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Acrylonitrilestyrene copolymer/clay nanocomposite (AS-clay) was prepared by copolymerization of acrylonitrile and styrene in the presence of monmorillonaite-type clay that had been modified with 4-vinylpyridine and benzalkonium chloride. The spacing of the intercalation in the nanocomposites was investigated by X-ray diffraction and FT-IR. Izod impact and burning rate of ABS resin mixed with AS- clay were examined. The ABS/clay nanocomposite had low Izod impact strength and high burning resistance, as compared with the valves for ABS resin. [ABSTRACT FROM AUTHOR]

Membrane resistance and permselectivity for counter-ions have important roles in determining the performance of cation-exchange membranes (CEMs). In this study, PVA-based polyanions—poly(vinyl alcohol-b-sodium styrene sulfonate)—were synthesized, changing the molar percentages CCEG of the cation-exchange groups with respect to the vinyl alcohol groups. From the block copolymer, poly(vinyl alcohol) (PVA)-based CEMs, hereafter called "B-CEMs", were prepared by crosslinking the PVA chains with glutaraldehyde (GA) solution at various GA concentrations CGA. The ionic transport properties of the B-CEMs were compared with those previously reported for the CEMs prepared using a random copolymer—poly(vinyl alcohol-co-2-acrylamido-2-methylpropane sulfonic acid)—hereafter called "R-CEMs". The B-CEMs had lower water content than the R-CEMs at equal molar percentages of the cation-exchange groups. The charge density of the B-CEMs increased as CCEG increased, and reached a maximum value, which increased with increasing CGA. A maximum charge density of 1.47 mol/dm3 was obtained for a B-CEM with CCEG = 2.9 mol% and CGA = 0.10 vol.%, indicating that the B-CEM had almost two-thirds of the permselectivity of a commercial CEM (CMX: ASTOM Corp. Japan). The dynamic transport number and membrane resistance of a B-CEM with CCEG = 8.3 mol% and CGA = 0.10 vol.% were 0.99 and 1.6 Ωcm2, respectively. The B-CEM showed higher dynamic transport numbers than those of the R-CEMs with similar membrane resistances. [ABSTRACT FROM AUTHOR]

Objectives: To survey the loss of colour vision among Japanese workers who have been exposed to styrene concentrations currently considered low (about 20 ppm). Also to assess the effects of styrene by examination of the nature of the relation between disorder of colour vision and age, alcohol consumption, and other variables.Methods: Colour discrimination was examined in 64 male workers exposed to styrene (mean age; 38.0, mean exposed years; 7.0) and in 69 controls (mean age; 38.0). A standardised questionnaire was adopted to collect work history, occupational or non-occupational solvent exposure, alcohol consumption, and drug use. Colour vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the colour confusion index (CCI).Results: The mean atmospheric styrene concentration was about 20 ppm. The mean urinary concentration of mandelic acid was 0.22 g/l. There was a significant difference in CCI between exposed workers and age matched controls. Colour vision of workers whose concentration of urinary mandelic acid was > or = 0.42 g/l was significantly impaired when compared with workers whose concentration was < 0.42 g/l. Multiple linear regression analysis that controlled confounding variables such as age, alcohol consumption, smoking, and educational attainment showed that the CCI was significantly related to the concentration of urinary mandelic acid. In both exposed workers and controls, the types of defects were mostly blue-yellow loss, although a few subjects showed complex loss. No one showed only red-green loss.Conclusions: These findings suggest that exposure to moderate styrene concentrations can lead to impairment of colour vision, and that there is a significant correlation with the urinary metabolite of styrene. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present survey is to identify organic solvents commonly used in various workplaces in Japan., Methods: A total of 24 occupational health service institutions (OHSI) distributed nationwide in Japan offered data on types of solvent workplaces, types of solvents used therein, and the solvent concentrations surveyed in a 2-month period between April and May 1996 to form a data base (OHSI data base, consisting of 1597 cases). Separately, Kyoto Industrial Health Association (KIHA) offered information on 948 cases studied during a 1-year period ranging from April 1995 to March 1996 (KIHA data base). The two data bases were treated in parallel to examine the reproducibility of the results., Results: Detection prevalence was very low (0-1%) for almost half of the 47 legally regulated solvents. Among the solvents in use, toluene was most frequently detected, although the prevalence appeared to be reduced as compared with that recorded for the early 1980s. The most frequently observed solvent combinations comprised toluene, xylenes, and ethyl acetate in the OHSI data base and toluene, xylenes, and methanol in the KIHA data base. Contrary to the case in the 1980s, dichloromethane was used more often than trichloroethylene as a degreasing agent in the present survey. No use was detected for carbon tetrachloride, chloroform, 1,2-dichloroethane, 1,2-dichloroethylene, or 1,1,2,2-tetrachloroethane except for research purposes., Conclusions: Toluene remained the most common solvent and was used in combination with xylenes, ethyl acetate, and methanol. There was an increase in the use of dichloromethane as a degreasing agent.