A series of four novel halosilylsubstitued monocyclopentadienyl titanium complexes; [Si(CH3)2FCp]TiCl3 – FSiTTC, [Si(CH3)F2Cp]TiCl3 F2SiTTC, [Si(CH3)Cl2Cp]TiCl3 - Cl2SiTTC, [Si(CH3)2ClCp]TiCl3 - ClSiTTC was tested as catalytic precursors for polymerization of styrene in toluene. The maximum polymerization activity was achieved after polymerization period of 20 minutes. Activity decreased in order FSiTTC/MAO > F2SiTTC/MAO > Cl2SiTTC/MAO > ClSiTTC /MAO. Prepared polystyrenes were characterized using 13C NMR spectroscopy and DSC analysis. Syndiotacticity index of obtained PSs was determined by means of Soxhlet extraction with butan-2-one as solvent. Syndiotacticity indexes of PSs obtained by investigated catalysts possessed higher values then those obtained by standard catalysts (CpTiCl3 a Cp*TiCl3) at comparable polymerization conditions.

This thesis deals with the cutting of flat shapes of polystyrene by industrial robot using Robotmaster. There are some variants of the shaped components that can create by using Robotmaster. The task of the work is also a demonstration task in the realization of use a resistance wire as a tool and polystyrene boards as a workpiece material.

Nowadays, there is an increasing risk of bacterial infections from bacteria strains resistant towards antibiotics. Thus, it is of utmost importance to research novel therapies which can overcome this difficulty. The presented thesis focuses on the preparation, characterization and antibacterial evaluation of polystyrene polymer nanomaterials (nanofiber membranes and nanoparticles) modified with compounds that can efficiently inhibit bacterial growth either by their nature (polyethyleneimine) or by photoactivation upon visible light excitation (NO- photodonors, photosensitizers) and consequent production of highly reactive inorganic bactericidal species, nitric oxide (NO) and singlet oxygen (O2(1 g)). All materials were fully characterized by several independent methods. The concentrations of NO and O2(1 g) were measured by amperometric and time-resolved spectroscopic techniques and by variety of chemical analytic procedures. Due to the presence of bactericidal species and the efficient photogeneration of NO and O2(1 g) at physiological conditions, all materials exhibit strong antibacterial action tested on a Gram-negative bacterial strain Escherichia coli. Hence, these functionalized polymer nanomaterials may be intriguing systems for medical-, biological-, or environmental- application where a...

Certain models of NIOSH-approved filtering facepiece air purifying respirators are manufactured with stapled head straps. Depending on the manufacturer, these head straps may be stapled to the filter media itself. This may cause leakage through the filter media of the respirator, potentially exposing the user to an unacceptable level of contaminant. In this study, monodisperse polystyrene latex (PSL) spheres were generated to challenge four replicates of a N95 single use respirator model made by the same manufacturer. Nominal particle sizes of the PSL spheres used to challenge the respirators were 0.5, 1, and 2 micrometers in diameter. All respirators were sealed onto a custom built testing assembly and tested in a sealed chamber. Particle sizes of interest were generated using a nebulizer, and passed through a diffusion dryer and a Krypton-85 radioactive source prior to entering the test chamber. The dryer reduces the humidity of the aerosol generating by the nebulizer, while the radioactive source neutralizes the charge of the aerosol cloud. The test chamber was constructed using a glass aquarium measuring 32 x 53 x 122 centimeters. Three stainless steel air diffusers were placed above the testing compartment to evenly distribute the aerosol in the chamber. An exhaust manifold was placed at the lower part of the chamber beneath another stainless steel diffuser below the area where test respirators were placed. The respirators were challenged as received from the manufacturer with 0.5, 1 and 2 micrometer-sized (PSL) spheres. The same procedure was repeated for each respirator after sealing the areas where the head straps were stapled with silicon rubber. Testing was conducted at a flow rate of 85 liters per minute, as specified in the NIOSH respirator testing protocol. A laser particle counter was used to measure the concentration inside and outside of the respirator. The results showed unsealed efficiencies for particle sizes 0.5, 1, and 2 micrometers of 96.68%, 99.72%, 99.88% and sealed efficiencies of 97.35%, 99.82%, 99.93% respectively. There were no differences for particle size or sealing at 1.0 and 2.0 micrometers. A significant drop in efficiency was observed when testing with 0.5 micrometer PSL spheres. The drops in efficiency are not sufficient to reduce the integrity of the respirator for N95 certification. However, the leakages detected will have a cumulative effect when added to other sources of single use respirator leakage in the field.

Surgical masks are intended to be used to prevent transmission of disease from a health care worker to a patient. Often times, they are relied upon by health care workers for their own protection. In light of recent developments regarding preparation for health care worker response to global infectious diseases such as H1N1 Influenza, health care workers may experience a false sense of security when wearing surgical masks. The goal of this study was to evaluate the filtration efficiency of a double strap tie-on surgical mask. The manufacturer asserts a >95% efficiency with a 0.1 um challenge aerosol under FDA testing procedures. The NIOSH Title 42 CFR Part 84 certification criteria call for testing at a rate of 85 lpm representing a human moderate to heavy work load breathing rate. Three sizes of monodispersed aerosols (polystyrene latex beads: 0.5 um, 1.0 um, 2.0 um) were used. The specific aims were to measure the collection efficiencies of this mask for the various particle sizes. Two tests were performed. In the first, masks were affixed to a dummy head and the edges of the mask were not sealed. In the second, the edges of the masks were sealed to the head using silicone sealant, so all penetration was through the filtering material of the mask. Differences in upstream and downstream particle concentrations were measured. Thus, penetration by leakage around the mask and through the filtering material was measured. The experimental set up involved passing the aerosol from the nebulizer through a diffusion dryer and Kr-85 charge equilibrator ensuring a dry charge neutralized aerosol cloud for detection by a LASAIR particle counter. The analysis revealed that the filtration efficiency for 0.5 um particles ranged from 3% to 43% for the unsealed masks and 42% to 51% for the sealed. For 1.0 um particles, the efficiency was 58% to 75% for unsealed and 71% to 84% for sealed masks. For 2.0 um, the efficiency was 58% to 79% for unsealed masks and 69% to 85% for the sealed masks. The data were statistically significant and indicated that surgical masks were associated with very low filtration efficiency. This suggests that they may be inadequate against airborne viruses and bacteria.

In this research three waste scenario’s for polystyrene plastic are analysed and compared from an environmental perspective. Incineration, recycling and biodegradation by mealworms (Tenebrio Monitor Linnaeus) of polystyrene are to be compared through a gate to grave Life Cycle Analysis. This LCA is conducted through the International Standard Organisation, 14040 Standard. The biodegradation facility is non existing and based on assumption backed up by peer reviewed literature. Incineration and recycling are based on facts and figures from national authorities and supplemented and peer reviewed literature. All three processes are analysed using IPCC Global Warming Potential (GWP) 2013 GWP 100a &amp; 1.03 ReCipe 2016 Midpoint (H) 1.02 within SimaPro 9. Results show that the biodegradation of polystyrene by mealworms is inferior to the two already existing methods of recycling and incineration from an environmental perspective. The environmental preference of recycling or incineration cannot be clearly defined. From an energy perspective (GWP) recycling is highly preferred over incineration. From ReCiPe 2016 methods incineration is highly favourable compared to most impact categories. However results are not likely to represent realistic values valid today due to lack of (accurate) data within this LCA. It is unlikely that without supplemented data results from this research can be used in any form. Nevertheless this lack of information shows the need for further investigation on biodegradation by mealworms. / <p>2020-06-05</p>

The diploma thesis is dedicated to the exploitation of sulphonated polystyrene nanofibres as ion exchange nanomaterial. Ion exchange capacity of these nanomaterials has been determined by titration method and AAS. The effect of sulphonation on photophysical, photooxidative and photocytotoxic properties of sensitizer 5,10,15,20-meso- tetraphenylporphyrin (TPP) encapsulated in polystyrene nanofibres has been studied as well. Properties of TPP have been examined with time-resolved spectroscopy, photooxidation of uric acid as substrate and bactericidal tests on Escherichia coli DH5α with pGEM11Z plasmid. It has been discovered that following the sulphonation of the nanofabrics, the encapsulated sensitizer is partly present even in aggregation form. The polystyrene nanofabrics with encapsulated sensitizer keep its bactericidal efficiency also after sulphonation.

Polymeric isoporous membranes have many interesting properties leading to various specific applications in different fields. However, such structures also have one main drawback, namely their poor solvent stability, which should be improved to extend the range of their possible applications. Therefore, this project will focus on the enhancement of solvent stability of polymeric isoporous membranes by UV cross-linking. Stable isoporous films were obtained by creating honeycomb membranes from star polystyrene (PS) and its derivatives. The star PS was synthesized by Atom Transfer Radical Polymerization (ATRP) method and was then functionalized with methacrylate groups. The isoporous films made from these materials maintained the honeycomb structures after curing by UV light and immersion in chloroform. The crosslinking of PS under UV light exposure rather than the cross-linking of the methacrylates groups was responsible for the solvent stability of these membranes. To further investigate the effect of specific end-groups on the film stability, PEG2k-G3-PCL30 linear-dendritic-linear hybrid polymers and its derivatives with allyl, acrylate, methacrylate end-groups were employed to cast films. Functionalized PEG2k-G3-PCL30 linear-dendritic-linear hybrid isoporous films were cross-linked by UV-induced thiol-ene reactions and allyl reactions. However, no significant increase in the solvent stability of these kinds of films was observed. When mixing PEG2k-G3-PCL30 linear-dendritic-linear hybrids with star PS, stable isoporous films could be obtained. The pores became smaller but the isoporous structures were still kept.

En la siguiente tesis se presenta los resultados de un trabajo de investigación sobre los deficientes procesos autoconstructivos de las estructuras de una vivienda de dos pisos en el Asentamiento Humano Vivienda Única - San Juan de Miraflores. Sabemos que un gran porcentaje de la población habita en viviendas autoconstruidas, vulnerables a cualquier fenómeno de la naturaleza, pues no cumplen con los parámetros de construcción establecidos. Para desarrollar el problema y los objetivos de la presente tesis de investigación se resume a continuación el contenido de cada capítulo a desarrollar. Primero se identifican los principales factores internos y/o externos que motivaron a los pobladores en la autoconstrucción de sus viviendas, mediante una encuesta en campo realizada a 30 pobladores del Asentamiento Humano Vivienda Única. Luego se procesaron los datos obtenidos y se graficaron los resultados. Seguido, se determinó las condiciones de estas viviendas y se detalló cuáles son los daños que pueden afectar negativamente su comportamiento ante un eventual sismo. Para conseguir la información requerida se realizó una evaluación de 5 viviendas donde se recabaron los datos necesarios con ayuda de los pobladores y el presidente de la zona en mención. Después de realizar esta investigación se pasó a formar la guía de autoconstrucción para mejorar los procesos constructivos deficientes donde se encontrará los materiales y procedimientos óptimos para la construcción de una vivienda en el Asentamiento Humano Vivienda Única. Por último, se diseñará un modelo de vivienda de dos pisos de un área de 120 m2 donde se realizará el diseño de los principales elementos estructurales, y se realizará un análisis costo - beneficio entre dos sistemas de losas: el sistema convencional y el sistema con viguetas pretensadas y casetones de poliestireno. / The following thesis presents the results of a research work on the deficient self-constructive processes of the structures of a two-story house in the Single House Human Settlement - San Juan de Miraflores. We know that a large percentage of the population lives in self-built houses, vulnerable to any phenomenon of nature, as they do not meet the established construction parameters. To develop the problem and the objectives of this research thesis, the content of each chapter to be developed is summarized below. First, the main internal and / or external factors that motivated residents to self-build their homes are identified through a field survey of 30 residents of the Single House Human Settlement. Then the obtained data were processed and the results were plotted. Next, the conditions of these homes were determined and the damages that could negatively affect their behavior in the event of an eventual earthquake were detailed. In order to obtain the required information, an evaluation of 5 houses was carried out, where the necessary data was collected with the help of the residents and the president of the area in question. After carrying out this research, the self-construction guide was formed to improve the deficient construction processes where the optimal materials and procedures for the construction of a house will be found in the Single House Human Settlement. Finally, a two-story house model of an area of 120 m2 will be designed where the design of the main structural elements will be carried out, and a cost-benefit analysis will be carried out between two slab systems: the conventional system and the system with prestressed joists and polystyrene shells. / Tesis

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