Thesis (Ph. D.)--Institute of Paper Chemistry, 1948. / Bibliography: leaves 84-86.

Retail stores are an environment with a rich diversity of toxic chemicals typically found in consumer products. Among these chemicals, semi-volatile organic compounds (SVOCs) are an important class with great health concerns. Phthalates and polybrominated diphenyl ethers (PBDEs) are high production volume SVOC chemicals pervasively used in plastics and other consumer products. Exposure to them may cause serious adverse health effects, including endocrine disruption. They, however, have not been widely studied in retail environments. In this study, indoor air samples were collected from 15 retail stores in Austin, TX and University Park, PA. Some of these stores were revisited on different temperate seasons to account for weather variability. Indoor concentrations of the most ubiquitous pollutants were correlated with several building characteristics, including retailer type, temperature, and building use characteristics. Collected data shows a wider variety of phthalates and PBDEs, as well as higher indoor airborne concentrations for large department stores as compared to grocery stores, which typically have fewer sources in comparison. / text

A three-compartment model is extended to estimate the fate and transport of DEHP in a realistic residential environment. The model considered eight environmental media (i.e. air, particulate matter with six size fractions, vinyl flooring, carpet, furniture, dust, wall and ceiling). Particle movement (deposition and resuspension), dust removal (vacuuming), indoor cooking, and adsorption/absorption on indoor surfaces are included. The predicted airborne DEHP concentrations at steady state are within 0.1 [microgram]/m³ to 0.6 [microgram]/m³, which are similar to those measured in field studies. After vinyl flooring (the primary source) is removed, it takes 2 years for the indoor airborne DEHP level to reduce 0.01 [microgram]/m³, and the time increases significantly when carpet present. The results indicate that carpets as well as other interior surfaces may be important phthalate sinks and if the only removal mechanism is ventilation, strongly sorbing phthalate may persist for years. Phthalate amount in dust is strongly influenced by the deposition surface. The concentration of DEHP presents 10 times higher in dust on the source (vinyl flooring) than on the sink (furniture), and it takes more than a year for DEHP to reach equilibrium between bulk air and dust. The domestic activity of cooking is then included in the model and it shows that suspended particle concentration has a substantial impact on gas-phase DEHP level indoors, while the influence of ventilation is only to some extent. Three other SVOCs (DMP, BBP and DiDP) are also investigated and their environmental fates show that chemical’s vapour pressure and octanol/air partition coefficient have substantial influences on sorbing mechanisms and the gas phase and airborne concentrations. / text

Di-(2-ethylhexyl)-phthalate (DEHP), an ubiquitous environmental contaminant, has been shown to cause adverse effects on glucose homeostasis and insulin sensitivity in epidemiological studies, but the underlying mechanisms are still unknown. We therefore tested the hypothesis that chronic DEHP exposure causes impaired insulin sensitivity, affects body weight, adipose tissue (AT) function and circulating metabolic parameters of obesity resistant 129S6 mice in vivo. An obesity-resistant mouse model was chosen to reduce a potential obesity bias of DEHP effects on metabolic parameters and AT function. The metabolic effects of 10-weeks exposure to DEHP were tested by insulin tolerance tests and quantitative assessment of 183 metabolites in mice. Furthermore, 3T3-L1 cells were cultured with DEHP for two days, differentiated into mature adipocytes in which the effects on insulin stimulated glucose and palmitate uptake, lipid content as well as on mRNA/protein expression of key adipocyte genes were investigated.We observed in female mice that DEHP treatment causes enhanced weight gain, fat mass, impaired insulin tolerance, changes in circulating adiponectin and adipose tissue Pparg, adiponectin and estrogen expression. Serum metabolomics indicated a general increase in phospholipid and carnitine concentrations. In vitro, DEHP treatment increases the proliferation rate and alters glucose uptake in adipocytes. Taken together, DEHP has significant effects on adipose tissue (AT) function and alters specific serum metabolites. Although, DEHP treatment led to significantly impaired insulin tolerance, it did not affect glucose tolerance, HOMA-IR, fasting glucose, insulin or triglyceride serum concentrations. This may suggest that DEHP treatment does not cause impaired glucose metabolism at the whole body level.

Phthalate esters (PEs) and organophosphate esters (OPEs) are common indoor pollutants frequently detected in environmental (dust, air), personal (hand wipes, diet) and human matrices (urine, serum etc.). In this thesis, mathematical models were used to establish links between intake and body burden for a comprehensive dataset based on a Norwegian study population. Also, the relative importance of different PE uptake pathways was assessed and discussed. Furthermore, the suitability of human nails as an alternative, non-invasive biomonitoring matrix for PEs was investigated. Additionally, information regarding alternative plasticizers to PEs was collected and presented extensively. Results showed that for PEs (paper II), daily intakes based on external exposure media agree with back-calculations using urinary metabolite concentrations, leading to the conclusion that human exposure for the general adult population is well understood and that the most important uptake routes were captured. Overall intake levels are comparable or lower than level presented in recent comprehensive studies and hazard quotients were well below 1 (low risk). As expected, diet was found to be the most important uptake route for all PEs. For lower molecular weight PEs, inhalation becomes a strong contributing pathway whereas for higher molecular weight PEs, dust ingestion was also important. Daily intake based on hand wipes was found to be much lower than the estimated total dermal intake based on air, dust and personal care products, questioning the relevance of hand wipes to represent total dermal exposure. Human nails were found to be unsuitable for replacing urine as a biomonitoring matrix for PEs as internal intake (from blood) cannot explain measured nail concentrations and uptake from air is too slow to reach observed concentrations within a realistic time frame (paper III). Hence, the kinetic links between intake and nail concentrations could not be established. Although exposure to traditional PEs is decreasing, use and body burden of some alternatives are increasing (paper I). Fortunately, most alternative plasticizers have favorable toxicological properties, resulting in low risk for humans. In contrast to PEs, OPEs still remain a group of poorly studied substances in terms of human exposure (paper IV). Due to lack of information regarding human metabolism, reliable links between intake and concentrations in serum and urine could not be established. Modelling results showed that concentrations in serum, and to some extent, urine, were underestimated for 2 compounds. It is likely that a combination of missing intake and suboptimal biomarkers were the cause for this under-prediction. Because of this, further studies regarding human metabolism should be performed for OPEs and potentially more specific biomarkers identified in the future. For PEs, there is a need for more comprehensive datasets to study exposure for high risk groups such as infants and children. Furthermore, dermal uptake remains poorly understood and the uptake of PEs into human nails should be studied in more detail to establish the kinetic links between exposure and body burden. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 4: Manuscript.</p>

CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Anna Hánová Title of diploma thesis: Rheological properties of White Soft Paraffin Consultant: PharmDr. Eva Šnejdrová, Ph.D. This diploma thesis deals with the evaluation of consistency and rheological properties of the Soft Paraffin after viscosity modification by either Liquid or Solid Paraffin. The theoretical part focuses the characteristics and application of the hydrocarbon excipients, their use in pharmacy and comparison with other substances, rheological properties of semisolids and their consistency. Consistency by penetrometry according the Czech Pharmacopoeia 2009 and rheological properties using Kinexus rheometer were measured. Consistency of Soft Paraffin was significantly influenced with 5 % of Liquid Paraffin and 10 % of Solid Paraffin. The result of consistency assessment is significantly influenced by the method of the samples preparation. Rheograms and viscosity curves was constructed. Plastic systems were described in detail by the parameters of power law model and yield stress value. The addition of 5 % of Liquid Paraffin to the Soft White Paraffin caused the decrease of the coefficient of consistency and the flow index. A further addition of Liquid...

CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Hana Jakubíková Title of diploma thesis: Aciclovir release from mucoadhesive polyester matrices Consultant: PharmDr. Eva Šnejdrová, Ph.D. The aim of this diploma thesis was to investigate aciclovir release from polyesters of lactic acid and glycolic acid branched with mannitol, pentaerythritol, dipentaerythritol and tripentaerythritol, and plasticized using ethyl pyruvate or methyl salicylate. Theoretical part sums up the application possibilities of mucoadhesive preparations. Experimental part of thesis deals with aciclovir release from polyester matrices applied on mucous substrate. Short term dissolution experiments of aciclovir were carried out in phosphate citrate buffer of pH 7, 4 at 37 řC. Mucus from porcine stomach was used as model substrate. The amount of aciclovir released was determined spectrophotometrically at 256 nm contrary to a blank sample, and also using HPLC method. Dissolution of aciclovir was affected by molar mass of polyester, and by the type and concentration of plasticizer. Polyester branched with 3 % of tripentaerythritol, and plasticizes by 40 % of methyl salicylate was found to be most suitable carrier of aciclovir for topical application on...

A dissertation submitted to the Faculty of Science University of the Witwatersrand, Johannesburg for the degree of Master of Science / The object of this dissertation is to develop a cost effective plasticiser/water-reducer from tannin extracts which does not retard initial strength development. Model compounds of tannins indicated the suitability of substiuued phenols for this purpose, Catechol with adjacent hydroxide groups gave a good combination of improved workability with compressive strengths equivalent to the control. Combinations with ammonia and torrnaldehyde resulted in some greatly improved performances, but also reduced stability of the additives. Urea and metabisulphite did provide some improvements ai!1ddid not adversely affect shelf life. Some of the tannin extracts tested on their own gave considerate improvements in workability and some strengths. To improve the stability of extract solutions, tannins were modified with urea, metabisulphite, small amounts of potassium hydroxide and a alcohol mixture used for pretreatment. Only the first two listed were consistently effective without producing any disadvantages. They even further improved the concrete performance of condensed tannins in particular. Small additions of TEA or its acetate salt resulted to better one day strengths of the modified tannins. Analytical techniques such as infrared and nuclear magnetic resonance were used to monitor some; modifications of the tannins and their result. A test representing early hydration conditions and X-ray diffraction provided clues to the additives mechanism in its interaction with cement. The additives performance was evaluated by comparison with a leading plasticiser/water-reducer, an independent concrete testing laboratory and conduction calorimetry by a research and testing council. A tannin based plasticiser made largely from local raw materials was quickly accepted during a recession by brick and precast manufactures . / Andrew Chakane 2018

É crescente o interesse e a necessidade de substituição de materiais preparados a partir de matéria-prima obtida de fontes fósseis, por materiais oriundos de fontes renováveis, como os compósitos poliméricos reforçados com fibras naturais. Adicionalmente, é acelerada a geração de descarte de embalagens plásticas no país, comparativamente à reciclagem de materiais. Neste contexto, o presente trabalho consistiu na busca pelo aprimoramento de processos de preparação de compósitos baseados em poli (tereftalato de etileno) reciclado (PET reciclado) e fibras de sisal. As fibras de sisal foram caracterizadas segundo o teor de componentes químicos majoritários, difração de raios X, microscopia eletrônica de varredura (MEV), análise térmica (calorimetria exploratória diferencial (DSC) e termogravimetria (TG)) e espectroscopia na região do infravermelho (IV). O PET reciclado foi caracterizado por DSC, TG, IV e determinação do índice de fluidez. Inicialmente, compósitos de PET reciclado/fibras de sisal foram processados via reometria de torque, com posterior termoprensagem, à temperatura de 260ºC, porém foi observada a decomposição térmica das fibras, ou seja, o recobrimento pela matriz não retardou a decomposição das fibras. Consequentemente, visando uma diminuição da temperatura de fusão do PET reciclado (~265ºC), a fim de evitar a decomposição térmica das fibras durante o processamento, os plasticizantes acetil tributil citrato (ATBC), tributil citrato (TBC), glicerol, óleo de mamona (OM) e óleo de soja epoxidado (OSE) foram acrescentados às formulações dos compósitos. Adicionalmente, polibutadieno hidroxilado líquido (PBHL) foi acrescentado à formulação do material, visando avaliar sua ação como agente compatibilizante/de acoplamento na interface fibra-matriz. Destaca-se que estes plasticizantes foram escolhidos por serem oriundos de fontes renováveis, assim como por possuírem grupos nas respectivas estruturas com afinidade tanto por grupos presentes nos componentes da fibra como na matriz. Desta forma a possível ação dos mesmos como compatibilizantes também foi considerada. Os plasticizantes foram caracterizados por DSC, TG e IV. A exploração de parâmetros de processamento, usando plasticizantes, foi feita misturando os componentes usando pás rotativas, seguido de moldagem por compressão. A composição da mistura e parâmetros de processamento, que levaram ao melhor conjunto de resultados, foi considerada para processamento via reometria de torque/termoprensagem. Os compósitos foram caracterizados por MEV, DSC, TG, absorção de água, e com relação às suas propriedades mecânicas por análise térmica dinâmico-mecânica (DMTA), e ensaios de resistência ao impacto e à flexão. Analisando-se os resultados obtidos, observa-se que, com relação aos diferentes processamentos dos compósitos, a moldagem por compressão foi mais adequada para a preparação dos compósitos de PET reciclado/fibras de sisal, principalmente em relação ao superior desempenho mecânico apresentado por estes materiais, em comparação aos compósitos processados por reometria de torque e posterior termoprensagem. O PET reciclado não reforçado, dentre as propriedades mecânicas apresentadas, não apresentou boa resistência ao impacto, assim como os compósitos preparados a partir dele, ou seja, a propriedade do PET reciclado foi predominante nos compósitos. No entanto, o uso de plasticizantes viabilizou não só o processamento dos compósitos à menor temperatura, assim como aumentou a molhabilidade da fibra pelo polímero, por diminuir a viscosidade da mistura. Ainda, no geral, as micrografias das superfícies de fratura dos compósitos demonstraram uma boa adesão na interface fibra-matriz, indicando atuação dos plasticizantes também como compatibilizantes entre fibra e matriz. Destaca-se que, no geral, os resultados de resistência à flexão e DMTA apontaram no sentido de que a presença das fibras e plasticizantes levaram a materiais menos rígidos e mais flexíveis. Dentre os compósitos, pode-se considerar que a mistura PET reciclado/fibras de sisal/glicerol/ TBC apresentou o melhor desempenho mecânico, que levou, no geral, ao melhor resultado de resistência ao impacto, boa resistência à flexão e deformação na ruptura. O compósito de PET reciclado/fibras de sisal, contendo em sua composição somente o plasticizante TBC, também apresentou um bom desempenho frente aos demais compósitos, com o melhor resultado de resistência à flexão, maior módulo de armazenamento e baixo teor de água absorvida. Assim, como pretendido, viabilizou-se o preparo de compósitos de PET reciclado/fibras de sisal, com a adição de diferentes tipos e misturas de plasticizantes, avaliando-se não somente a influência destes, assim como parâmetros de processo, uso de diferentes tipos de processamento e propriedades finais dos materiais gerados. / There is an increasing interest and need for the replacement of materials prepared from raw material obtained from fossil sources by those from renewable sources, such as polymeric composites reinforced with natural fibers. Additionally, the generation of plastic packaging disposal is accelerated in the country compared to materials recycling. In this context, the focus of this investigation was on the search for developing processes for the preparation of composites based on recycled poly (ethylene terephthalate) (recycled PET) and sisal fibers. The sisal fibers were characterized according to the content of major chemical components by X-ray diffraction, scanning electron microscopy (SEM), thermal analysis (differential scanning calorimetry (DSC) and thermogravimetry (TG)) and by infrared spectroscopy (IR). The recycled PET was characterized by DSC, TG, IV and melt index determination. Initially, composites of recycled PET/sisal fibers were processed in a Haake torque rheometer with subsequent thermopressing, at 260ºC, but this method proved to be inefficient, since fiber decomposition was observed, i.e., the decomposition of the fibers was not delayed by the matrix coating. Consequently, by aiming at obtaining a decrease of the melting temperature of the recycled PET (~ 265ºC) in order to avoid thermal decomposition of the fibers during processing, the plasticizers, acetyl tributyl citrate (ATBC), tributyl citrate (TBC), glycerol, castor oil (CO) and epoxidized soybean oil (OSE) were added to the formulations of the composites. In addition, hydroxylated liquid polybutadiene (PBHL) was added to the formulation of the material to evaluate its action as a compatibilizer/coupling agent in the fiber-matrix interface. It is emphasized that these plasticizers were chosen because they come from renewable sources, as well as having groups in the respective structures with affinity for both groups present in components of the fiber and the matrix. Thus the possible action of plasticizers as compatibilizers was also considered. The plasticizers were characterized by DSC, TG and IV. The exploitation of processing parameters using plasticizers was made by mixing the components using shovels, followed by compression molding. The composition of the mixture and the processing parameters, which led to the best set of results, were considered for processing via torque rheometry/thermopressing. The composites were characterized by SEM, DSC, TG, water absorption, and regarding their mechanical properties, by dynamic mechanical thermal analysis (DMTA) and impact and flexural strength. Analyzing the results, it is observed that when it comes to different processes of composites, compression molding was the most suitable for the preparation of the composites of recycled PET/sisal fibers, especially in relation to the superior mechanical performance presented by these materials compared to composites processed by torque rheometry and subsequent thermopressing. The non-reinforced recycled PET, among the mechanical properties shown, did not show a good impact strength, nor did the composites prepared from it, i.e., the property of recycled PET in the composites was predominant. However, not only did the use of plasticizers allow the processing of the composites at a lower temperature, but also it increased the wettability of the polymer-fiber by reducing the viscosity of the mixture. Still, in general, the SEM images of fractured surfaces of the composites showed a good adhesion between fiber-matrices, indicating activity of plasticizers and also compatibilizers between fiber and matrix. It is noteworthy that, in general, the results of flexural strength and DMTA pointed out that the presence of plasticizers led to less rigid and more flexible materials. Among the composites, it can be assumed that the mixture recycled PET/sisal fibers/glycerol/TBC presented the best mechanical performance, which in general led to the best result of impact strength, good flexural strength and fracture strain. The composite of recycled PET/sisal fibers in its composition, containing only the TBC plasticizer, also performed well compared to other composites, with the best result of flexural strength, higher storage modulus and low moisture absorption. Thus, as desired, the preparation of composites based on recycled PET/sisal fibers with the addition of different types and mixtures of plasticizers was enabled, evaluating not only their influence but also process parameters, the use of different types of processing and the final properties of the generated materials.

A caracterização dielétrica de um material pode ser usada como uma técnica não destrutiva para avaliar e monitorar sua qualidade, bem como no entendimento da relação estrutura-propriedade de um material, através de suas propriedades dielétricas em função da frequência, temperatura, composição química do material, dentre outros. Na literatura há escassez de trabalhos e dados de caracterização dielétrica de filmes a base de biopolímeros. Diante desse contexto, o objetivo deste trabalho foi o desenvolvimento e a construção de uma instrumentação alternativa a equipamentos disponíveis no mercado, como analisadores de rede e de impedância, que pudesse ser utilizada para a caracterização dielétrica de filmes biodegradáveis a base de gelatina. Foi utilizado o método de placas paralelas na determinação da parte real da permissividade conhecida como permissividade relativa ou constante dielétrica (&epsilon;\'). O circuito utilizado para a instrumentação foi um oscilador astável com funcionamento baseado no amplificador operacional (741) chaveado pela carga de um capacitor de placas paralelas cujo dielétrico foi uma amostra de filme biodegradável. A partir dos valores da frequência de oscilação e geometria do capacitor, foi possível calcular a capacitância de cada amostra e, consequentemente obter os valores da permissividade relativa do filme, usando relações básicas bem estabelecidas. Os filmes de gelatina foram produzidos pela técnica de casting sendo utilizados como plastificantes o glicerol (G), o sorbitol (S) e suas misturas, na proporção (G:S) de 30:70, 50:50 e 70:30. Os filmes foram caracterizados quanto à umidade e cristalinidade. A permissividade relativa (&epsilon;\') dos filmes, determinada a temperatura ambiente, foi avaliada em função da frequência (5 a 50 kHz), tempo de armazenamento, do teor de umidade e tipo de plastificante. A instrumentação projetada e construída foi capaz de medir com precisão a permissividade relativa das amostras, sendo que essa propriedade diminuiu com o aumento da frequência para todos os filmes. Mantendo-se a frequência constante, não houve variação de &epsilon;\' para os filmes de gelatina, independente do plastificante, ao longo de um mês de armazenamento a 24 ± 3 °C. O efeito da umidade foi observado em frequências menores que 25 kHz, sendo que quanto maior o teor de umidade maior a permissividade relativa. O efeito do tipo de plastificante na permissividade relativa dos filmes foi observado a baixas frequências (5 kHz) e filmes plastificados com sorbitol apresentaram maiores valores de &epsilon;\'. Os filmes plastificados com maior teor de umidade apresentaram menor cristalinidade, portanto maior mobilidade molecular e consequentemente maior a permissividade relativa. / The dielectric characteristics of a material can be used as a non-destructive technique to evaluate and monitor the quality as well as the understanding of the structure-property of a material, through its dielectric properties as a function of frequency, temperature, chemical composition of the material, among others. In the literature there are few studies and data of dielectric characterization of films based on biopolymers. In this context, the objective of this research was the development and construction of an alternative instrumentation equipment on the market, such as network and impedance analyzers, which could be used for the dielectric characterization of biodegradable films based on gelatin. The method of parallel plates was used to determine the real part of permittivity known as relative permittivity or dielectric constant (&epsilon;\'). The circuit used for the instrumentation was an astable oscillator operation based on operational amplifier (741) switched by the load of a parallel plate capacitor whose dielectric was a sample of the biodegradable film. From the values of the oscillation frequency and geometry of the capacitor, it was possible to calculate the capacitance of each sample and thus obtaining values of the relative permittivity of the film, using well established basic relationships. Gelatin films were produced by casting technique being used as plasticizer glycerol (G), sorbitol (S) and mixtures thereof, in proportion (G:S) 30:70, 50:50 and 70:30. The films were characterized for moisture and crystallinity. The relative permittivity (&epsilon;\') of the films, determined at room temperature, was evaluated as a function of frequency (5-50 kHz), storage time, moisture content and type of plasticizer. The designed and constructed instrumentation was able to accurately measure the relative permittivity of the samples, being that this property decreased with increasing frequency for all films. Keeping constant frequency, there was no variation in &epsilon;\' for the gelatin films, independent of the plasticizer over one month of storage at 24 ± 3 °C. The moisture effect was observed at frequencies lower than 25 kHz, how bigger the moisture content the higher the relative permittivity. The effect of the plasticizer type in relative permittivity of the films were observed at low frequency (5 kHz) and plasticized films with sorbitol have higher &epsilon;\' values. The plasticized films with higher moisture content exhibit lower crystallinity, hence larger molecular mobility and consequently higher the relative permittivity.