| 1. |
- Lastbom, L, et al.
(författare)
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Effects of thermal degradation products from polyurethane foams based on toluene diisocyanate and diphenylmethane diisocyanate on isolated, perfused lung of guinea pig
- 2003
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 29:2, s. 152-158
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The composition of thermal degradation products from two types of polyurethane foams, one based on toluene diisocyanate (TDI) and the other on diphenylmethane diisocyanate (MDI), was analyzed and their toxic lung effects were compared. Methods Isolated perfused lungs of guinea pig were subjected to thermal decomposition products of polyurethane foams from an aerosol generator with compartments for diluting, mixing, and sampling. Results Thermal degradation of MDI-based polyurethane foams released MDI, phenyl isocyanate, and methyl isocyanate. The emitted particulate fraction was 75% for MDI, whereas that for TDI from TDI-based polyurethane foam was 3%. Thermal degradation products from MDI-based foam caused a pronounced dose-dependent decrease in the measured lung function parameters (conductance and compliance). In contrast, the thermal degradation products from TDI-based foam did not cause any decrease in lung function. Conclusions Thermal degradation products generated from MDI-based polyurethane foam were more toxic to the lung than those generated from TDI-based polyurethane foam. This difference was probable due to MDI in the particle phase.
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| 2. |
- Nordqvist, Y, et al.
(författare)
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A chemosorptive cylindrical denuder designed for personal exposure measurements of isocyanates-evaluation on generated aerosols of 4,4 '-methylenediphenyl diisocyanate
- 2005
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry (RSC). - 1464-0325 .- 1464-0333. ; 7:5, s. 469-474
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Tidskriftsartikel (refereegranskat)abstract
- A denuder/filter system constructed for solvent-free personal exposure measurements was evaluated for separation of vapour and particulate 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) generated from heated PUR-foam. The two different phases were collected in the denuder and on the filter, respectively, by chemosorption on a polydimethylsiloxane (SE-30)-dibutylamine (DBA) stationary phase. Both repeatability and the total mass concentration of 4,4'-MDI were similar to that obtained from the reference method, in this case an impinger/filter system. The penetration of particles through the denuder at 300 ml min(-1) was nearly 100% in the particle size range 25 to 700 nm, which fits well with the Gormley-Kennedy equation. Denuder/filter sampling of the 4,4'-MDI aerosol at 500 ml min(-1) yielded a phase distribution that was in accordance with the results from the reference method. The method limit of detection was 6 ng m(-3) and 4 ng m(-3) for the denuder and filter, respectively, when using an air sampling flow rate of 300 ml min(-1) and a sampling period of 15 min. This is well below the Swedish occupational exposure limit (OEL) of 50 and 100 μ g m(-3) for an 8-hour working day and a 5-min period, respectively.
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| 3. |
- Sjoholm, E, et al.
(författare)
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Aggregation of cellulose in lithium chloride/N,N-dimethylacetamide
- 2000
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Ingår i: CARBOHYDRATE POLYMERS. - : ELSEVIER SCI LTD. - 0144-8617. ; 41:2, s. 153-161
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Hardwood kraft pulps can be completely dissolved in lithium chloride/N,N-dimethylacetamide (LiCl/DMAc). The cellulose and hemicellulose components can be separated by size exclusion chromatography (SEC). The molecular weight distribution that corresponds
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