Literatura científica selecionada sobre o tema "Fireproofing agent"

The electrical conductivity of thermoplastic elastomers (TPEs) modified with gaseous chlorine was studied. A TPE based on polyether (‘Vitur’-grade polyurethane) and the same TPE but with phosphorus-containing fireproofing agent were held in gaseous fluorine for 1 and 3 h, and were also treated with alcohol after fluorination. The surface morphology of specimens was studied using an atomic force microscope (AFM). The changes in morphology were similar to the changes observed after the surface fluorination of rubbers. The volume and surface resistivities were measured using an Agilent 4339B instrument (USA). In all cases, the volume resistivities of modified TPEs were two orders of magnitude lower than those of the initial TPEs. The introduction of a fireproofing agent leads to a 2.5-fold reduction in volume resistivity, and a 100-fold reduction in surface reactivity. The influence of the fireproofing agent is associated with it having an effect similar to that of fillers, and with the formation of a thin layer on the surface of specimens. it was shown that ethanol treatment leads to a reduction in volume resistivity.

The influence of the types of polyolefin elastomer (TPE-O) on the processing, physicomechanical, and service properties of composites with a high filler (fireproofing agent) content was investigated. These composites are used to produce products by extrusion.

Introduction. The analysis of flame retardants and extinguishing agents used for preventing and extinguishing fires in an ecosystem is carried out. It is shown that at present there are no weatherproof, environmentally friendly and cost effective extinguishing agents capable of stopping wood and peat burning. Purpose and objectives. Development of cost effective and environmentally friendly synthetic agents capable of both flame retarding and extinguishing natural combustible materials. Materials and methods. Synthetic dispersions of ammonium phosphates of two- and three-valence metals, as well as wood and peat fireproofed by them are the object of the study. Physical and chemical properties of synthesis products in comparison with their fire retarding efficiency are examined. Fireproofing, fire extinguishing, as well as physical and chemical properties of synthesized products are determined using GOST-regulated methods of thermal and chemical analysis, scanning electron microscopy and original methods. Results and discussion. The formulation of Kompleksil synthetic compound effective in extinguishing and fireproofing wood and peat is optimized using a full factorial experiment. At the same time, the inflow of volatile nitrogen containing products into the gaseous phase is identified as the dominating burning inhibition process common for natural combustible materials. The weather resistance (preservation of fireproof properties in respect of forest combustible materials at 79 mm precipitation), forest and environment enhancement (improvement of mineral nutrition conditions and growth of forest plant communities) properties of Kompleksil compound are identified. Conclusions. A cost effective synthetic compound based on natural mineral materials showing fireproofing and extinguishing efficiency when protecting forest combustible materials and peat is developed. This compound was tested in the process of extinguishing real wildfires; its weather resistance is identified, and the positive response of forest plant communities to the application of this multiple action compound is registered. The use of Kompleksil allows to reduce time expenditures and fire extinguishing agent consumption when extinguishing wildfires, which significantly reduces material damage.

The effect of a modifying additive – a polybutylenetetramethylene oxide (PBT-PTMO) block copolymer of grade V-1000 – on the processability and mechanical properties of polybutylene terephthalate (PBT) was investigated. It was shown that the mixing of the thermoplastic elastomer – the block copolymer of grade V-1000 – with the rigid, hard, but relatively brittle structural material PBT makes it possible to produce materials with a high level of properties. The modification of PBT with the block copolymer leads to an increase in its impact strength without any perceptible loss in tensile strength. Furthermore, the addition of a small amount of block copolymer to PBT improves its processability. The developed PBT composite with the optimum content of modifying additive and fireproofing agent is recommended for the manufacture of moulded articles of decorative-structural designation, and also for the partial replacement of polyamides PA-12L and PA-610L.

Certain questions concerning the development of new polymer fireproofing agents for cellulose materials are considered. The mechanisms of the fireproofing characteristics of the new polymers are clarified.

The impact of fire retardant waste on the aquatic environment was investigated at Abbotsford Airport located in the Lower Fraser Valley, in Southwestern British Columbia. The cleaning of fire fighting aircraft results in significant quantities of fire retardant waste being washed into the airport drainage system with subsequent transport to a drainage ditch located in the southwest corner of the Airport Chemical components of the fire retardant likely to be of environmental concern were identified as ammonia, phosphate, and a corrosion inhibitor. Glacial and outwash deposits consisting of sands and gravels comprise the surficial geology of the study area. Hence, the fire retardant waste would have the potential to impact both surface water and groundwater resources. Therefore there was concern due to the extensive use of groundwater in the local area for both drinking and irrigational purposes. The major components of the research design were 1) assessment of the spatial and temporal distribution of fire retardant introduced into the aquatic environment, and 2) overall impact of fire retardant contamination on surface water and groundwater quality. A long term and two short term monitoring programs were designed to determine the rate of transport and distribution of the fire retardant in the aquatic environment Results showed that although the fire retardant was observed to wash through the drainage system into the stream, no measurable impact on surface water quality was recorded during the study period. Fire retardant components which would cause surface water contamination are ammonia, phosphorus, iron and chromium. A significant rise in nitrate-nitrogen concentration was detected in groundwater samples less than a day after fire retardant waste was recorded in measurable quantities in the ditch water. Temporal distribution of fire retardant in the aquatic environment was correlated with the high hydraulic conductivity of the subsurface and specific hydrological events involving heavy precipitation. Results from the laboratory column experiments indicated that components of the Fire retardant were not retained in the soil and would therefore be rapidly leached into groundwater. Surface water quality and groundwater quality results were compared with established water quality standards for drinking water and protection of freshwater aquatic life. On the basis of these standards the fire retardant waste was not found to contribute to degradation of the surface and groundwaters at Abbotsford Airport Overall impact of the fire retardant waste on the aquatic environment at Abbotsford Airport during the study period was not found to be significant The low fire season combined with a change in washing policy resulted in a fewer number of planes being cleaned at Abbotsford Airport during 1983-84. Therefore, the impact on the aquatic environment recorded during this period cannot be considered typical.
Graduate and Postdoctoral Studies
Graduate

Los retardantes de llama halogenados (HFRs) se aplican a una gran variedad de materiales, como muebles, textiles, material electrónico, etc., con el objetivo de prevenir los incendios. La demanda global se incrementa año tras año, con el agravante de que son liberados al medio ambiente desde los productos que los contienen. Algunos de ellos han sido prohibidos en los últimos años, pero otros HFRs alternativos han aparecido como posibles substitutos. Es el caso de los norbornenos halogenados (HNs), de los cuales se dispone poca información pese a haber sido usados desde hace años. En esta tesis se pretendió evaluar el impacto que estos compuestos causan en el medio ambiente. Para ello, primero se desarrollaron metodologías adecuadas para el análisis de los mismos en diferentes matrices ambientales y biológicas. Estas metodologías se basaron en el uso de la GC-MS-MS, técnica que permitió obtener sensibilidades y selectividades adecuadas para el análisis de estos compuestos en sedimento, lodos, peces, huevos y grasa de delfín. Las metodologías desarrolladas se aplicaron en muestras de sedimento procedentes de Chile, Colombia y España, detectando PBDEs en las 3 zonas, como era de esperar dada su conocida ubicuidad. En cambio, fue la primera vez que se detectaron los HNs en sedimentos de Europa. Del mismo modo los HNs se identificaron en lodos de 7 depuradoras españolas, siendo la primera vez que se determinaba el Dec 603 en esta matriz. Se vio como el DP domina el perfil de contaminación en lodos y sedimentos, así como que el DBDPE y el BDE-209 mostraban concentraciones similares en ambas matrices, indicando que el DBDPE podría estar siendo usado como substituto. El siguiente paso fue el análisis de muestras de 30 especies, pertenecientes a diferentes cadenas tróficas acuáticas (Chile y Mediterráneo Sur-Oeste) y terrestres (Parque Natural de Doñana), siendo PBDEs, HBCD, BFRs emergentes, HNs y HNPs detectados en prácticamente todas las especies. Se observaron diferencias geográficas entre los niveles de contaminación encontrados en las distintas zonas. Además, se detectaron HNs en zonas alejadas de los focos de producción (EE.UU y China), tanto en matrices ambientales como en especies con dietas muy diferentes. DP fue el HN más abundante en la biota de Chile, mientras que el Dec 602 lo fue tanto en delfines como en aves de España. La capacidad de bioacumulación y biomagnificación de los HNs se evaluó y comparó con la de los PBDEs. El Dec 602 mostró BSAF y capacidad de biomagnificación (evaluada mediante correlación con el 615N) comparable a la del BDE-47, mientras que el DP mostró un comportamiento similar al BDE-209. Así pues, parece que se debería prestar más atención a los HNs, especialmente al Dec 602 y al DP, vistos sus niveles en biota. El estudio de muestras de grasa y cerebro de distintos delfines permitió evaluar una posible acumulación específica en cerebro, hecho que se identificó para el BDE-153, HBB y TetraBHD. De todos modos, todos los HNs mostraron la capacidad de atravesar la BBB y acumularse en el cerebro. Por ello, siempre que exista la posibilidad convendría estudiar otros tejidos además de la grasa, único tejido estudiado habitualmente en delfines. Por otro lado, se tuvo la oportunidad de llevar a cabo un estudio de tendencias temporales a partir del análisis de huevos de aves recogidos entre 1999 y 2012, observando una disminución de los niveles de los PBDEs pero no de los HNs. Por último, se evaluaron los efectos toxicológicos de algunos HFRs mediante exposiciones in vivo. Los resultados mostraron como el DP presentaba una mayor capacidad genotóxica que el BDE-209, induciendo daños a concentraciones menores. No se observaron efectos significativos a nivel fisiológico.
Halogenated flame retardants (HFRs) are present in a wide range of materials, such as furniture, textiles, electronic equipment, and so on. They are continuously entering the environment since its demand is increasing every year. Even if some HFRs have been banned, other alternative FRs appeared as replacements. Information regarding the occurrence, behavior and effects of alternative HFRs such as dechlorane plus and related compounds is still scarce even though they have been used for many years. Firstly, two sensitive and selective methodologies by GC-MS-MS were developed for the analysis of HFRs in several environmental and biological matrices. Sediments from different areas were analyzed, representing the first report of HNs in European sediments. Moreover, sludge from various wastewater treatment plants from Spain was also analyzed, representing the first report of Dec 603 in sludge worldwide and showing that DP dominates the HN profile in sludge. Furthermore, DBDPE and BDE-209 concentrations were in the same order, as observed also in sediments. After determining its presence in environmental matrices next logical step was the analysis of species corresponding to different trophic chains. A total of 30 different species from aquatic and terrestrial ecosystems were studied and target compounds were detected in almost all of them, showing their worldwide presence and bioaccumulation capacity. Concentrations showed a geographical dependent behavior, and in addition HNs were detected in areas far away from production sources. Bioaccumulation and biomagnification capacities were also evaluated. Dec 602 showed similar behavior than BDE-47, while Dec 603 and DP were closer to BDE-209. Overall, it seems that more attention should be paid to HNs due to their presence in a wide range of species, and to Dec 602 in particular considering its high concentrations in biota. Furthermore, tissue specific accumulation (blubber-brain) was observed for some compounds. As regards time trends, decrease in PBDE concentrations in birds, especially the components included in the Penta-BDE mixture, was observed. On the contrary, HNs concentrations did not change during the decade studied. Finally, toxicological effects of Deca-BDE and DP commercial mixtures were evaluated. DP caused similar or even higher damage than BDE-209 at lower concentrations.

Aquesta Tesi Doctoral presenta l’estudi de degradació de dues classes de retardants de flama bromats (els difenilèters polibromats (PBDEs) i els bromofenols) mitjançant tècniques espectroscòpiques, cromatogràfiques i quimiomètriques. S’ha estudiat dos tipus de degradació: la fotodegradaciói la biodegradació. A més dels estudis específics d’aquests processos, s’ha treballat en la revisió de metodologia existent i en el desenvolupament de nous procediments per a la interpretació d’informació procedent de dades ambientals relacionades amb la presència i destí de contaminants bromats. ESTUDIS DE FOTODEGRADACIÓ Pel que fa als estudis de fotodegradació, s’ha proporcionat una metodologia de seguiment experimental (cromatogràfic i espectroscòpic), tractament quimiomètric i interpretació de resultats vàlida per a la investigació de qualsevol procés de fotodegradació. Per al tractament de les dades s’ha suggerit el mètode de resolució multivariant de corbes per mínims quadrats alternats amb modelització flexible (MCR-ALS) i amb modelització híbrida (HS-MCR), que permeten l’estimació dels perfils de concentració i dels espectres purs dels diferents productes de degradació, així com de les constants de velocitat associades al procés. S’ha comprovat també que l’ús de nous acoblaments cromatogràfics (HPLC-DAD-MS) i cromatogràfic/espectroscòpic són una eina poderosa per a l'estudi general de processos de fotodegradació. Aquests acoblaments han permès obtenir una descripció completa de la cinètica dels processos de fotodegradació amb tots els passos successius, constants cinètiques i fotoproductes formats. A partir de la metodologia proposada s’ha pogut presentar una descripció del procés de fotodegradació del DecaBDE i de sis bromofenols, així com avaluar l’efecte de diversos factors (polaritat en el solvent, grau de bromació, font de radiació...) en la cinètica i en la natura dels productes formats en aquests processos. Pel que fa al procés de fotodegradació del DecaBDE, s’ha observat que és un sistema complex en el qual hi ha involucrats un gran nombre de productes. S’ha postulat que el DecaBDE es pot transformar en compostos més tòxics, com congèneres amb un nombre menor de broms i dibenzofurans. Per tant s’adverteix de l’impacte ambiental i de l’amenaça per la salut pública de l’ús d’aquest compost. S’ha observat, a més, que en augmentar la polaritat del solvent disminueix la velocitat de fotodegradació del DecaBDE. Pel que fa als processos de fotodegradació dels sis bromofenols de diferent grau de bromació, s’ha observat que són també sistemes molt complexos i donen lloc un nombre elevat de fotoproductes. S’ha suggerit que aquests processos presenten mecanismes de reaccions paral•leles o de segon ordre o superior. S’ha detectat que la desbromació gradual és la principal via de la fotodegradació dels bromofenols. A més, s’ha identificat també la possible formació de bezenones i hidroxibenzens bromats entre els productes de fotodegradació. S’ha observat que el brom en posició para fa augmentar la velocitat de fotodegradació i que en incrementar el grau de bromació també augmenta lleugerament la velocitat de degradació. Finalment, s’ha observat que el principal efecte de les diferents fonts de llum està vinculat a la velocitat del procés de fotodegradació, però no a la identitat dels fotoproductes formats. S’observa que com més energètica és la radiació utilitzada, més alta és la velocitat de degradació. ESTUDIS DE BIOTRANSFORMACIÓ Per altra banda, amb la finalitat de tenir un coneixement més ampli sobre el destí ambiental del DecaBDE s’ha estudiat la seva biodegradació. D’una banda, s’ha proposat una nova metodologia d’anàlisi mitjançant cromatografia de líquids amb espectrometria de masses en tàndem per a la determinació de possibles productes de biodegradació dels PBDEs (els seus derivats hidroxilats, els OH-PBDEs) i d’altra banda s’ha estudiat la biodegradació in vitro del DecaBDE mitjançant microsomes de fetge de rata. S’ha observat una disminució de la quantitat del compost original durant la biodegradació, la qual cosa significa que es produeix biotransformació. No obstant això, no s’ha pogut detectar cap producte de biodegradació. Es creu que els metabòlits del DecaBDE poden tenir una possible interacció amb els components cel•lulars, que fa més difícil la seva detecció en les condicions experimentals de la metodologia utilitzada.
This thesis presents the study of degradation of two classes of brominated flame retardants (polybrominated diphenyl ethers (PBDEs) and bromophenols) by means of spectroscopic, chromatographic and chemometric methods. We studied two types of degradation: photodegradation and biodegradation Photodegradation Study A general procedure for the study of complex photodegradation processes of environmental pollutants based on chromatographic and spectroscopic monitoring and chemometric method is proposed. Multivariate curve resolution-alternating least squares (MCR-ALS) has been used to resolve concentration profiles and pure spectra of species involved in the photodegradation process and, hence, to elucidate the photodegradation mechanism and to propose the chemical structure of the main photoproducts. In this work are also proposed new data fusion structures (chromatographic (HPLC-DAD-MS) and HPLC /spectroscopy) and related analysis tools that improve the capability to identify the photoproducts formed and the accuracy in the description of the mechanism driving the photodegradation process Based on the proposed methodology a description of the process of photodegradation of decaBDE and six bromophenols and an evaluation of the effect of various factors (solvent polarity, degree of bromination, radiation source ...) on the kinetics and nature of the products formed have been provided. Biotransformation Study In order to have better knowledge about the environmental fate of DecaBDE we have also studied their biodegradation. On the one hand, we have proposed a new methodology for the analysis and determination of possible biodegradation products of PBDEs (hydroxylated derivatives, the OH-PBDEs) by means of liquid chromatography coupled to mass spectrometry. Furthermore we studied the in vitro biodegradation of DecaBDE using rat liver microsomes. Decrease in the amount of original compound during biodegradation was observed, which means that biotransformation occurs. However, biodegradation products were not detected. This indicates that DecaBDE metabolites may have a potential interaction with cellular components, which makes it difficult to detect under the experimental conditions of the methodology used.

The presence of priority and emerging flame retardants (FR) in the environment deserve attention since many of these substances are toxic and persistent. The aim of this thesis was to evaluate the occurrence and impact of priority and emerging flame retardants in the aquatic environment. To accomplish this main objective, the present thesis involved the development of multiresidue methods for the analysis of different FR families in water, sediment, dust and sewage sludge and the application of developed methods for FR monitoring in rivers (UK and Spain) and wastewater treatment plants (WWTPs). Firstly, a multiresidue method based on gas chromatography (GC) coupled to quadrupole mass spectrometry (MS) was developed to determine organophosphorus flame retardants (OPFRs), polybrominated diphenyl ethers (PBDEs), new brominated flame retardants (NBFRs), bromophenols, bromoanilines, bromoanisoles and bromotoluenes. A comparison of two ionization techniques (electron ionization - EI, and electron capture negative ionization - ECNI) and two acquisition modes (selected ion monitoring – SIM, and selected reaction monitoring - SRM) revealed that GC-ECNI-MS/SIM presented the highest sensitivity at expenses of identification capacity, while GC-EI-MS/MS was the most selective technique, permitting the identification of target compounds at the pg levels. This last method was proposed for the determination of FRs in environmental samples. An extraction method for 8 PBDEs, 9 NBFRs and 10 OPFRs in river water and wastewater was developed based on solid phase extraction using Oasis HLB cartridges. In addition, a passive sampling method for monitoring of OPFRs and NBFRs in surface water was developed using the ceramic dosimeter device with HLB as receiving phase. The passive sampler was efficient for the monitoring of target compounds in river water for a deployment time of about 3 weeks, as evidenced by comparison of results obtained by passive and grab sampling. Furthermore, the extraction of target compounds in sediment, sewage sludge and dust was developed using ultrasound-assisted extraction with ethyl acetate/cyclohexane (5:2, v/v), clean-up with florisil cartridges and analysis by GC-EI-MS/MS. The method proved to be efficient and robust for analysis of target compounds in the studied matrices, as evidenced by the results obtained using spiked samples, a certificated reference material and by participating in an interlaboratory study. Monitoring studies were performed at the River Aire (Yorkshire, UK) and at three Spanish rivers (Nalón, Arga and Besòs). In all cases, samples were collected in several points alongthe rivers, fromthe sourceto the mouth, and afterWWTP outputs, in order to identify themost important sourcesof FRs. In addition, influents, effluentsand sludge samples from five Spanish WWTPs were analyzed forevaluatingthe impact of WWTPs as a source ofFRto receiving waters. Among all FR studied, OPFRswerethe most ubiquitouscontaminants in surface waters, andWWTPeffluents wereindicated as the main source ofthese compounds.BDE-209 was themost abundantPBDEcongenerand was detected in water inthe River Aire (UK),in sediments fromthe River Besòs (Catalonia)and in sewage sludge.Low frequency of detection wasobserved for NBFRs in the studied riversand WWTPs.The minor presence of NBFR in the aquaticenvironment pointsto the impression thateither thesecompounds havenotbeen used in Spain or the UK or eitherthatthey have not been used long enough or atsufficient amounts to pose an environmental problem.A toxicity testperformed with Daphniamagnarevealed that OPFRs toxicity (EC50) waswell correlated with their lipophilicity (log Kow), that these compoundspresent similar mode of actionand thattheir joint effects are additive.This mean that joint toxicity of OPFRs at lowconcentrations can produce toxic effects in theaquatic organisms,andsomixturesof these contaminantsmust be considered in risk assessmentstudies. Finally, theriskassessment performed for the studied rivers indicated no risk associated to observedOPFR levels in waters. However, apotential risk foraquatic organismswas estimatedfor the River Aire (UK) associated tothehigh concentrationsof BDE-209 in water.
El objetivo de la presente tesis consistió en el desarrollo de métodos para el análisis multiresiduo de distintas familias de retardantes de llama en matrices ambientales, y su aplicación en estudios de vigilancia ambiental. Entre los diferentes métodos instrumentales desarrollados, el método basado en la cromatografía de gases acoplada a la espectrometría de masas en modo tándem (GC-EI-MS/MS) fue el más adecuado para el análisis de ocho éteres de polibromodifenilo (PBDEs), nueve nuevos retardantes de llama bromados (NBFRs) y diez retardantes de llama organofosforados (OPFRs) en las matrices ambientales propuestas en este estudio. Para el análisis de agua, se desarrolló un método basado en la extracción en fase sólida utilizando cartuchos HLB. Además, se desarrolló un método de muestreo pasivo para la determinación de cuatro OPFRs y dos NBFRs en agua de río utilizando un muestreador “ceramic dosimeter” y HLB como fase receptora. Para el análisis de sedimentos, lodos de depuradora y polvo, se desarrolló y validó un método utilizando la extracción líquido-sólido en un baño de ultrasonidos con acetato de etilo/ciclohexano (5:2, v/v), y purificación de los extractos con cartuchos florisil. El estudio de vigilancia ambiental incluyó la determinación de los compuestos objeto de estudio en 4 ríos de Inglaterra y España y cinco depuradoras en Catalunya. Se analizaron aguas y sedimentos de los ríos e influentes, efluentes y lodos de las depuradoras. Se observó que los OPFRs son los compuestos más ubicuos y más abundantes en todas las muestra ambientales, mientras el BDE-209 se detectó en los ríos y en los lodos de las depuradoras. Los demás PBDEs, y el DBDPE, HBB, PBEB, PBT, EHTBB, BTBPE y BEHTBP se detectaron con una menor frecuencia. Los estudios de toxicidad con Daphnia magna indicaron que mezclas de OPFRs poseen toxicidad aditiva. Se llevó a cabo la evaluación del riesgo para los distintos ríos estudiados y se observó que no hay un riesgo asociado con los niveles de los OPFRs presente en las aguas, pero se observó un riesgo asociado a la presencia del BDE-209 en las aguas del río Aire en Inglaterra.

Thesis (MTech. degree: Environmental Management.)--Tshwane University of Technology, 2012.
Determines the presence and levels of common brominated flame retardants (BFRs) in surface water and sediments in Jukskei River catchments with the aim of identifying potential pollution sources using Geographical Information System (GIS) land use map in order to provide baseline data required to protect water resources against such hazardous chemicals.

Thesis (DTech. degree: Environmental Management)--Tshwane University of Technology, 2012.
Discusses polybromobiphenyls (PBBs) and polybromodiphenyl ethers (PBDEs) are among brominated flame retardants commonly used as additive flame retardants and are now well-known pollutants. They can easily be released from household and office materials if present and tend to settle on dust. Of all the PBDEs congeners, the detection of BDE-209 is considerably more difficult than the lower congeners. Furthermore, there is no available data on the presence of PBBs and PBDEs in indoor dust in South Africa, and, therefore, it was deemed necessary to conduct the present study.