. Sorption isotherms were determined above and below the glass transition temperature T_g from 5 to 85°C. The isotherms were analyzed by the dual-mode sorption model assuming that the plasticizing effect of sorbed CO₂ is negligible at this pressure range. The solubilities and Henry's law dissolution parameters were compared with those obtained by the high-pressure sorption and permeation measurements. Henry's law dissolution parameters were in good agreement with one another. However, the solubilities first determined here were smaller than those determined by the high-pressure sorption experiment at the same temperature. It was clear that the Langmuir capacity of the present specimen was smaller in spite of similar high-pressure CO₂ exposure. Relaxation of the polymer was expected to be one of the reasons. This expectation was confirmed from the observation and analysis of sorption isotherms after two kinds of treatments. After annealing above T_g, the Langmuir capacity was shown to be decreased to 1/2 or even to 1/3 from the sorption isotherms below 45°C. This means that the conditioning to the high-pressure CO₂ surely has a large effect on the nature of glassy polymer. Just after high-pressure CO₂ exposure at 25°C, increased solubility was observed. Furthermore, the slow decrease of solubility, that is, the decrease of conditioning effect, was also followed from the continual measurements at 25°C. This result reflects not only the characteristic of sorption capacity after high-pressure CO₂ exposure, but also the relaxation of polymer in glassy state.     

Tunnelling through an embankment using all ground fasten method

The Tohoku Shinkansen Railway between Morioka and Hachinoe was opened on December 1, 2002. In this section, there are 20 tunnels. Second Itsukaichi tunnel is one of them, and it is a relatively short tunnel of 1175 m. At the Morioka portal, this tunnel crosses under National Highway No. 4 with a small depth of overburden 2–5 m where approximately 15,000 vehicles pass a day. The tunnel was excavated by NATM method. All Ground Fasten method was used as an auxiliary method. As a result, the face was prevented from collapsing and the tunnel was excavated while keeping the ground surface settlement to a minimum without interfering with road traffic.