Materials Research
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13556
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6 resultados
Resultados da Pesquisa
Item Evaluation of aqueous coffee husks extracts as a corrosion inhibitor of 1020 carbon steel in 1 mol L-1 HCl solution(ABM, ABC, ABPol, 2019) Ramos, Samantha Alcântara Fernandes; Senna, Lilian Ferreira de; Lago, Dalva Cristina Baptista doCorrosive processes in acidic medium reduce the performance and durability of metallic materials, causing problems to several industries. Corrosion inhibitors are commonly used to decrease these effects. As these inhibitors must be ecologically friendly currently, this work evaluated the anticorrosive effect of natural extracts of coffee husks (Coffea arabica L.) in the protection of carbon steel in 1 mol L-1 HCl solution. Extractions were performed using water as the extraction solvent. The polyphenols content increased with the extraction temperature, and the extracts were produced using 100 ºC. Extract concentrations of 10, 20 and 30 % v/v were analyzed as inhibitors for carbon steel in acid medium, using weight loss and electrochemical tests, as well as scanning electron microscopy. There was an increase in the inhibition efficiency as the extract concentration increased, reaching values around 97 % using 30 %v/v of extract for the weight loss tests.Item Thermomechanical properties of corn starch based film reinforced with coffee ground waste as renewable resource(ABM, ABC, ABPol, 2019) Gazonato, Elisa Camarin; Maia, Amanda Alves Domingos; Moris, Virgínia Aparecida da Silva; Paiva, Jane Maria Faulstich deStarches polymeric films offer several advantages for the replacement of synthetic polymers due to their biodegradability, non-toxicity, availability and low cost. However, the high biodegradation potential can cause fragility, considering some fundamental mechanical properties. Therefore, starch based polymeric films were reinforced incorporating lignocellulosic waste from coffee grounds postconsume. The effect of incorporation of coffee ground in cornstarch matrix and polymer interaction on morphology, thermal and mechanical properties were investigated. The characterization analyzes were based on Dynamic Mechanical Thermal Analysis (DMTA), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Scanning Eletronic Microscopy (SEM). The coffee ground behaved as reinforcement agent according tensile values. Thermochemical conversion showed that polymeric films molding did not change his thermal stability. In temperature range was possible to observe the devolatilization, organic and inorganic compounds decomposition. SEM images showed the coffee ground adhesion in the polymer matrix promoting a better mechanical tensile strength.Item Study of coffee grounds oil action in PVC matrix exposed to gamma radiation: comparison of systems in film and specimen forms(ABM, ABC, ABPol, 2017) Silva, Lindomar Avelino da; Almeida, Tainá Medeiros Bastos de; Teixeira, Rebeca Valgueiro; Araújo, Elmo Silvano de; Aquino, Kátia Aparecida da SilvaThe poly (vinyl chloride), PVC, undergoes changes in its physicochemical properties when it is exposed to gamma radiation. Thus, the radiolytic stabilization of PVC is one way for obtain a material with radiation resistance. In this work, we studied the coffee grounds oil as PVC radiolytic protection in two systems forms: PVC film and PVC specimen. The systems were irradiated at sterilization dose of medical devices and viscosity measurements were performed. According to viscosity assays of PVC films, there was a 67% protection in polymer matrix promoted by the oil. On the other hand, the mean viscosity molar mass (Mv) of PVC specimens increased about 13%, indicating predominance of crosslinking effect, however samples containing the oil showed no Mv significant changes. Therefore, the oil can be considered a PVC radio stabilizing substance and open a way for use of sustainable additive in PVC industry.Item Roasted coffee extracts as corrosion inhibitors for mild steel in HCl solution(ABM, ABC, ABPol, 2016) Souza, Elaine Cesar do Carmo Assumpção de; Ripper, Beatriz de Andrade; Perrone, Daniel; D’Elia, ElianeThe behavior of roasted coffee extract and its isolated high molecular weight fraction have been investigated as carbon steel corrosion inhibitors in HCl solution by weight loss measurements, potentiodynamic polarization curves, electrochemical impedance and scanning electron microscopy analysis. All results showed that the high molecular weight fraction, rich in melanoidins, present an important role in the inhibitory action of the roasted coffee extract in the acid corrosion of carbon steel.Item Biodegradation study of a novel poly-caprolactone-coffee husk composite film(ABM, ABC, ABPol, 2016) Borghesi, Daiana Cristina; Molina, Maíra Fernanda; Guerra, Marcos Antônio; Campos, Maria Gabriela NogueiraPlastic disposal is a worldwide issue due to its long degradation time. Environmentally degradable polymers (EDPs) have received considerable attention because of their faster degradation. However, the use of EDPs is limited by high cost and restricted properties. The incorporation of organic fillers is an alternative to reduce cost while increasing biodegradation. Poly-caprolactone (PCL) is a biodegradable polyester compatible with organic fillers. Coffee husk (CH) is a sub-product of coffee processing with potential use as organic filler. We prepared a novel PCL-CH composite film and investigated the effects of CH incorporation on the biodegradation of PCL. Biodegradation study was carried out in soil for 120 days, and evaluated by weight loss measurements. Additionally, soil microbiological and granulometric analyses were performed. Bacteria and fungi were found in the soil that was classified as sandy. The composite film degraded twice faster than PCL film probably due to the adhesion of microorganisms on the coffee husk.Item Particles of coffee wastes as reinforcement in polyhydroxybutyrate (PHB) based composites(ABM, ABC, ABPol, 2015) Reis, Kelen Cristina; Pereira, Lucinéia; Melo, Isabel Cristina Nogueira Alves; Marconcini, José Manoel; Trugilho, Paulo Fernando; Tonoli, Gustavo Henrique DenzinThe objective of the present study was to evaluate lignocellulosic particles from sub-products of the coffee industry (coffee parchment - CP and husk - CH) into polyhydroxybutyrate (PHB) as a promising reinforcing filler in the biocomposites. The effects of type (CP or CH) and content (neat, 10% and 20%) of coffee wastes on the thermal, mechanical, microstructural and physical properties of the ensuing composites were evaluated. Thermal stability of the composites was improved by the coffee residues at different contents, while degree of crystallinity was decreased with the inclusion of CP. The addition of 10% of CP has not influenced significantly the tensile strength (TS) and Izod strength (IS), in relation to the neat PHB. Tensile strength (TS), MOE and Izod strength (IS) of the composites have increased significantly with the inclusion of 20% of CP. The increase in the content of coffee waste particles increased the water absorption of the composites.