1,899,472 research outputs found
Thermomechanical properties of ABS/PA AND ABS/PC blends
Get PDFThe significant increase of Waste Electric and Electronic Equipment (WEEE) has led to an important research in upgrading recycled engineering plastics by means of a blending technique. Classical twin-screw extrusion is compared to a new blending technique, where two polymers are combined together and then flow in several static mixers. This technique allows to obtain different morphologies of compatibilized ABS/PA or ABS/PC blends and the aim of this work is to evaluate the corresponding thermomechanical properties. Experimental results demonstrate in particular that fibrilar morphology is obtained with the new blending technique (only with ABS/PA blends), which could lead to a mechanical enhancement if the adhesion between ABS and PA is optimized
Modificação da superfície de peças em PVC e blendas PVC/ABS para adesão de camadas metálicas
Get PDFTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Química, Florianópolis, 2014.Visando a substituição do terpolímero ABS (acrilonitrila-butadieno-estireno) no processo de cromagem, neste trabalho, foi avaliada a modificação química da superfície de peças injetadas de PVC (policloreto de vinila) puro e blendas de PVC/ABS nas proporções de 20/80, 40/60 e 60/40. As peças foram previamente caracterizadas por ensaios térmicos e mecânicos, como termogravimetria (TGA), calorimetria exploratória diferencial (DSC) e ensaio de tração e submetidas ao pré-tratamento químico sob diferentes condições operacionais, variando-se os reagentes, concentração, temperatura e tempo de tratamento. Para avaliação da modificação ocasionada pelo pré-tratamento na superfície, as peças de PVC puro e das blendas foram analisadas por microscopia eletrônica de varredura (MEV), espectroscopia no infravermelho (FTIR/ATR), microscopia de força atômica (AFM), ângulo de contato e rugosidade. As amostras também foram cromadas e foi avaliada a qualidade da adesão das camadas metálicas, por inspeção visual, adesão e corrosão por névoa salina (salt spray) e os resultados foram comparados com os obtidos para peças em ABS. As alterações ocasionadas na superfície das amostras mostraram ser dependentes da composição do material e das condições operacionais empregadas no pré-tratamento. O PVC apresentou maior resistência química às soluções testadas do que o ABS, necessitando de condições de processo mais agressivas, como temperatura, tempo de imersão e concentração dos reagentes. Blendas com menores concentrações de PVC foram mais susceptíveis ao ataque químico. Superfícies com maior rugosidade e presença de poros, cavidades e reentrâncias distribuídos de forma homogênea, apresentaram melhor adesão da camada metálica. De todas as soluções testadas, a solução condicionante sulfocrômica, quando aplicada no tratamento das amostras de PVC e blendas PVC/ABS de 20/80 e 40/60, em concentração de 350 g/L de ácido crômico e 400 g/L de ácido sulfúrico, temperatura de 70 °C e tempo de imersão de 15 minutos, ocasionou deposição do metal em toda a superfície da amostras, as quais foram aprovadas nos testes de adesão e corrosão.Abstract : Aiming to replace the terpolymer ABS (acrylonitrile butadiene styrene) in the process of plating, in this work, the chemical modification of the surface of molded pieces of pure PVC (polyvinyl chloride) and blends of PVC/ABS in the proportions of 20/80, 40/60 and 60/40 was evaluated. The pieces were previously characterized by thermal and mechanical tests, such as thermogravimetry (TGA), differential scanning calorimetry (DSC) and tensile test and subjected to chemical pre-treatment under different operating conditions, varying the reagent concentration, temperature and treatment time. To evaluate the modificationcaused by the pre-treatment on the surface, the pure PVC and blends pieces were analyzed by scanning electron microscopy (SEM), infrared spectroscopy (FTIR/ATR), atomic force microscopy (AFM), contact angle and roughness. The samples were also plated and the quality of the adhesion of metallic layers was evaluated by visual inspection, adhesion and corrosion by salt spray and the results were compared with those obtained for ABS pieces. The alterations on the surface of the samples shown to be dependent on the material composition and operating conditions employed in the pre-treatment. PVC showed higher chemical resistance to the tested solutions than ABS, requiring more aggressive process conditions such as temperature, immersion time and concentration of reactants. Blends with lower PVC concentrations were more susceptible to chemical attack. Surfaces with higher roughness and presence of pores, cavities and recesses distributed homogeneously showed better adhesion of the metal layer. Of all solutions tested, the conditioning sulfochromic solution when applied to the treatment of samples of PVC and 20/80 and 40/60 PVC/ABS blends at the concentration of 350 g/L of chromic acid and 400 g/L of sulfuric acid, temperature of 70°C and immersion time of 15 minutes caused the deposition of metal on the entire surface of the samples, which were approved in adhesion and corrosion tests
Better Barking for ABS: Reform Proposals for the Asset-Backed Securities Market
Get PDFThe market for asset-backed securities (ABS) – financial instruments backed by underlying assets such as mortgages – suffered a major setback in 2007, as a cascade of downgrades and defaults brought turmoil to credit markets and the world economy. Authorities in the United States have since proposed sweeping changes to the ABS market. The Canadian Securities Administrators, representing provincial securities commissions, recently released a discussion paper proposing similar reforms, which would require: (i) sharply enhanced transparency in ABS structures, (ii) CEO certification of the adequacy of such structures, and (iii) disclosure of previous asset repurchases by the securities’ sponsor.Financial Services, asset-backed securities (ABS), credit markets
Influence of ABS Molecular Weight on the Surface Migration of Magnetic Particles in Injection Molding
No full textreservedLa crescente problematica dei batteri resistenti agli antibiotici ha stimolato lo sviluppo di superfici antibatteriche attraverso approcci fisici e chimici. Questo lavoro si propone di implementare soluzioni antibatteriche basate su approcci chimici, sfruttando particelle ferromagnetiche tramite l'effetto core-shell realizzato nell'ABS (Acrilonitrile Butadiene Stirene). L'obiettivo principale dello studio è determinare se questo effetto, combinato con l'influenza di uno stampo magnetico, possa favorire la concentrazione delle nanoparticelle magnetiche sulla superficie esterna, riducendone la presenza nella zona centrale. Questa strategia mira a creare un gradiente funzionale delle particelle, migliorandone l'efficacia e consentendo una possibile riduzione dei costi grazie alla diminuzione del quantitativo di particelle utilizzate.
Per raggiungere tale obiettivo, verrà esaminata l'influenza del peso molecolare e della viscosità sull'effetto core-shell. Il progetto prevede, in primo luogo, la caratterizzazione dei materiali per ottenere informazioni dettagliate sul loro comportamento e, successivamente, la ricerca dei parametri ottimali per i materiali utilizzati al fine di realizzare la miglior struttura core-shell. Sarà creato un compound di ABS contenente lo 0,5% di nanoparticelle magnetiche tramite un estrusore bivite co-rotante. Dopo aver determinato la composizione migliore tra i due materiali selezionati, si procederà allo stampaggio a iniezione. I campioni stampati saranno analizzati utilizzando un codice Python specifico per l'elaborazione dei dati.
Infine, i risultati ottenuti saranno verificati, discussi e analizzati, con particolare attenzione alla distribuzione delle nanoparticelle.The growing issue of antibiotic-resistant bacteria has driven the development of antibacterial surfaces through both physical and chemical approaches. This study aims to implement antibacterial solutions based on chemical approaches, utilizing ferromagnetic particles through the core-shell effect realized in ABS (Acrylonitrile Butadiene Styrene). The primary objective of the study is to determine whether this effect, combined with the influence of a magnetic mold, can promote the concentration of magnetic nanoparticles on the external surface, reducing their presence in the central region. This strategy seeks to create a functional gradient of the particles, enhancing their effectiveness and potentially reducing costs by decreasing the amount of particles used.
To achieve this goal, the influence of molecular weight and viscosity on the core-shell effect will be examined. The project involves, first, the characterization of materials to obtain detailed information about their behavior and, subsequently, the optimization of parameters for the materials used to achieve the best core-shell structure. A compound of ABS containing 0.5% magnetic nanoparticles will be created using a co-rotating twin-screw extruder. After determining the optimal composition between the two selected materials, injection molding will be carried out. The molded samples will be analyzed using Python code specifically designed for data processing.
Finally, the results will be verified, discussed, and analyzed, with particular attention to the distribution of the nanoparticles
Implementation of a PC-based ABS System with CAN-Bus Interface on an Experimental Platform
No full text[[abstract]]An experimental platform is constructed to test a designed CAN (Controller Area Network) interface of an ABS (Anti-lock Brake System). A PC-based ABS ECU with CAN interfaces is designed and implemented for testing. Four wheel speed signals and one brake pedal switch signal are sent to the CAN via the designed input interfaces. Through the CAN interfaces, on/off commands from the controller can drive the eight solenoid valves and a pump motor. Accordingly, all of the signals can be transmitted through the CAN bus in the ABS control system loop. Using the developed CAN I/O interfaces, a PC with a CAN interface card can receive the inputs and send out control signals to the ABS module. The developed circuits are experimentally verified in the platform. The proposed system incorporates a CAN bus configuration to reduce the complexity of the interconnections among ABS components
Characterization of glass fibre reinforced polyamide/acrylonitrile butadiene-styrene composite for automotive application
Get PDFPolyamide-6 (PA6), acrylonitrile-butadiene-styrene (ABS) and their blends are an important class of engineering thermoplastics that are widely used especially for automotive industries. Many efforts have been taken to improve the properties of both pure components and the blends. It was for this reason that the dynamic mechanical and rheological properties of PA6/ABS blend systems compatibilised by acrylonitrilebutadiene- styrene–maleic anhydride (ABS-g-MAH) was studied. The compatibiliser level was kept up to 5wt. % in the blends. Short glass fibre (SGF) was used to improve the stiffness of the compatibilised blends and the concentration was varied from 10 to 30 wt. %. Therefore, the reason behind of blending the PA6/ABS blends with short glass fibre was to balance the toughness and stiffness. The blends and corresponding composites were compounded using a co-counter twin srew extruder. Tensile, flexural and impact properties were determined using the injection moulded test samples according to ASTM standards. Dynamic mechanical analyses (DMA) were carried out to investigate the dynamic mechanical behaviour of the blends and composites. Rheological properties were carried out using dynamic and capillary rheometer. In general, the mechanical strength either dynamic (refer to DMA) or static conditions were improved by incorporation of compatibiliser to the PA6/ABS blends. The incorporation of SGF into the PA6/ABS blends enhanced the mechanical strength however, reduced the toughness of the composites. The rheological measurements confirmed the increased in interaction between the blend components with the incorporation of compatibiliser The compatibiliser has no favourable effect on the mechanical properties of the composites although it has significant effect on the blends of PA6/ABS. ABS-g-MAH increases the melt viscosity of the blends. The SGF increased the rheological properties especially viscosity and flowability of the composites. The optimum ratio compatibiliser and SGF concentration were successfully determined using power law and consistency index analysis. From the analysis the optimum ratio obtained was 1.5 wt. % for 50/50 and 60/40 PA6/ABS blends and 3 wt. % for 70/30 PA6/ABS blends. When the SGF introduced at 20 wt. % concentration, the values of n drastically decreased indicating more pseudoplastic nature for the composites and concluded that, the optimum concentration of SGF was about 20 wt. %
Word Picture of Carl Abs
No full text2 copies, Karl (Carl) Abs, Macklenburg, Germany, Hamburg Strongma
Estudo da degradação térmomecânica e fotooxidativa de poli(acrilonitrila-butadieno-estireno) para fins de reciclagem primária
Get PDFDissertação (mestrado) - Universidade Fderal de Santa Catarina, Centro Tecnologico, Programa de Pós-Graduação em Ciências e Engenharia de Materiais, Florianópolis, 2009O interesse da reciclagem primária do copolímero de acrilonitrila, butadieno estireno (ABS) é crescente, principalmente para a indústria automobilística e de eletrodomésticos que utilizam muito este material. Um dos problemas encontrados no re-processamento do ABS é a sua susceptibilidade a alterações estruturais devido à degradação térmica ou fotooxidativa. Normalmente, esses processos de degradação resultam na diminuição das propriedades mecânicas e mudança de propriedades óticas (principalmente amarelamento). Desta maneira, o conhecimento do processo de degradação do ABS e as modificações de propriedades físicas e químicas tornam-se importantes para avaliar a possibilidade de reciclagem deste material em aplicações sem a depreciação de custo do produto fabricado. Neste trabalho foi avaliada a degradação do ABS após envelhecimento térmico e fotooxidativo. A condição de envelhecimento foi escolhida com o intuito de simular a degradação que esse polímero é submetido durante seu ciclo de vida como materiais utilizados na indústria automobilística e de eletrodomésticos. As mudanças das propriedades físicas do ABS envelhecido e não envelhecido foram observadas a partir dos ensaios mecânicos de tração, impacto, análise dinâmico-mecânica (DMA) e pelo índice de amarelecimento. A Espectrometria no Infravermelho por Transformada de Fourier (FTIR) foi utilizada para verificar o aparecimento de bandas características do processo de degradação desse polímero. Os resultados mostraram que há redução das propriedades mecânicas e amarelecimento do ABS após o envelhecimento térmico e/ou fotooxidativo. Entretanto, pôde-se concluir que, apesar de constatado o envelhecimento no material quando reprocessado e/ou submetido ao envelhecimento fotooxidativo, esta redução pode não ser tão significativa, possibilitando a reutilização do material para a fabricação de peças técnicas de menor valor agregado; e que as misturas de ABS envelhecido/matéria-prima virgem, nas proporções estudadas, podem apresentar um desempenho similar ao ABS não reciclado.The interest regarding the primary recycling for Acrilonitrile Butadiene Styrene (ABS) is rising, mainly for vehicle and home appliances industry that have large scale consumption for this material. One of the main problems faced on ABS reprocessing is its susceptibility to structural changes due thermal and photo oxidative degradation. Normally, these degradation processes results in the mechanical properties decrease and optical properties changes (mainly yellowing). The acknowledgement of the ABS degradation process and the physical and chemical properties changes become important to evaluate the feasibility of recycling this material in applications without cost depreciation of manufactured products. In this study it was evaluated the ABS degradation after thermal and photo oxidative aging.The aging condition was chosen looking for simulate the degradation that this polymer is submitted during its lifetime as used materials in automobilist and home appliances manufacturers. The changed physical properties of aged and not aged ABS were investigated by techniques as mechanical tests of Tensile and Impact Strengths, Dynamical-Mechanic Analysis (DMA) and Cromatography as yellowing index. The Fourier Transform Infrared Spectroscopy (FTIR) was used to evaluate the aging process that inflicts in new characteristic bands. The results drove to the understanding that there is mechanical properties reduction so as the yellowing evolution for the ABS after thermal and/or photooxidative aging. Despite that, it was possible to conclude that even after acknowledged the material aging when reprocessed and/or submitted to the photooxidative aging, the reduction may not be so significant, making possible the material reallocation to the manufacturing of technical parts with lower added value, and that the ABS mixtures aged/raw material, in studied proportions, may deliver a similar performance as none recycled ABS
ABS-education-and-employment-1410.0
No full textThe repository includes ABS data and Jupyter Notebook. The ABS data “Education and Employment, ASGS and LGA, 2011, 2014-19” from “1410.0 - Data by Region, 2014-19” was created by the Australian Bureau of Statistics (ABS) that is available at (https://www.abs.gov.au/AUSSTATS/[email protected]/DetailsPage/1410.02014-19?OpenDocument). This data collection contains information about education and employment in Australia between 2014 and 2019. The ABS is a national statistical agency in Australia and provides a wide range of statistical data collections on economic, population, environmental, and social issues. We use the Jupyter Notebook to transform the ABS data into a required format for data insight generation
ABS-education-and-employment-1410.0
No full textThe repository includes ABS data and Jupyter Notebook. The ABS data “Education and Employment, ASGS and LGA, 2011, 2014-19” from “1410.0 - Data by Region, 2014-19” was created by the Australian Bureau of Statistics (ABS) that is available at (https://www.abs.gov.au/AUSSTATS/[email protected]/DetailsPage/1410.02014-19?OpenDocument). This data collection contains information about education and employment in Australia between 2014 and 2019. The ABS is a national statistical agency in Australia and provides a wide range of statistical data collections on economic, population, environmental, and social issues. We use the Jupyter Notebook to transform the ABS data into a required format for data insight generation
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