Barrier Properties of Filled High-impact Polystyrene

Tato práce je zaměřena na hodnocení vlivu různých druhů plniv o různých koncentracích v hPS na bariérové a mechanické vlastnosti. Cílem je srovnat vliv různých druhů (nano)plniv na propustnost pro plyny a vodní páru. Úroveň rozmíchání nanoplniva v polymerní matrici bylo stanoveno pomocí RTG analýzya TEM. Získané výsledky naznačují, že zde existuje korelace mezi velikostí částic nanoplniva a konečnými vlastnostmi. Některé vzorky vykázaly zlepšení bariérových vlastností.This work is focused on the evaluation of the effect of different kinds of fillers with various concentrations in high impact polystyrene on barrier properties, hardness and resilience. The aim is doing comparison of the effect of different kinds of fillers and nanofillers on gas and water permeability. Dispersion of nanofiller in polymer matrix was determined by X-ray diffraction and transmission electron microscopy. Gathered results indicate that there is a correlation between the size of the filler particles and final compound properties. Some samples showed an improvement of barrier propertie

The Mechanical and Optical Properties of the PVB Nanocomposites with Modified Nanofiller

Poly(vinyl butyral) (PVB) is an industrially important polymer used in laminated safety glass for its very high adhesion to glass and excellent optical properties. Clay nanofillers ? clays have been frequently used in recent research. In the case of PVB, there is a possibility to deteriorate its good optical and adhesive properties. Therefore this study is focused on evaluation of optical properties of PVB nanocomposites. These were prepared by kneading in Brabender, matrix was plasticized PVB with modified nanoclay montmorillonite as fillers, namely Cloisite Na+. The nanoclay was modified by a grafting methodthree different types of intercalation agents were used for the modification, 3-minopropyltriethoxysilane (APS), trimethylchlorosilane (TMCS) and octyltrimethoxysilane (OTMS). The modification of nanoclay was done in the proportion of nanoclay to silanes - 1:0.3. The samples were compared with pure PVB and nanocomposites with commercially modified montmorillonite, Cloisite 30B. Films of the composites were prepared by hot press molding. All nanocomposite samples had loading 0.5, 1, 2 and 3 of nanoclay. The materials were characterized by X-ray diffraction (XRD), optical microscope, tensile test and spectrophotometer. XRD determined that PVB nanocomposites reached intercalated/exfoliated structure. The Break stress of PVB nanocomposites was increased for most nanofillers. The light transmission of the PVB nanocomposites was analyzed by spectrophotometer. The data showed that the light transmission decreases with increasing loading level of nanoclay and the light transmission was significantly different for every nanofiller

Description of degradation influence on the plasticized PVB during its re-working by kneading

PVB sheet (type Butacite 3GO) with polymer chains containing butyraldehyde, hydroxyl- and small amount of acetate groups, was tested. These sheets were highly plasticized, with the content of plasticizer 28%. Studied material was tested at different kneading conditions; especially the influence of temperature, oxygen, mechanical energy and created heat of dissipation was studied. PVB sheet was kneaded at their usual humidity oca 0.5%. Because PVB in known as the material with high hydroscopity, next tests were done on PVB sheets macerated in water. By this operation the humidity of sheets increases to the content 8.0%. High humidity influenced all observed properties. Simultaneously, samples of PVB sheets re-worked by calendaring and pressing. At the calendaring the sheets were thermally stressed. The calendaring represents shear stress at low temperature. The degradation was evaluated as the change of optical properties, like the light transmittance through the re-worked material, created haze and yellowing. Next evaluated data were the change of mechanical properties - melt flow index and stress-strain behaviour. Summarized data were used for the choice of the optimal conditons for re-working of PVB sheets. The optimal conditions should bring the lowest energetic costs, minimal shear and thermo-oxidative degradation

Degradation of plasticized PVB during reprocessing by kneading

V práci byly testovány možnosti optimálního přepracování PVB. Cílem práce bylo sledovat degradaci PVB folií za různých podmínek hnětení a odhadnout vliv teploty, vzdušného kyslíku a mechanického namáhání na vývoj degradace materiálu. Pro potvrzení vlivu vlhkosti na vlastnosti PVB během přepracování byly folie nasyceny vodou v 0,5 a 8%ní koncentraci. Degradační změny PVB byly hodnoceny ze změn ITT, mechanických vlastností, žlutosti a molekulové hmotnosti. Ze získaných výsledků byly navrženy optimální podmínky pro přepracování.Possibility and conditions for optimal re-processing of plasticized polyvinylbutyral (PVB) were tested. The aim of this work was to investigate degradation of PVB sheet at various kneading conditions and to estimate the influence of temperature, air oxygen and mechanical stress on the progress of degradation process. In order to confirm the influence of humidity on the PVB properties during reprocessing, the sheets with the humidity content Of 0.5 and 8.0% were tested. The PVB degradation was determined from the changes of melt flow index, mechanical properties in terms of stress and elongation at break, yellowness and molecular weight distribution. The optimal recycling conditions for PVB were estimated from the evaluation of all measured properties and their changes