Plastproduktionen har ökat kraftigt i världen sedan 1950-talet, därmed även förekomsten av plastavfall som ansamlas i naturen. Det pågår flera initiativ på internationell nivå för att förebygga och hantera förekomsten av mikroplast i haven och en viktig aspekt för att minska miljöpåverkan från plastavfall är att öka användandet av bionedbrytbara material. Ett flertal analystekniker är tillgängliga i syfte att analysera nedbrytbarheten hos plaster men då metoderna är många och ibland överlappar har flera studier uppmärksammat behovet av harmonisering och standardisering. Syftet med denna studie var att undersöka bionedbrytning och mikroplastbildning av fyra material; lågdensitet polyeten (LDPE), poly (butylene adipate co-terephthalate) (PBAT), cellulosaacetat och papper. Materialen exponerades i kranvatten, sjövatten och havsvatten med exponeringstid 2 respektive 5 veckor. Materialen analyserades därefter med FTIR, DSC, dragprov och vägning. Konduktivitet och pH kontrollerades på mediet. Valda analystekniker jämfördes med syfte att iaktta dess lämplighet utifrån material och medie. Aspekter som analyserades och diskuterades var nedbrytning utifrån molekylär struktur, utifrån omgivande faktorer samt utifrån nedbrytningens tre faser. Studien visade att cellulosaacetat brutits ned mest under perioden, därefter PBAT. LDPE och papper hade inte brutits ned nämnvärt. Den analysteknik som främst visade på skillnader i nedbrytning var vägning. Resultatet indikerade även att analysteknikernas lämplighet varierade med material samt skede av nedbrytningsprocessen. Vägning, pH-mätning och dragprov var de metoder som tillförde mest i den tidiga fasen av nedbrytningsprocessen. Den skillnad som medierna förväntades utgöra för nedbrytningsprocessen var svår att utläsa baserat på genomförda analyser. / The production of plastics has increased significantly worldwide since the 1950s and a consequence of this is an increase of plastic waste in nature. A number of initiatives are ongoing internationally to prevent and handle the presence of micro plastic in oceans and an increase of biodegradable materials is one important aspect in order to reduce the environmental impact from plastic waste. Today, many techniques are available in order to analyze degradability of plastics. However, they sometimes overlap and a need for standardization and harmonization has been recognized. The purpose of this study was to investigate biodegradability and micro plastic formation inaquatic environments. Low density polyethylene (LDPE), poly (butylene adipate coterephthalate)(PBAT), cellulose acetate and paper have been evaluated. The medium for exposure has been tap water, fresh water and sea water with exposure time of 2 and 5 weeks.The material was analyzed with FTIR, DSC, tensile testing and weight measurement. Additionally, conductivity and pH was measured on the medium. The analytical techniques were evaluated in order to observe their suitability for different material and medium. Aspects that have been discussed and analyzed throughout this paper are degradability based on molecular structure, surrounding factors affecting degradability and the three phases of degradability. The results of this study showed that cellulose acetate degraded the most, thereafter PBAT. LDPE and paper did not indicate any noticeable degradation. Weight measurement gave the clearest indication of degradation. Together with pH measurement and tensile testing; these were the analytical techniques that added the most in the early phase of degradation. Furthermore, the results showed that the suitability of an analytical technique varied with both material and phase of degradation. Additionally, the effect that was expected to be observed based on the different medium was not noticeable within this exposure time.

En este trabajo se ha evaluado la viabilidad de la utilización de reactores convencionales de craqueo catalítico en lecho fluidizado (FCC) para el reciclado de los plásticos presentes en los residuos sólidos urbanos. Se ha diseñado y puesto a punto una unidad de FCC a escala de planta piloto, con un reactor tipo “riser” operando en condiciones similares a las que se encuentran en las instalaciones comerciales de FCC. La unidad construida permite el craqueo, separación y recogida de los productos sólidos, líquidos y gaseosos generados en los ensayos llevados a cabo. El diseño de la planta involucra, entre otros aspectos, el diseño y construcción del reactor de craqueo catalítico fluidizado por arrastre de sólidos y de las conducciones entre el reactor y los equipos de separación; el diseño y construcción del sistema para la recogida de las diferentes fracciones de productos; el diseño, construcción e instalación de los instrumentos de medida y control necesarios, y el estudio y optimización de las condiciones de operación y fluidodinámica de la planta (temperatura del reactor, velocidad de fluidización y arrastre, caudal de alimentación, etc.). Se ha estudiado el comportamiento reológico de las mezclas de residuo de vacío y plásticos, determinando la influencia de la composición y la temperatura sobre su comportamiento reológico, lo que ha permitido analizar la problemática de introducción del residuo plástico en este tipo de reactores de FCC. Se ha estudiado en profundidad el sistema gasóleo+PE (10%)+catalizador FCC como alimento de la unidad construida, trabajando con distintas relaciones catalizador/alimento (5:1, 7:1, 10:1) a distintas temperaturas (500, 600 y 700ºC). Se ha analizado la influencia de las condiciones de operación sobre los productos de pirólisis, centrándose en la búsqueda de sistemas que favorecen la obtención de productos con valor como combustible (dentro del rango de las gasolinas) y de gases ricos en olefinas que puedan ser utilizadas como materias primas en distintos procesos. Finalmente, se han estudiado diferentes sistemas gasóleo+polímero (EVA y PP)+catalizador (HZSM-5, HBeta) para comprobar la versatilidad y las limitaciones de la planta. El resultado del estudio llevado a cabo pone de manifiesto la viabilidad del reciclado de residuos poliméricos en las unidades de FCC de las instalaciones comerciales, convirtiendo dichos residuos en combustibles y compuestos petroquímicos de interés.

The main intention of this thesis work was to investigate the effect of strain rate on continuum and pre-cracked polymer failure. Low-Density Polyethylene (LDPE) was chosen to study experimentally and numerically. In order to cover wide range of strain rates, four specific strain rates were selected for the uniaxial tensile tests. To perform the tests, cyclic loading and unloading with relaxation was utilized in the room temperature for continuum specimen and for pre-cracked specimen monotonic tensile test till failure was utilized. Through Digital Image Correlation (DIC) the local strain distribution was assessed through the specimen and the deformation was compared with simulation results. Based on the extensive literature review of material models from PolyUMod library among Viscoplastic models, the Three Network Viscoplastic (TNV) model was selected to proceed with the calibration. The motivation behind choosing TNV model is it's capability of capturing load-unload curves, different strain rates as well as non-linear responses. Furthermore, it was seen that among Viscoplastic models, TNV has the lowest average errors which plays a vital role in this case as the accuracy of FE simulation directly depends on the calibration results. From the experimental results it was safe to say that with increasing strain rates LDPE films tend to get stiffer and stronger both in continuum and pre-cracked. Through the calibration it was seen that the predicted curves were in reasonable agreement with experimental ones. Hence,the calibrated model was exported as python script into Abaqus CAE to perform the simulations. The comparison was done and discussed in details between the simulation and experimental data in three orientations; MD (Machine Direction), CD (Cross Direction) and 45 direction.

Microplastic (MP) pollution has recently been recognized as a threat to the biosphere including humans due to its widespread distribution, persistent nature and infinitesimal size. This study focused on the solid phase degradation of microplastic residues (particularly low density polyethylene, LDPE) in water through heterogeneous photocatalysis process by designed photocatalysts of zinc oxide nanorods (ZnO NRs) and platinum nanoparticles deposited on zincoxide nanorods (Pt NPs-ZnO NRs) under visible light irradiation. These photocatalysts were assessed following standard protocol (ISP 10678: 2010), and characterized using SEM, EDX andoptical spectroscopies (UV-VIS and PL). Deposition of Pt-NPs on ZnO NRs for certain minutes has been found optimum that enhanced the photodegradation process about 38% under UV irradiation and 16.5% under visible light irradiation by improving of both electrons-holes pair separation process and visible light absorption. Photocatalytic degradation of LDPE films was confirmed by FTIR spectroscopy, dynamic mechanical analyzer (DMA), optical and electron microscopes. When LDPE film irradiated in presence of Pt-ZnO, degradation was found quicker than ZnO alone of similar concentration which exhibited formation of a large number of wrinkles, cracks and cavities on the film surface. Dynamic mechanical analyzer (DMA) test indicated stiffness and embrittlement of exposed LDPE films in presence of photocatalysts. Thus, the present work provides a new insight about modified catalysts for the degradation of microplastics in water using visible light.

La DCE a pour principale ambition d’harmoniser les politiques de l’eau sur un plan européen et d’atteindre le bon état des eaux d’ici 2015. L’évaluation de ce “bon état” implique en outre de dresser l’inventaire, dans les masses d’eau, des 33 substances prioritaires listées en annexe X de la DCE (annexe X, décision No 2455/2001/EC) et pour lesquelles des normes de qualité environnementales (NQE) ont été fixées (Directive 2013/39/EU). Parmi ces substances figurent les polychloroalcanes (SCCPs) et les polybromodiphényléthers (PBDEs) appartenant à la catégorie des micropolluants halogénés “émergents”. D’un point de vue analytique, leur détermination dans l’eau constitue actuellement un enjeu majeur, tant sur le plan de l’échantillonnage que de la sensibilité.Dans ce contexte, ce travail de thèse s’est attaché au développement d’une méthode d’analyse des SCCPs dans les eaux par SPME couplée à la GC/ECNI-MS. Les limites de quantification inférieures à 0,2 µg.L-1 et son degré d’automatisation font de cette méthode un outil de choix pour assurer le monitoring des milieux aquatiques tels que requis par la DCE. En complément de l’approche classique, un pilote de calibration en laboratoire pour l’étalonnage d’échantillonneurs passifs a pu être mis en place et validé pour la calibration des MESCO avec les HAPs. La participation à un essai interlaboratoire a permis de tester l’applicabilité des MESCO et des SR pour l’analyse des PBDEs en sortie de station d’épuration. Enfin la mise en application des LDPE, SR et MESCO sur l’étang de Berre a permis d’obtenir des résultats encourageants quant à l’applicabilité de ces échantillonneurs passifs pour l’analyse des SCCPs et PBDEs. / In order to achieve good water quality for 2015, the water framework directives (WFD 2000/60/EC and 2013/39/EU) force European countries to monitor the quality of their aquatic environment. For this purpose, all water bodies shall be monitored for all the 33 priority substances listed in annex X of WFD (annex X, decision No 2455/2001/EC) and for which environmental quality standards (EQS) were fixed (Directive 2013/39 / EU). Among these substances, we found the short chain chlorinated paraffins (SCCPs) and the polybrominated diphenyl ethers (PBDEs) belonging to the class of emergent halogenated micro-pollutants. From an analytical point of view, the analysis of SCCPs and PBDEs in water is still a major challenge, either in terms of sampling or sensitivity.In respect of WFD, this thesis work has, among other things, aimed to develop a method to analyze SCCPs in water by using SPME coupled with GC/ECNI-MS. The limit of quantification below 0.2 µg.L-1 and its degree of automation makes this method a tool of choice to ensure the monitoring of the aquatic environment as required by the WFD. In addition to the traditional approach, a laboratory system for passive sampler calibration was also developed and validated to calibrate MESCO for PAHs analysis. Moreover, our participation in an inter-laboratory study, has served to test the applicability of MESCO and SR for the analysis of PBDEs in a waste water treatment plant. Finally the deployment of LDPE, SR and MESCO in Berre lagoon has yielded some encouraging results about applicability of these passive samplers to analyze SCCPs and PBDE in water.

Made available in DSpace on 2017-07-21T20:42:34Z (GMT). No. of bitstreams: 1 Armando Madalosso Vieira Filho.pdf: 12599724 bytes, checksum: 65d627ecd808a90acce0c965752d8655 (MD5) Previous issue date: 2009-09-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Finding new ways and techniques of recycling has been one of the main paths searched by investigators to solve the problem of the garbage. For this study were chosen two of the polymers with large volumes of post-consumer material: LDPE and rubber tire. Several studies have been made to incorporate rubber tire in polymers by following different paths one of them is the devulcanization of rubber tire by microwave. The focus of this study was process and characterize blends of virgin and / or recycled LDPE with ground tire rubber. Both formulations, virgin and recycled LDPE, were made with percentage by weight of 0, 5, 10, 20 and 40 of rubber in and with percentage by weight of 0 and 10 in the blends of 50% virgin / 50% recycled LDPE. The formulations were processed into a of single screw extruder, granulated, injected and treated with microwave “in situ”. Tests were made for size distribution of the rubber, tensile, bending, optical and scanning electron microscopy, DSC and infrared spectroscopy. As results obtained were: a rubber tire can be used as an additive for staining, mechanical properties similar to almost all formulations was obtained with up to 10% of tire rubber. The amount of rubber incorporated and composition (recycled or virgin) influence the mechanical and thermal properties of some blends. The treatment with microwaves "in situ" presented influence on the mechanical and thermal properties in the formulations tested, presenting differential properties, such as increased maximum stress in some formulations, demonstrating that the study of the treatment is technologically interesting. / Encontrar novos meios e técnicas de reciclagem têm sido um dos grandes caminhos buscados por pesquisadores para resolver o problema do lixo. Para este estudo foram escolhidos dois dos polímeros com grandes volumes de material pós-consumo: PEBD e borracha de pneu. Várias pesquisas têm sido feitas no sentido de incorporar borracha de pneu em polímeros seguindo diversos caminhos e dentre eles está a desvulcanização da borracha por microondas. O objetivo deste trabalho foi processar e caracterizar misturas de PEBD virgem e/ou recicladas incorporadas com pó de borracha de pneu. Foram feitas formulações com teores de 0, 5, 10, 20 e 40% em peso de borracha no PEBD virgem e reciclado, e 0 e 10% em blendas de PEBD/ PEBD reciclado (50/50). As formulações foram processadas em extrusora de rosca simples, injetadas e tratadas com microondas “in situ”. Foram feitos ensaios de distribuição granulométrica da borracha, tração, flexão, microscopia, DSC e FTIR. Observou-se: que a borracha de pneu pode servir como aditivo para fins de coloração; propriedades mecânicas similares com até 10% de borracha para quase todas as formulações; que a quantidade de borracha incorporada e o tipo de matriz influenciam as propriedades mecânicas e térmicas. O tratamento “in situ” com microondas apresentou influência nas propriedades mecânicas e térmicas nas formulações ensaiadas apresentando propriedades diferenciadas, como aumento da tensão máxima em algumas formulações, demonstrando que o estudo do tratamento é interessante tecnologicamente.

Abstract This thesis correlates rheological data into a non-linear blown film model that describes the stress and cooling-induced morphological transformations in the axial and flow profiles of the blown films. This will help to improve the physical and mechanical properties of the films in a cost effective way, which will in turn be of great benefit to the food and packaging industries. In this research, experimental and numerical studies of a blown film extrusion were carried out using two different low-density polyethylenes (LDPEs). In the experiment, the key parameters measured and analysed were molecular, rheological and crystalline properties of the LDPEs. In the numerical study, blown film simulation was carried out to determine the bubble characteristics and freeze line height (FLH). A new rheological constitutive equation was developed by combining the Hookean model with the well known Phan-Thien and Tanner (PTT) model to permit a more accurate viscoelastic behaviour of the material. For experimental verification of the simulation results, resins were processed in a blown film extrusion pilot plant using identical die temperatures and cooling rates as used in the simulation study. Molecular characteristics of both LDPEs were compared in terms of their processing benefit in the film blowing process. Based on the experimental investigation, it was found that molecular weight and its distribution, degree of long chain branching and cooling rate play an important role on melt rheology, molecular orientation, blown film processability, film crystallinity and film properties. Effect of short chain branching was found insignificant for both LDPEs. Statistical analysis was carried out using MINITAB-14 software with a confidence level of 95% to determine the effect of process variables (such as die temperature and cooling rate) on the film properties. Film properties of the LDPEs were found to vary with their molecular properties and the process variables used. Blown film model performance based on the newly established PTT-Hookean model was compared with that based on the Kelvin model. Justification of the use of PTT-Hookean model is also reported here using two different material properties. From the simulation study, it has been found that predictions of the blown film characteristics conformed very well to the experimental data of this research and previous studies using different materials and different die geometries. Long chain branching has been found as the most prominent molecular parameter for both LDPEs affecting melt rheology and hence the processability. Die temperature and cooling rate have been observed to provide similar effect on the tear strength and shrinkage properties of blown film for both LDPEs. In comparison to the Kelvin model, the PTT-Hookean model is better suited for the modelling of the film blowing process. It has also been demonstrated in this study that the PTT-Hookean model conformed well to the experimental data near the freeze line height and is suitable for materials of lower melt elasticity and relaxation time.

Bimodal polyethylene resins are frequently used for pipe applications. In this work, blending was used to produce polyethylenes with comparable properties, particularly with respect to processing, stress crack resistance and tensile properties. Suitable blend components were identified, and their performance screened used ECHIP experimental design software. Blends were characterized using gel permeation chromatography (GPC), differential scanning calorimetry (DSC), tensile testing, stress crack resistance measurements, impact toughness testing, capillary rheometry and melt index measurements. GPC, DSC and melt index results reveal that the method of meltcompounding produced morphologically uniform blends, with different degrees of compatibility depending on the type and level of branching of blend components. Most of the blends produced showed higher crystallinity values compared to a reference bimodal resin. Binary high density polyethylene (HDPE) blends showed better stiffness and strength properties, whereas metallocene catalyzed linear low density polyethylene (mLLDPE) containing blends illustrated superior elongation and toughness properties compared to the reference polymer and other binary blends. The highest resistance to slow crack growth (SCG) was shown by low density polyethylene (LDPE) and mLLDPE containing blends due to their high branching content. The overall blend resistance to SCG or toughness can be enhanced with levels less than 20% by weight of LDPE or mLLDPE in the blend although the tensile properties are relatively unaffected at these low concentrations. The performance of blends was optimized by changing component polymers and their weight fractions, and a model to predict optimum blends was developed using the Maple code. Optimized blends showed higher branching content, comparable molecular weight, molecular weight distribution, tensile properties, viscosity and processing behaviour to the reference polymer. Optimized blend 3, in particular, encountered the same degree of shear thinning as the reference material. Better toughness and resistance to SCG were shown by the optimized blends when compared to the reference polymer.

In this study, the High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE) blends prepared by Plasticorder Brabender were strengthened by adding Carbon Black (CB). Blends were prepared at 190 &deg / C. Amounts of LDPE were changed to 30, 40, 50 and 60 percent by the volume and the percent amounts of CB were changed to 5, 10,15, 20 and 30 according to the total volume. Thermal and morphological properties were investigated by using Differential Scanning Calorimeter (DSC), Scanning Electron Microscope (SEM). Mechanical properties were investigated by tensile test and hardness measurements. Melt flow properties were studied by Melt Flow Index (MFI) measurements. Electrical conductivities were measured by four probe and two probe techniques. Temperature dependence of electrical conductivity was also studied. In general, it is observed that stress at break and MFI values decrease by the addition of CB / however, modulus and hardness increase. DSC results indicated that the crystallization of the polymer blend was decreased by the addition of CB. SEM results showed that the components were mixed homogenously. Increasing CB content increased electrical conductivity. Furthermore, by increasing the temperature, positive temperature coefficient behavior was observed which increases when CB content decreased.

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