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One of the major classes of polymer matrix resins under consideration for structural composite applications in the infrastructure and construction industries is vinyl ester resin. Vinyl ester resin is comprised of low molecular weight poly(hydroxyether) oligomers with methacrylate endgroups diluted with styrene monomer. The methacrylate endgroups cure with styrene via free radical copolymerization to yield thermoset networks. The copolymerization behavior of these networks was monitored by Fourier Transform Infrared Spectroscopy (FTIR) at various cure conditions. Reactions of the carbon-carbon double bonds of the methacrylate (943 cm-1) and styrene (910 cm-1) were followed independently. Oligomers possessing number average molecular weights of 700 g/mole were studied with systematically increasing levels of styrene. The Mortimer-Tidwell reactivity ratios indicated that at low conversion more styrene was incorporated into the network at lower cure temperatures. The experimental vinyl ester-styrene network compositions deviated significantly from those predicted by the Meyer-Lowry integrated copolymer equation at higher conversion, implying that the reactivity ratios for these networks may change with conversion. The kinetic data were used to provide additional insight into the physical and mechanical properties of these materials. In addition to establishing the copolymerization kinetics of these materials, the development of halogen free fiber reinforced vinyl ester composites exhibiting good flame properties was of interest. Flame retardant vinyl ester resins are used by many industries for applications requiring good thermal resistance. The current flame-retardant technology is dependent on brominated vinyl esters, which generate high levels of smoke and carbon monoxide. A series of halogen free binder systems has been developed and dispersed in the vinyl ester to improve flame retardance. The binder approach enables the vinyl ester resin to maintain its low temperature viscosity so that fabrication of composites via Vacuum Assisted Resin Transfer Molding (VARTM) is possible. The first binder system investigated was a polycaprolactone layered silicate nanocomposite, which was prepared via intercalative polymerization. Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) data indicated a mixed morphology of exfoliated and intercalated structures. The mechanical properties and the normalized peak heat release rates were comparable to the neat vinyl ester resin. Alternative binder systems possessing inherent flame retardance were also investigated. A series of binders comprised of novolac, bisphenol A diphosphate, and montmorillonite clay were developed and dispersed into the vinyl ester matrix. Cone calorimetry showed reductions in the peak heat release rate comparable to the brominated resin. / Ph. D.

This thesis has focused on the synthesis and characterization of amino functional monomers, principally monomers containing aryl phosphine oxide units. Utilization of these monomers was demonstrated in various types of linear and network polymerizations. The diamines monomers included bis(3-aminophenyl) methyl phosphine oxide (DAMPO), bis(3-aminophenyl) phenyl phosphine oxide (DAPPO), bis(3-aminophenoxy phenyl) phenyl phosphine oxide (BAPPO) and bis(3-aminophenoxy phenyl) methyl Phosphine oxide (BAMPO). From these monomers high molecular weight poly(ether imides), polyurea-urethanes, poly(arylene ether ketones) poly(arylene ether sulfones) and poly(arylene ether phosphine oxides) were. Internal and external fire testing methodologies showed that the new polymers containing phosphine oxide units were fire resistant while maintaining the desirable physical characteristics of carefully selected control systems. In addition, suitable curing schedules for epoxy networks were determined by using dielectric monitoring techniques. The curing rates varied with the structure of the monomers and were slowest for the deactivated control (4,4'aminophenyl sulfone). Epoxy networks containing aryl phosphine oxide units had higher char yields in dynamic thermogravimetric analyses than control specimens. This correlated with their superior flame resistance. The brittle epoxy matrices were subsequently modified with reactive or non-reactive thermoplastic polymers in order to improve their fracture toughness. Poly(ether imides) and poly(ether sulfones) showed good phase separation behavior with tetrafunctional epoxy matrices during the curing reactions, as confirmed by scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA). Mechanical tests showed that reactive thermoplastic modification of the epoxy networks improved the fracture toughness of the systems, without noticeable decreases in other characteristics such as flexural modulus. Reactive systems also maintained chemical resistance in contrast to non-reactive thermoplastic controls. / Ph. D.

<p>Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardant chemicals that are added to plastics, electronic components, furniture foam, and textiles to reduce their combustibility. Of the three commercial mixtures historically marketed, only DecaBDE, which is constituted almost entirely (~97%) of the fully brominated congener decabromodiphenyl ether (BDE-209), continues to be used in the U.S. today. While decaBDE is scheduled for phase-out in the U.S. at the end of 2013, exposures to BDE-209 and other PBDEs will continue into the foreseeable future as products that contain them continue to be used, recycled, and discarded. In addition, decaBDE use continues to be largely unrestricted across Asia, although restricted from use in electronic equipment in Europe. </p><p>Despite limits placed on PBDE uses, they are ubiquitous contaminants detected worldwide in humans and wildlife. Major health effect concerns for PBDEs come largely from evidence in laboratory rodents demonstrating neurotoxicity, reproductive and developmental impairments, and thyroid disruption. The potential for PBDEs, particularly BDE-209, to disrupt thyroid regulation and elicit other toxic outcomes in fish is less clear. Thus, the overall objective of this thesis research was to answer questions concerning how fish, as important indicators of overall environmental health, are metabolizing PBDEs and whether and how PBDEs are disrupting thyroid hormone regulation. The central hypothesis was that PBDE metabolism in fish is mediated by iodothyronine deiodinase (dio) enzymes, which are responsible for activating and inactivating thyroid hormones, and that PBDE exposures are causing thyroid system dysfunction across fish life stages. </p><p>Under the first research aim, in vitro experiments conducted in liver tissues isolated from common carp (Cyprinus carpio) suggested a role for dio enzymes in catalyzing the reductive debromination of PBDEs. Carp liver microsomes efficiently debrominated BDE-99 to BDE-47, and enzymes catalyzing this reaction were associated predominantly with the endoplasmic reticulum (i.e., microsomal fraction) where dio enzymes are located. Competitive substrate experiments in carp liver microsomes also demonstrated that rates of BDE-99 debromination to BDE-47 were significantly inhibited upon challenges with 3,3',5'-triiodothyronine (rT3) and thyroxine (T4). This finding supported the hypothesis that enzymes involved in the metabolism of PBDEs may have high affinities for thyroid hormones. Indeed, experiments to determine apparent enzymatic kinetics (apparent Vmax and Km values) of BDE-99 hepatic metabolism suggested that enzymes responsible for the catalytic activity appeared to have a higher affinity for native thyroid hormone than BDE-99. </p><p>The second and third research aims were focused on evaluating BDE-209 accumulation, metabolism, and thyroid toxicity in juvenile and adult life stages of fish using the fathead minnow (Pimephales promelas) as a model. BDE-209 bioaccumulated and was debrominated to several reductive metabolites ranging from penta- to octaBDEs in both juvenile and adult fish exposed to BDE-209. In addition, thyroid hormone regulation in juvenile and adult male fathead minnows was severely disrupted by BDE-209 at low, environmentally relevant exposures. In juvenile minnows, the activity of dio enzymes (T4-outer ring deiodination; T4-ORD and T4-inner ring deiodination; T4-IRD) declined by ~74% upon oral doses of 9.8 ± 0.2 µg/g wet weight (ww) food at 3% body weight (bw)/day for 28 days, compared to controls. Declines in dio activity were accompanied by thyroid follicle hypertrophy indicative of over-stimulation and injury. In addition to thyroid disruption, a distinctive liver phenotype characterized by vacuolated hepatocyte nuclei was measured in ~48% of hepatocytes from treated fish that was not observed in controls. </p><p>Under the third research aim, adult male fathead minnows received dietary treatments of BDE-209 at a low dose (95.3 ± 0.41 ng/g-food at 3% bw/day) and a high dose (10.1 ± 0.10 µg/g-food at 3% bw/day) for 28 days followed by a 14-day depuration period to evaluate recovery. Compared to negative controls, adult male fish exposed orally to BDE-209 at the low dose tested for 28 days experienced a 53% and 46% decline in circulating total T4 and T3, respectively, while fish at the high BDE-209 dose tested had total T4 and T3 deficits of 59% and 62%, respectively. Depressed levels of plasma thyroid hormones were accompanied by a 45-50% decline in the rate of T4-ORD in brains of all treatments by day 14 of the exposure. The decreased T4-ORD continued in the brain at day 28 with a ~65% decline measured at both BDE-209 doses. BDE-209 exposures also caused transient, tissue-specific upregulations of relative mRNA transcripts encoding dio enzymes (dio1, dio2), thyroid hormone receptors (TR&alpha, TR&beta), and thyroid hormone transporters (MCT8, OATP1c1) in the brain and liver in patterns that varied with time and dose, possibly as a compensatory response to hypothyroidism. In addition, thyroid perturbations at the low dose tested generally were equal to those measured at the high dose tested, suggesting non-linear relationships between PBDE exposures and thyroid dysfunction in adult fish. Thus, mechanisms for BDE-209 induced disruption of thyroid regulation can be proposed in adult male minnows that involve altered patterns of thyroid hormone signaling at several important steps in their transport and activation. </p><p>A growing body of evidence describing PBDE toxicity in biota, including data generated here, along with studies showing continued and rising PBDE body burdens, raises concern for human and wildlife health. Long delays in removing PBDEs from the market, their ongoing presence in many products still in use, and their active use outside the U.S. and European Union will leave a lasting legacy of rising contamination unless more concerted regulatory and policy actions are taken to reduce future exposures and harm.</p> / Dissertation

O trabalho visou realizar um estudo sobre o comportamento mecânico e de inflamabilidade de estruturas aeronáuticas de interior fabricadas a partir de compósitos reforçados por fibras naturais, especificamente compósitos de resina fenólica com fibras de algodão e de sisal, verificando assim, a possibilidade de substituir compósitos sintéticos. Num primeiro momento, análises experimentais foram executadas para determinar as propriedades mecânicas dos materiais. Em seguida, análises computacionais foram realizadas, empregando as propriedades referentes aos compósitos sintéticos e reforçados por fibras naturais, utilizando critérios de falha e tendo como referência o desempenho do compósito sintético para uma dada estrutura aeronáutica de interior. Além disso, foram efetuadas análises do seu comportamento quanto à inflamabilidade. A incorporação de retardantes de chama foi necessária para que os compósitos reforçados por fibras naturais atendessem aos requisitos de certificação aeronáutica. Após o processo de aditivação, observou-se um aumento do módulo de elasticidade à flexão (55% para o compósito de algodão, 16% para o compósito de sisal) e a diminuição da tensão de ruptura à flexão dos compósitos reforçados por fibras naturais analisados (45% para o compósito de algodão, 55% para o compósito de sisal). No entanto, com o aumento da espessura da estrutura aeronáutica adotada (5,2% para o compósito de algodão, 10,7% para o compósito de sisal), conclui-se que a substituição do compósito sintético pelo natural seria viável. Isto acarretaria em um aumento de massa em 6,2%, caso a estrutura fosse fabricada em compósito reforçado por fibra de sisal. Finalmente, constatou-se que a fração mássica de aditivo utilizada tem grande potencial de otimização e, que a eficiência dos compósitos reforçados por fibras naturais ainda pode ser melhorada. / This dissertation has aimed to study the mechanical behavior and the flammability of aeronautical interior structures manufactured from composites reinforced by natural fibers, specifically phenolic resin and cotton and sisal fibers composites, verifying the possibility of synthetic composites replacement. Firstly, experimental analyses were performed to determine the mechanical properties of the materials. Then, computational analyses were carried out, using properties of synthetic composites and composites reinforced by natural fibers. Also, failure criteria were applied, considering the synthetic composite performance of an interior aeronautical structure as reference. Furthermore, the behavior regarding flammability was analyzed. The addition of flame retardants was necessary for the composites reinforced by natural fibers in order to attend the aeronautical certification requirements. After the addition of flame retardants, an increase in the flexural modulus of elasticity (55% for the cotton composite, 16% for the sisal composite) and a decrease in the flexural stress at break (45% for the cotton composite, 55% for the sisal composite) were observed. However, with an increase of the thickness of the aeronautical structure (5.2% for the cotton composite, 10.7% for the sisal composite), it was concluded that the replacement would be feasible, which would lead to a increase of the mass equal 6.2% for the sisal fiber composite. Finally, it was evidenced that the used flame retardant mass fraction has a great potential for optimization and that the natural composites efficiency can be improved.

Flamskyddande kemikalier används idag inom en hel del olika områden. Ett stort område är textil, där hemtextil är dominerande. Det finns en mängd olika typer av flamskydd på marknaden. Alla har till uppgift att sakta ner brandförloppet eller helt förhindra att en brand uppstår. De halogenerade flamskydden är de mest effektiva men har många kopplingar till miljöproblem. De fosforbaserade och kvävebaserade är snällare mot miljön med mindre effektiva än de halogenerade. Ofta kombineras de fosfor- och de kvävebaserade flamskydden för att få bättre egenskaper på slutprodukten.Denna rapport innehåller, på uppdrag av FOV Fabrics AB, en kartläggning av flamskyddsmarknaden i Europa, med fokus på de produkter som kan tillämpas på material av polyester och polyamid. Målet är att finna flamskyddsmedel för dessa som dessutom är tvättbeständiga samt relativt ofarliga för miljön. De produkter som anses relevanta testas sedan gentemot den internationella brandstandarden, ISO 6941, vilket innebär att en provbit belagd/impregnerad med kemikalien fästs vertikalt i en anordning. Tygprovet utsätts sedan för en horisontell låga i tio sekunder. Därefter görs mätningar på exempelvis den tid det tar tills tygprovet slocknat, samt andel skadat material. Rapporten innehåller även information om övriga tester som utförts, såsom drag- och rivstyrka, tvättbeständighet och färgförändringsmätningar på de produkter som visat tillfredsställande resultat i brandtesterna.Av de nio produkter vi testade fann vi varierade resultat. En del uppfyllde inte våra krav med avseende på flamskydd, och en del visade sig ha mycket dålig tvättbeständighet. Vi fann dock några produkter för båda materialen, två för polyester och fyra för polyamid, som är aktuella att göra vidare tester på. Eventuellt kvävs justering av koncentrationer och appliceringsrutiner för att möta FOV:s önskemål.Flame-retardant chemicals are used today in a lot of different areas. A large area is textiles, where upholstery textiles are dominant. There are many different types of flame retardants on the market, and the purpose is to slow down or completely prevent a fire. The halogenated flame retardant is the most effective but has many links to environmental problems. The phosphorous and nitrogen-based is kinder to the environment but often with less efficiency than the halogenated. When phosphorous and nitrogen flame retardants are combined, the two often get better features.This report, commissioned by the company FOV Fabrics AB, contains a scan of the flame retardant market in Europe, focusing on those products that can be applied to textiles of polyester and polyamide. The goal is to find the flame retardant for these materials, which are also wash resistant and has a relatively low environmental impact. The products that are deemed relevant are then tested against the international fire standard, ISO 6941, which means that a test piece, which has been coated/finished with the chemical, is fastened vertically on a device and then ignited by a horizontal flame for ten seconds. Thereafter, measurements are taken as regards to the amount of time before the test piece burns out and the proportion of damaged material. The report also includes information about other tests conducted, such as tensile- and tear strength, wash resistance and color change. These measurements are made on those products which have shown satisfactory performance in regards to the fire tests.Among the nine products we tested, we found varied results. Some did not meet our requirements for fire protection, and some were found to have very poor wash resistance. We found, however, a couple of products for polyester and four products for polyamide which showed such good results that they are relevant for further testing. Adjustment of concentration and application procedures may be adjusted to achieve the requirements of FOV&apos;s specifications. / Program: Textilingenjörsutbildningen

Two organophosphorus compounds, namely diethyloxymethyl-9-oxa-10- phosphaphenanthrene-10-oxide (DOPAC) and diethyl (2,2-diethoxyethyl) phosphonate (DPAC) were applied on cotton cellulose to impart non-carcinogenic and durable (in alkaline washing) flame retardant property to it. Some acidic catalysts, sodium dihydrogen phosphate (NaH2PO4), ammonium dihydrogen phosphate (NH4H2PO4) and phosphoric acid (H3PO4), were successfully used to settle acetal linkage between cellulose and flame retardant (FR) compound. Appreciable limiting oxygen index (LOI) values of 24% and 23.9% were achieved in case of the samples treated with FR compound DPAC along with the combined acidic catalyzing effect of NaH2PO4+H3PO4 and NaH2PO4+NH4H2PO4. A distinguishing outcome of total heat of combustion (THC) 3.27 KJ/g was revealed during pyrolysis combustion flow calorimetry (PCFC) test of the treated sample. In respect of thermal degradation, low temperature dehydration in conjugation with sufficient amount of char residue (30.5%) was obtained in case of DOPAC treated sample. Consistently, the temperature of peak heat release rate (TPHRR) (325°C) of DPAC treated sample supported the expected low temperature pyrolysis in condensed phase mechanism. Subsequent thermogravimetric analysis (TGA) also reported inspiring weight retention% of the treated samples. Furthermore, for both of the flame retardant compounds, effect of different catalysts, considering both individual and combined, effect of solvents, and overall the optimization of the process parameters were studied in detail. / Program: Magisterutbildning i textilteknologi

Persistent organic pollutants (POPs) are toxic chemicals that can be found in various matrices in all corners of the planet, including remote areas such as the Arctic.  Several POPs are known and monitored but given the abundance of new chemicals in commerce about which little is known, chemicals that may be new POPs are constantly being screened for. The use of flame retardants, particularly brominated flame retardants (BFRs), has been increasing for decades. PBDEs and HBCDDs are two types of BFRs that have historically been used in large volumes but recently faced legislative restrictions. However, in order to meet fire safety standards, these BFRs have been replaced by a variety of emerging flame retardants (EFRs) about which little is known especially concerning their toxicity, production volumes, and environmental behavior. The main purpose of this thesis was to investigate the occurrence and fate in indoor and outdoor environments of several EFRs and compare them with PBDEs, HBCDDs, and legacy POPs. Several indoor environments in the city of Stockholm, Sweden were sampled for dust, indoor air, and ventilation system air (Paper II).  Results from these samples revealed a number of EFRs that humans are exposed to and that are emitted from buildings through ventilation systems. These included DDC-CO, DBE-DBCH, PBT, HBB, EHTBB, and BEH-TEBP. PBDE levels seem to be declining compared to previous studies in Stockholm.  Outdoor air and soil were sampled across transects of Stockholm (Paper II) and Birmingham, United Kingdom (Paper III).  Results from these samples showed the presence of many of the same EFRs in the outdoor environment that were found in indoor environments.  Urban pulses in air were discovered for PBDEs in both cities and for some EFRs in Stockholm, indicating that the cities are sources of EFRs to the outdoor environment.  Atmospheric deposition samples were taken at two sites in northern Sweden (Paper I).  Three EFRs (DDC-CO, DBE-DBCH, and BTBPE) and two current-use pesticides (trifluralin and chlorothalonil) were identified, indicating these compounds’ potential for long range transport and global contamination.  Other legacy POPs such as HCH, PCBs, and PBDEs were measured in the deposition samples as well.  The bulk of deposition was comprised of HCH and PCBs with only minor contributions from PBDEs, chlordanes, and emerging compounds.  Finally, passive and active air sampling methods were compared for BFRs in offices in Beijing, China.  Some EFRs were identified in indoor air from China; however, BDE-209 was the most predominant compound found (Paper IV).  Air samples collected with passive samplers generally had measured FR concentrations within a factor of 2-3 of those collected with active samplers. The use of a GFF in the passive samplers resulted in concentrations of particle-bound contaminants such as BDE-209 that were more comparable to those in active samples. The positioning of the PUF in the passive samplers affected the sampling rates for gaseous compounds and particle retention on PUFs was shown to be a large source of uncertainty in passive sampling. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p><p> </p>

Baigiamajame magistro darbe nagrinėjamas priešgaisrinės išsipučiančios dangos porėto ir nedegių liekanų termiškai stabilaus sluoksnio sudarymo principai. Aprašomi užpildai bei kiti komponentai gerinantys dangos termoizoliacines savybes. Taip pat pateikta įvairių užpildų įtaką sudarant apsauginį dažų sluoksnį. Be to, darbe yra aprašyti minimalaus priešgaisrinės dangos sluoksnio, reikalingo plieno konstrukcijoms gaisro metu apsaugoti, skaičiavimai. Metodinėje-tiriamojoje darbo dalyje pateikta priešgaisrinės dangos bandymo atlikimo tvarka ir įranga, šilumos laidumo skaičiavimo metodika. Išnagrinėta koreliacinės-regresinės analizės vertinimo metodika. Praktinėje darbo dalyje analizuojamos priešgaisrinės dangos šilumos laidumo ir dangos termoizoliacinio sluoksnio padidėjimo priklausomybė nuo skirtingai didėjančių gaisro temperatūrų. Taip pat gautiems šilumos laidumo rezultatams atliekama koreliacinė-regresinė analizė. Darbą sudaro 5 dalys: įvadas, analitinė dalis, metodinė-tiriamoji dalis, išvados, literatūros sąrašas. / In the analytical part of this Thesis, the principals of fire resistance intumescent coatings foam and thermally stable char layer forming is presented. The fillers and other components for improving surface thermal properties are discussed. As well as a variety of fillers influence the protective coating analyses. In addition, the work is described the minimum fire protection coating layer of steel structures required for fire protection calculations. In the project part of this Thesis, the procedures and equipment, the heat conduction calculation is given. Moreover, the Thesis fire surface thermal conductivity and thermal insulation coating layer increases dependence on the different ways of rising temperatures in the fire analyses. It is also obtained the result of heat conduction by correlation-regression analysis. Structure: introduction, analytical part, the research part, conclusions and references.