Cage Nanofillers' Influence on Fire Hazard and Toxic Gases Emitted during Thermal Decomposition of Polyurethane Foam.

Polyurethane (PUR), as an engineering polymer, is widely used in many sectors of industries. However, the high fire risks associated with PUR, including the smoke density, a high heat release rate, and the toxicity of combustion products limit its applications in many fields. This paper presents the influence of silsesquioxane fillers, alone and in a synergistic system with halogen-free flame-retardant compounds, on reducing the fire hazard of polyurethane foams. The flammability of PUR composites was determined with the use of a pyrolysis combustion flow calorimeter (PCFC) and a cone calorimeter. The flammability results were supplemented with smoke emission values obtained with the use of a smoke density chamber (SDC) and toxicometric indexes. Toxicometric indexes were determined with the use of an innovative method consisting of a thermo-balance connected to a gas analyzer with the use of a heated transfer line. The obtained test results clearly indicate that the used silsesquioxane compounds, especially in combination with organic phosphorus compounds, reduced the fire risk, as expressed by parameters such as the maximum heat release rate (HRRmax), the total heat release rate (THR), and the maximum smoke density (SDmax). The flame-retardant non-halogen system also reduced the amounts of toxic gases emitted during the decomposition of PUR, especially NOx, HCN, NH3, CO and CO2. According to the literature review, complex studies on the fire hazard of a system of POSS-phosphorus compounds in the PUR matrix have not been published yet. This article presents the complex results of studies, indicating that the POSS-phosphorous compound system can be treated as an alternative to toxic halogen flame-retardant compounds in order to decrease the fire hazard of PUR foam.

Effect of Hybrid Filler, Carbon Black-Lignocellulose, on Fire Hazard Reduction, including PAHs and PCDDs/Fs of Natural Rubber Composites.

The smoke emitted during thermal decomposition of elastomeric composites contains a significant number of carcinogenic and mutagenic compounds from the group of polycyclic aromatic hydrocarbons, PAHs, as well as polychlorinated dibenzo-p-dioxins and furans, PCDDs/Fs. By replacing carbon black with a specific amount of lignocellulose filler, we noticeably reduced the fire hazard caused by elastomeric composites. The lignocellulose filler reduced the parameters associated with the flammability of the tested composites, decreased the smoke emission, and limited the toxicity of gaseous decomposition products expressed as a toximetric indicator and the sum of PAHs and PCDDs/Fs. The natural filler also reduced emission of gases that constitute the basis for determination of the value of the toximetric indicator WLC50SM. The flammability and optical density of the smoke were determined in accordance with the applicable European standards, with the use of a cone calorimeter and a chamber for smoke optical density tests. PCDD/F and PAH were determined using the GCMS-MS technique. The toximetric indicator was determined using the FB-FTIR method (fluidised bed reactor and the infrared spectrum analysis).

Zooremediation of leachates from municipal waste using Eisenia fetida (SAV.).

Leachates from municipal landfills are formed as infiltration waters flowing through the landfill. They contain toxic, dissolved products of biochemical reactions taking place in the deposit. They cause soil and groundwater pollution. It is necessary to take them out of the landfill cover and utilize toxins contained therein, in particular heavy metals. Such processes are conducted with the use of microorganisms. Due to the content of toxic compounds, introducing leachates into the process of biological purification poses a threat to the microorganisms used in these processes. An alternative to microbial co-treatment of sludge and leachate as well as soil contaminated with communal leachate is to use red hybrid of California (Eisenia fetida Sav.), an earthworm resistant to environmental toxins, in particular heavy metals. The aim of the conducted research is to demonstrate the possibility of using red hybrid of California in leachate bioutilization as a complementary or alternative method to the process of leachate utilization with the use of microorganisms. The obtained results led to the conclusion that Eisenia fetida accumulates environmental toxins well. By collecting and processing them in the tissues, it remedies the substrate and retains long life and fertility, and the ability to reproduce. The research demonstrated high dynamics of population growth (from 25 individuals in the initial deposit to 298 individuals after six months of research). These properties are related to the presence of enzyme proteins from the metallothionein group in the gastrointestinal tract cells. Packing heavy metals found in leachates into the metallothionein coat limits their toxic effect on earthworm tissues, which confirms the possibility of using earthworms in the processes of detoxification of municipal leachate.