Auswahl der wissenschaftlichen Literatur zum Thema „Flame retardency“

ABSTRACT Layered double hydroxides (LDHs), inorganic clay materials with mixed metals present in the structure along with some interlayer cations, have immense potential for use as a filler in rubbers. We report the preparation and properties of a set of novel nanocomposites consisting of a LDH dispersed in carboxylic–acrylonitrile–butadiene rubber (XNBR). We succeed in obtaining significantly improved physical properties by altering the chemical structure of a LDH with Zn and Al ions (Zn-Al LDH). In particular, we discover a significant reinforcing effect. This occurs despite the size difference between the LDH and traditional reinforcing fillers such as precipitated silica and carbon black. Both the elastic modulus and tensile strength increase. This increase is a function of the LDH concentration and, reaches a maximum value when the LDH concentration is at 100 phr. Experimental evidence suggests that this reinforcing effect is due to direct ion-to-ion interaction between the filler and the matrix. In addition, we report that the presence of the nanofiller positively affects the flame retardence and thermal decomposition of the nanocomposites. We attribute this effect to the presence of a layer formed by the nanofiller.

The study explores the effects of the flame-retardant properties of nano-particles on water-based fire-retardant coatings, which include the effects on thermal stability and combustion properties. The coating used by the paper is acrylate resin (VAC), which is added with 3 basic components, including fire-retardant ammonium polyphosphate, pentaerythritol and melamine (APP-PER-MEL), to form an itumescent fire retardant (IFR). Then the fire retardent is added with magnesium hydroxide (Mg(OH)2, MH) nano-particles, multiwall carbon nanotubes (MWNT) and zinc borate (ZB) nano-powders of different concentrations, to form water-based fire-retardant coatings. By adjusting and controlling the concentration ratios of flame retardant to the 3 kinds of nano-particles with different profiles, the study analyzes the fire-retardant multiplying effect of nano-particles on water-based coatings. The nano-coatings mixed in special proportion are coated on plywood. Through thermogeavimetric analyzer (TGA) and cone calorimeter (CCT), the study inspects the thermal stability and combustion properties of water-based fire-retardant nano-coatings. The experimental results show that when the fire-retardant nano-coating composed of MH of concentration 28% and MWNT of concentration 2% is compared with the fire-retardant coating added with flame retardant only, the amount of residue can be increased by around 80% at combustion temperature 580°C. Besides, when the fire-retardant nano-coating composed of MH of weight concentration 28% and MWNT of weight concentration 2% is compared with the fire-retardant coating added with flame retardant only, the maximum heat release can be decreased by about 15%. The time required for this fire-retardant nano-coating to achieve maximum heat release is delayed by around 70 seconds when compared with other samples. Besides, the char-layered structure formed during thermal decomposition of nano-coating is more compact than the char-layered structure of water-based coating composed of the flame-retardant APP-PER-MEL components only. Therefore, nano-coatings can effectively decrease the transfer of heat and inflammable volatiles to plywood surface, and can enhance the flame retardant performance of plywood.

The introduction of thermal storage materials into wallboard can help to control the temperature fluctuations in the heating and cooling of a building. Thermal storage materials absorb or release heat in defined tempera ture ranges. Wallboard was treated with thermal storage materials, including hexadecane, 1-dodecanol, undecylenic acid, coconut oil and silicone wax. These treatments involved absorption of the compounds into the wallboard. The de sired uptake of material into wallboard was approximately twenty-five percent. The uptake rate for silicone was lower than for the other materials. Most of the energy storage materials are organic, therefore their odor, smoke production, and flammability are a concern. The flammability properties of wallboard samples containing these materials were studied using the E-662 NBS Smoke Chamber and the E162 Radiant Panel Test. The results showed that silicone wax, undecylenic acid and coconut oil treated wallboard samples have superior flame retardent properties compared to wallboard treated with hexadecane, and 1-dodecanol. Silicone wax has a lower latent heat for the phase change as measured by differential scanning calorimetry (DSC) as compared with the other materials. To obtain better flammability properties of treated wallboard, the surface was coated with an epoxy paint containing aluminum trihydrate or magnesium hydroxide. Radiant Panel studies showed a major reduction in flame spread fac tor (Fs) and heat release factor (Q), compared to treated wallboard. However, NBS Smoke Chamber studies in the flaming and non-flaming mode did not show improvement in smoke generation for coated samples. NBS Smoke Cham ber results showed that silicone treated wallboard without any coating yielded lower smoke in the non-flaming mode over other energy storage materials, even when protected by a flame retardant paint. Dodecanol showed lower smoke pro duction in the flaming mode versus other samples.

Antibacterial activity and fire retardation are equally desired for protective clothing. For achieving this, AgNP and MgO are independently researched as nanofillers in Polyurethane based electrospun nanofibers and their synergistic effect is scarcely addressed. This article reports synthesis and characterization of MgO of 70.01 nm and AgNP of 51 to 76 nm by solution combustion and hydrothermal routes respectively and their incorporation in electrospinning of Polyurethane. Flow rate 1 ml/hr, applied voltage 13 kV, tip to collector distance 15 cm were adopted for the electrospinning. Nanofibers of 65 nm were obtained for PU/MgO (3 wt. %) and 106 nm for PU/MgO (3 wt. %)/Ag (1 wt. %). Addition of MgO increased the melting point, after flame time and afterglow time. Incorporation of AgNP improved antibacterial activity. PU/MgO/Ag (2 wt. %) exhibited zone of inhibition of 2.1 cm and 3 cm against E. Coli and S. Aureus, respectively.

The concept of a unique ceramifiable Ethylene vinyl acetate (EVA) based polymer composite was based on the incorporation of inorganic compounds such as aluminium hydroxide, calcium carbonate, muscovite mica, and calcined kaolinite within a 95 percent EVA/ 5 percent Polydimethylsiloxane (PDMS) polymer matrix such tha t upon heating to elevated temperatures of about 1000 oC, a solid end-product with ceramic-like properties would be formed. The ceramifiable EVA based polymer composite was developed to be used as electric cable insulation or sheath as the formation of a ceramic based material at elevated temperatures would provide flame retardant properties during fire situations. The flame retardant properties at elevated temperatures would ensure that the insulation remains at such temperatures due to some of the properties of the resultant ceramic such as reasonably high flexural strength, high thermal stability, non-reactivity and high melting point. During a fire this would ensure that flames would not be propagated along the length of the cable and also protect the underlying conducting wires from being exposed to the high temperatures of the fire. Its application as a cable insulation also required that the material functions as a cable insulator under ambient temperature conditions where the ceramifiable polymer composite should retain certain polymer properties such as the post-cure tensile strength (MPa), degree of polymer elongation (percent), thermal expansion, thermal slacking, limited oxygen index and electrical insulation. This study made use of a composite experimental design approach that would allow for the optimization of the amounts of the additives in the ceramifiable polymer composite giving both the desired mechanical properties of the material under normal operating temperatures as a polymer and also as a ceramic once exposed to elevated temperatures. The optimization of additives used in the ceramifiable polymer composite was done by using a D-optimal mixture design of experiments (DoE) which was analyzed by multiple linear regression.

L'élimination définitive des véhicules hors d'usage constitue une problèmatique environnementale mondiale. Il existe en Europe des entreprises dédiées au démontage et à la récupération de leurs composants qui peuvent alors être réutilisés, parmi lesquels on trouve notamment les déchets plastiques.Dans la première partie de cette recherche, il a été proposé de traiter ces déchets plastiques par un procédé pyrolytique afin de les transformer en déchets solides, à utiliser dans le cadre des additifs dans un système ignifuge dans une matrice polypropylène.Les résidus de véhicule ont ainsi été séparés en utilisant les méthodes d'essai standard pour la densité et la gravité spécifique, puis ont été caractérisés et enfin incorporés dans un processus de pyrolyse thermique aboutissant à la formation d'un résidu pyrolytique solide (RSP). Le RSP fut ensuite incorporé à un mélange de polymères (polypropylène, polyphosphate d'ammonium et pentaérythritol).Les propriétés thermiques, mécaniques et d'inflammabilité ont alors été évaluées par analyse thermogravimétrique, module d'élasticité, résistance à la traction, pourcentage de déformation et indice limite d'oxygène.Dans la deuxième partie de cette recherche, il a été déterminé et comparé si les déchets solides traités thermiquement (RS-T), issus de la pyrolyse des déchets plastiques, les cendres volcaniques (CV) et les cendres de balle de riz (CR) ont une action synergique lorsqu'ils sont ajoutés aux additifs ignifuges de polypropylène (tels que le polyphosphate d'ammonium et le pentaérythritol). Ces matériaux ont été caractérisés par analyse d'adsorption d'azote (méthode de Brunauer-Emmett-Teller), fluorescence X et diffraction des rayons X. La présence abondante de SiO2 et Al2O3, qui sont considérés comme des minéraux ignifuges, a été déterminée.Des composites à matrice polymère composés de polypropylène, de polyphosphate d'ammonium, de pentaérythritol et de matériaux CV, CR et RS-T (à 1% à 9% de concentration) ont été synthétisés. La stabilité thermique et la résistance au feu des mélanges de polymères obtenus ont été évaluées par l'indice limite d'oxygène, l'analyse thermogravimétrique et la calorimétrie à cône. Il a été constaté que ces matériaux ont une action synergique avec les additifs ignifuges au vu de l'augmentation de la résistance au feu mesurée.Dans la dernière partie de cette recherche, l'influence des zéolithes naturelles obtenues à partir des cendres du volcan Ubinas, en tant qu'agents synergiques dans un système ignifuge, a été étudiée. Quatre zéolithes ont été synthétisées à partir de cendres volcaniques calcinées et non calcinées, puis ont été placées dans une solution alcaline à trois températures de synthèse. Les zéolithes ont ensuite été caractérisées par diffraction des rayons X, analyse par adsorption d'azote (méthode Brunauer-Emmett-Teller) et microscopie électronique à balayage.Des mélanges de polymères de polypropylène ont alors été préparés avec du polyphosphate d'ammonium, du pentaérythritol et les zéolites à 1, 5 et 9%. Leur stabilité thermique et leur résistance au feu ont été évaluées par analyse thermogravimétrique, indice limite d'oxygène, test d'inflammabilité verticale ULV-94 et calorimétrie à cône, leur structure morphologique a été testée par microscopie électronique à balayage. Nous avons observé que la température de synthèse et l'utilisation de cendres volcaniques calcinées et non calcinées ont une influence sur les caractéristiques des zéolithes et sur leur action synergique avec les retardateurs de flamme et donc, sur leurs propriétés ignifuges
The final disposal of vehicles at their end-of-life is generating a world environmental problem. Nowadays, in Europe there are companies dedicated to the disassembly and recovery of the components that can be reused, being plastic wastes among these components. Thus, in the first part of this research, it was proposed to treat these plastic wastes through a pyrolytic process in order to transform them into solid wastes, to be used as part of the additives in a flame retardant system for a polypropylene matrix. Vehicle residues were segregated according to their densities and characterized. They were subsequently incorporated into a thermal pyrolysis process giving, as a result, a solid pyrolytic residue (RSP). Using the RSP, the polymer blends were prepared composed of polypropylene, ammonium polyphosphate and pentaerythritol. Their thermal, mechanical and flammability properties were evaluated by thermogravimetric analysis, modulus of elasticity, tensile strength, percentage of deformation and the limiting oxygen index.In the second part of this research, it was determined and compared whether the heat treated solid waste from the pyrolysis of plastic waste of vehicles (RS-T), volcanic ash (CV) and rice husk ash (CR) have any synergistic action when added to polypropylene flame retardant additives (such as ammonium polyphosphate and pentaerythritol). These materials were characterized by nitrogen adsorption analysis (Brunauer-Emmett-Teller method), X-ray fluorescence and X-ray diffraction. The abundant presence of SiO2 and Al2O3 was determined, which are considered flame-retardant minerals. Polymer matrix composites were synthetized, which were composed of polypropylene, ammonium polyphosphate, pentaerythritol and CV, CR and RS-T materials (at 1% to 9% by wt.). The thermal stability and fire resistance of the synthesized polymer mixtures were evaluated through the limiting oxygen index, thermogravimetric analysis and cone calorimetry. It was determined that these materials have a synergistic action with flame-retardant additives as an increase in their fire resistance has been demonstrated.In the final part of this research, the influence of natural zeolites obtained from ashes of the Ubinas volcano, as synergistic agents in a flame-retardant system, has been studied. Four different zeolites were synthesized from volcanic ash, including calcined and not calcined ashes, being placed in an alkaline solution at three synthesis temperatures. Zeolites were characterized by X-ray diffraction, nitrogen adsorption analysis (Brunauer-Emmett-Teller method) and scanning electron microscopy. Polypropylene polymer blends were prepared with ammonium polyphosphate, pentaerythritol and the zeolites at 1, 5 and 9% (by wt.). Their thermal stability and fire resistance were evaluated by thermogravimetric analysis, limiting oxygen index, ULV-94 vertical flammability test and cone calorimetry. Their morphological structure was tested by scanning electron microscopy. It was determined that the synthesis temperature and the use of calcined and non-calcined volcanic ashes has an influence on the characteristics of zeolites and on their synergistic action with flame retardants and therefore, on their flame-retardant properties

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardant, which has been widely used around the world to meet fire safety regulations for fabrics, furnishings, electronics and vehicles since the 1970s. During the life-cycle of the product, PBDEs leach out into indoor air and dust. From there they are transported into the wider environment, and bioaccumulate through food chains. The human body burden of PBDEs increased dramatically from the 1970s until the 1990s as a result of this wide use and their lipophilic and persistent character. In 2009, the Stockholm Convention to protect human health and the environment from persistent organic pollutants, added PBDEs to its list of chemicals for which production, import, export and use should be eliminated. However, the effects of such measures are slow to impact levels in human tissue. Furthermore, recovery and recycling of electronics is an additional newer source of exposure. Potential adverse human health effects of PBDE body burden include reproductive toxicity, neurotoxicity, endocrine activity, DNA damage and immune effects. Aim The aim of this study was to investigate human body burden of polybrominated diphenyl ether (PBDE) flame retardants, PBDE sources and exposure pathways. This was divided into three more specific objectives: (a) To measure current UK human body burdens of PBDE and their contributors, (b) To investigate concentrations of PBDEs in UK diets and influencing factors, and (c) To investigate concentrations of PBDEs in UK indoor dusts and influencing factors. Thesis Summary This doctoral thesis by published works presents four articles that addressed those objectives, investigating current dietary and indoor environment exposure sources and pathways that lead to human PBDE body burden. The study centred on a crosssectional cohort in the North East of England. A short pre-screening questionnaire identified volunteers who could be expected to provide a divergent range of exposures. The study recruited individuals to potentially reflect low, medium and high levels of exposure to PBDEs, such as oily fish eaters and vegetarians, and those iv with possible occupational exposure. 20 study participants were selected: 10 cohabiting couples (10 males and 10 females) aged 26-43 years, living in the North East of England. Samples of matched serum, human milk, 24 hour duplicate diet and indoor dust from living areas, bedrooms, vehicles and workplaces were collected and anthropometric measurements taken. Seven day food and activity diaries, food frequency and lifestyle exposure questionnaires and room surveys were also completed. The first article presents the findings of a systematic review into the relationships between diet and indoor environment exposure and human body burden to PBDEs. The second article presents concentrations of PBDE and polybrominated biphenyl in participants' serum and milk. It also compares the current findings with global concentrations and previous UK measurements taken prior to EU use restrictions. A risk assessment for infant intake of PBDE via milk is included. Relationships between anthropometric information and body burden are explored. The next article presents concentrations of PBDEs (and a range of other persistent organic pollutants (POPs) of interest) measured in 24 hour duplicate diet samples. These measurements are compared with estimations of adult dietary exposure derived from the Food Standards Agency's Total Diet Study 2011/12. Strengths and weaknesses of both methods were explored. Both sets of findings were then compared with previous UK dietary exposure estimates as well as estimates from around the globe. Temporal changes in dietary exposure to the POPs were explored. The final article presents the concentrations of PBDEs in the indoor dusts for the cohort and findings from the room surveys, diaries and questionnaires. Together with the body burden and duplicate diet exposure findings previously presented, the influence of diet, indoor environments, behaviour and anthropometrics on the PBDE body burdens of the cohort are explored. Based on these findings, recommendations for reducing PBDE body burden are made. For each article I discuss its contribution to the literature and a critique of the method. To close I reflect on my individual contribution to each article.

This thesis deals with liquid aprotic electrolytes based on sulfolane with added flame retardant. The theoretical part of the thesis explains concepts - mainly aprotic electrolytes, flame retardants, and their practical use. It also discusses lithium - ion accumulators and materials used in them while focusing on the electrolyte function. The practical part of the thesis aims to measure the properties of aprotic electrolytes: their conductivity, potential window and flashpoint. It also contains a review of the measurement results.

碩士
中央警察大學
警政研究所
85
In recent years, a series of major fires cause serious damages and lifeloss in our country. The investigations find that the major factor to cause life and properties loss is the combustible interior finishes contribute fire to expand and propagate. The fire law which revised on Oct, 11, 1995 regulate the use of flame retardent materials. But the rules of identification and certification are still absent. For this reason, the certification procedure and judgement standards will be investigated based upon the comparative study on the regulations among Japanese fire law, Amreican building regulations and our Chinese National Standards. As we know, the smoke is the main reason of death from lots of examples, and prove to the flame retardent rules. Therefore, the method of ASTM E 662 will be used to explore the optical density of samples which complies with Japanese standards by means of flaming and nonflaming patterns. The results can be adjusted to layout a direction to establish the flame retardent rules in our country reasonly.