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- Ekelund, Maria, et al.
(författare)
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Evaporative loss kinetics of di(2-ethylhexyl)phthalate (DEHP) from pristine DEHP and plasticized PVC
- 2010
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Ingår i: Polymer degradation and stability. - : Elsevier BV. - 0141-3910 .- 1873-2321. ; 95:9, s. 1789-1793
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Tidskriftsartikel (refereegranskat)abstract
- The migration of di(2-ethylhexyl)phthalate (DEHP) from poly(vinyl chloride) (PVC) to a surrounding gas phase at temperatures below 120 degrees C kinetically is controlled by evaporation. The effects on the DEHP loss rate of nitrogen flow rate, relative humidity and degradation of the plasticizer at 100 degrees C was assessed. The sample mass decreased linearly with time for both pristine DEHP and plasticized PVC at comparable rates, suggesting that a thin film of DEHP was present on the jacketing insulation during desorption. The latter hypothesis was supported by infrared spectroscopy and by the fact that DEHP is an amphiphilic molecule that will tend to aggregate at the surface with the hydrophobic 2-ethylhexyl units at the air interface. The effect on the migration rate of moisture present in the gas phase was negligible. The DEHP loss rate increased in a retarding non-linear fashion with increasing gas flow rate. In one of the experiments, DEHP was accidently degraded as revealed by discoloration, the presence of low molar mass degradation products (liquid chromatography) containing additional carbonyl groups (infrared spectroscopy) and an increase in the evaporation rate at temperatures between 100 and 130 degrees C. (C) 2010 Elsevier Ltd. All rights reserved.
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| 2. |
- Jäverberg, Nadejda, 1977-, et al.
(författare)
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Dielectric properties of alumina-filled poly(ethylene-co-butyl acrylate) nanocomposites
- 2010
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Ingår i: 2010 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (CEIDP). - : IEEE. - 9781424494705 ; , s. 5724031-
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Konferensbidrag (refereegranskat)abstract
- The dielectric properties of poly (ethylene-co-butyl acrylate) with 13 wt% of butyl acrylate (EBA) filled with alumina nanoparticles (diameter < 50 nm) were studied as a function of particle coating and filler content (2, 6 and 12 wt%). The particles were either unmodified or surface treated either with aminopropyl triethoxysilane or octyltriethoxysilane. The complex permittivity was measured with an IDA200 dielectric spectroscopy analyzer at applied voltage of 200 Vpeak with frequencies varying between 1 mHz and up to 1 kHz at different temperatures (25, 45 and 65°C). Measurements are performed in dry conditions. Pure EBA shows two regions of frequency dispersion in the complex permittivity: a broad relaxation peak in the order of MHz and a characteristic low frequency dispersion that likely is a Maxwell-Wagner response due to a barrier blocking conduction process. Obtained data fits well to a sum of two Havriliak-Negami expressions. Adding nanoparticles to the EBA matrix changes the low frequency dispersion behaviour significantly. Differences in dielectric losses between nanocomposites with different surface treatment seem to be small. The differences in dielectric constant, however, are more pronounced and seem to indicate better dispersion with octylthriethoxysilane surface treatment.
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