Tatiana Louise Avila de Campos Rocha

Comparison between Rice Husk Ash and Commercial Silica as Filler in Polymeric Composites

The use of rice husk ash (RHA) as filler in polymeric materials has been studied in different polymers. Research reported that RHA may successfully replace silica. The silica production process using ore demands high energy input and produces considerable amounts of waste. Therefore, the replacement of silica by RHA may be economically and environmentally advantageous, reducing environmental impact and adding value to a waste material. In this context, this study characterizes and compares RHA of different sources (moving grate and fluidized bed reactor) with commercially available silicas to assess performance as filler in polymeric materials. Samples were characterized by X-ray fluorescence, loss on ignition, X-ray diffraction, grain size, specific surface area, specific weight, and scanning electron microscopy. The results show that RHA may be used as a filler in several polymeric materials.

Influence of Cellulose Pulp Waste in Plastering Mortar

The objective of the present study was to assess the properties of plastering mortar that uses cellulose pulp waste as absorbent material. Waste was characterized by thermogravimetric analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD, and absorption of aqueous solutions with pH variations. The incorporation of 0.5%, 1% and 1.5% of waste in a plastering mortar prepared with Portland cement, lime and sand (1:1:6) was proved viable. Mortars were analyzed and compared with a control mortar. The properties of fresh mortars analyzed were: consistency index, squeeze-flow, incorporated air, water retention and density. The properties of hardened mortars analyzed were (after 28 days): tensile resistance on flexural stress, compression strength, density, absorption by capillarity and capillarity coefficient, total water absorption, void index, specific weight and linear retraction. The addition of waste resulted in improved mechanical properties, compared to the control mortar. An increase of 4% was observed in tensile resistance on flexural stress, and of 7% in compression strength for the mortar prepared with 1.5% cellulose pulp.

DESENVOLVIMENTO DE RESINA À BASE DE POLIESTIRENO EXPANDIDO (EPS) RESIDUAL

Resumo O acúmulo de poliestireno expandido (EPS) em sua forma pós-consumo é atualmente um motivo de preocupação em termos de impacto ambiental. Desenvolve-se, portanto, diferentes formulações de uma resina veículo para tinta que aproveitam este material como matéria-prima, através da dissolução do mesmo em solventes de origem natural extraídos da casca de laranja, quais sejam o próprio óleo essencial e seu componente majoritário D-limoneno, e em C9 aromático, junto aos copolímeros termoplásticos ESBR, SIS, SBS e SEBS e óleo de soja epoxidado (ESBO) como plastificantes. Obtém-se, em diferentes formulações, um desempenho favorável à futura adição de pigmento e demais aditivos, em termos de compatibilidade, elasticidade e aderência avaliados conforme normatização nacional e internacional. Observa-se especial sucesso com o uso do copolímero SEBS e do ESBO como plastificantes, concomitantemente à eficiência semelhante dos três solventes utilizados, o que permite a substituição do C9 aromático por componentes de origem natural e residual. Palavras-chave: Poliestireno expandido; D-limoneno; Polímeros; Tinta.