Resumo: O PHB (Poli-3-hidroxibutirato) é um termoplástico biodegradável sintetizado por fermentação submersa a partir de matérias-primas renováveis. A utilização de fibras naturais tem sido pesquisada visando melhorar as propriedades e reduzir o custo do PHB. O objetivo deste trabalho foi o estudo das propriedades mecânicas (resistência à tração), térmicas (Análise termogravimétrica,TGA, e Calorimetria Exploratória Diferencial, DSC) e reológicas (torque em câmera de mistura e Índice de Fluidez) do PHB e de compósitos de PHB/pó de madeira processados e irradiados. Foram preparados compósitos com concentrações de PHB/pó de madeira de 90/10, 80/20 e 70/30 (m/m). Os materiais foram processados através das seguintes etapas de processamento: calandragem, fragmentação, extrusão, granulação, secagem e moldagem por injeção para confecção dos corpos de prova. A incorporação do pó de madeira aumentou o grau de cristalinidade e a temperatura de cristalização do polímero, e nos compósitos PHB/pó de madeira 80/20 e 70/30 a rigidez do material aumentou. A irradiação após o processamento (dose de 30 kGy) provocou aumento da rigidez do PHB puro e dos compósitos PHB/pó de madeira 90/10 e 80/20, embora outras propriedades tenham decrescido. O compósito PHB/pó de madeira 70/30 apresentou os melhores resultados em termos econômicos e de processamento. Palavras-chave: Poli-3-hidroxibutirato, compósitos PHB/pó de madeira, propriedades térmicas, propriedades mecânicas, irradiação, processamento. Study of Mechanical and Thermal Properties of the Polymer Poly-3-Hydroxybutyrate (PHB) and PHB/Wood Flour CompositesAbstract: PHB (Polyhydroxybutyrate) is a biodegradable thermoplastic synthesized by submerse fermentation of renewable raw materials. The use of natural fibers has been largely researched to improve PHB properties, as well as reducing its cost. The purpose of this work was the study of the mechanical, thermal properties and rheological analyses (torque in mixer camera and melt flow index) of processed and irradiated PHB, as well as PHB/wood flour composites. PHB/wood flour composites were prepared with PHB/wood relation of 90/10, 80/20 and 70/30 (w/w). Both pure PHB and composites were processed through the following steps: calendering, milling, extrusion, second milling, drying and injection molding to make test specimens. Mechanical properties (strength resistance) and thermo analyses (Thermogravimetric Analysis, TGA and Differential Scanning Calorimeter, DSC) tests were carried out. The introduction of the wood flour increased both polymer crystallinity and crystallization temperature. IntroduçãoNovos materiais compósitos estão sendo desenvolvidos, combinando-se matrizes termoplásticas e cargas reforçativas de origem lignocelulósicas. Devido à intensificação das questões ambientais, pesquisas envolvendo o emprego de polímeros biodegradáveis como substitutos dos polímeros sintéticos convencionais aumentaram nos últimos anos, assim como o uso de fibras naturais como reforço dos mesmos. As vantagens da utilização de reforços lign...

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We analyze graphene obtained by electrochemical exfoliation. This showed an interesting process for obtaining fast and low cost exfoliated graphene. Within a few minutes a large amount exfoliated graphite oxide was produced. Analysis by Raman spectroscopy of the exfoliated graphene showed the effectiveness of the process and the factors that may intensify the disorder of graphene obtained.

Graphene was obtained by electrochemical exfoliation of graphite and metal/graphite electrodes of different compositions and electrical conductivities. Metal/graphite electrodes were prepared using high purity copper and nickel precursor and commercial graphite. Processes of rapid expansion and direct exfoliation of graphite in a H2SO4 solution were observed using voltages from 2V to 15V and currents of 0.03 mA to 0.08 mA. The total time for each process was one hour and the maximal concentration of few layers graphene flakes was 0.002 mg/mL. X rays powder diffraction of the expanded electrodes showed the effect of the electrochemical process in the crystallinity and the increasing of interlayer distance. A characterization of a large amount of graphene flakes was performed by Raman spectroscopy and optical microscopy. Typical size of the flakes are between 1 μm and 10 μm and the Raman spectra indicate number of layers from single or bilayers to approximately ten layers. The greatest variations in thickness of flakes are observed when the intercalation process concludes before the expansion of the layers. A low degree of oxidation and of structural defects was characteristic of the experiments with lower acid concentration.

The increase in waste generation affects the daily lives of millions of people. This study is about the waste of the polypropylene and oyster shell. Some of the present research focuses on strategic proactive measures incorporating life cycle analysis, and others on end-of-pipe, traditional waste management technology evaluations. In all recovery actions, economic benefits are related with direct and indirect gains. Decreasing the use of raw materials and waste materials, obtaining valuable spare parts and other financial opportunities like second hand market are among direct gains. The objective is meet the waste of the polypropylene and oyster shell and measure the structure of reverse logistic to these waste. The structure of the reverse logistic is to increaser amount more volume the waste and to be viable to treatment. The study intend approach the chain reverse of the waste and show the limitation and opportunities this process. Is hoped to find the results of the characterization and discover what ways is possible to application.