Thermal Insulating Rigid Polyurethane Foams with Bio-Polyol from Rapeseed Oil Modified by Phosphorus Additive and Reactive Flame Retardants.

In this article, rigid polyurethane foams obtained with the addition of a bio-polyol from rapeseed oil, were modified with the dimethyl propane phosphonate as additive flame retardant and two reactive flame retardants diethyl (hydroxymethyl)phosphonate and diethyl bis-(2-hydroxyethyl)-aminomethylphosphonate. The influence of used flame retardants on the foaming process and characteristic processing times of tested polyurethane systems were determined. The obtained foams were tested in terms of cell structure, physical and mechanical properties, as well as flammability. Modified foams had worse mechanical and thermal insulation properties, caused by lower cellular density and higher anisotropy coefficient in the cross-section parallel to the foam rise direction, compared to unmodified foam. However, the thermal conductivity of all tested foam materials was lower than 25.82 mW/m∙K. The applied modifiers effectively reduced the flammability of rigid polyurethane foams, among others, increasing the oxygen index above 21.4 vol.%, reducing the total heat released by about 41-51% and the rate of heat release by about 2-52%. A correlation between the limiting oxygen index values and both total heat released parameters from the pyrolysis combustion flow calorimetry and cone calorimetry was observed. The correlation was also visible between the value of the heat release capacity (HRC) parameter obtained from the pyrolysis combustion flow calorimetry and the maximum average rate of heat emission (MARHE) from the cone calorimeter test.

Deep-sea bacteria enriched by oil and dispersant from the Deepwater Horizon spill.

The Deepwater Horizon oil spill resulted in a massive influx of hydrocarbons into the Gulf of Mexico (the Gulf). To better understand the fate of the oil, we enriched and isolated indigenous hydrocarbon-degrading bacteria from deep, uncontaminated waters from the Gulf with oil (Macondo MC252) and dispersant used during the spill (COREXIT 9500). During 20 days of incubation at 5°C, CO(2) evolution, hydrocarbon concentrations and the microbial community composition were determined. Approximately 60% to 25% of the dissolved oil with or without COREXIT, respectively, was degraded, in addition to some hydrocarbons in the COREXIT. FeCl(2) addition initially increased respiration rates, but not the total amount of hydrocarbons degraded. 16S rRNA gene sequencing revealed a succession in the microbial community over time, with an increase in abundance of Colwellia and Oceanospirillales during the incubations. Flocs formed during incubations with oil and/or COREXIT in the absence of FeCl(2) . Synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy revealed that the flocs were comprised of oil, carbohydrates and biomass. Colwellia were the dominant bacteria in the flocs. Colwellia sp. strain RC25 was isolated from one of the enrichments and confirmed to rapidly degrade high amounts (approximately 75%) of the MC252 oil at 5°C. Together these data highlight several features that provide Colwellia with the capacity to degrade oil in cold, deep marine habitats, including aggregation together with oil droplets into flocs and hydrocarbon degradation ability.

Deep-sea oil plume enriches indigenous oil-degrading bacteria.

The biological effects and expected fate of the vast amount of oil in the Gulf of Mexico from the Deepwater Horizon blowout are unknown owing to the depth and magnitude of this event. Here, we report that the dispersed hydrocarbon plume stimulated deep-sea indigenous γ-Proteobacteria that are closely related to known petroleum degraders. Hydrocarbon-degrading genes coincided with the concentration of various oil contaminants. Changes in hydrocarbon composition with distance from the source and incubation experiments with environmental isolates demonstrated faster-than-expected hydrocarbon biodegradation rates at 5°C. Based on these results, the potential exists for intrinsic bioremediation of the oil plume in the deep-water column without substantial oxygen drawdown.