Resumo Membranas de compósitos Pd/α-Al2O3 com uma e duas camadas de Pd foram preparadas pelo processo electroless plating sobre tubos cerâmicos porosos. A análise de espectroscopia por dispersão de energia confirmou a composição química do suporte cerâmico (Al e O) e da membrana com Pd (Al, O e Pd), bem como a espessura da camada de Pd de 0,8 μm (uma camada) e 1,3 μm (duas camadas). As imagens de microscopia eletrônica de varredura mostraram que a superfície da membrana foi mais uniforme com uma camada do que duas camadas de Pd. O difratograma de raios X registrou picos referentes à fase α-alumina. A porosimetria por intrusão de mercúrio apresentou diâmetro de poro em torno de 5 nm e volume máximo de Hg intrudado de 0,0081 cm3.g-1. Os testes de permeabilidade aos gases mostraram que as membranas possuem seletividade α de 3,79 para o par H2/CO2 com um camada de Pd e de α=3,43 para o par H2/CH4 com duas camadas de Pd.

Abstract Composite membranes Pd/α-Al2O3 with one and two Pd layers were prepared by electroless plating process on porous ceramic tubes. The analysis by energy dispersive spectroscopy confirmed the chemical composition of the ceramic support (Al and O) and of the membrane with Pd (Al, O and Pd), as well the thickness of Pd layer of 0.8 μm (one layer) and 1.3 μm (two layers). Scanning electron microscopy images showed that the surface membrane was more uniform with one layer than two Pd layers. The X-ray diffraction pattern recorded peaks assigned to α-alumina phase. Mercury intrusion porosimetry showed a pore diameter around 5 nm and maximum intruded Hg volume of 0.0081 cm³.g-1. Gas permeability tests showed that the membranes had selectivity α of 3.79 for H2/CO2 pair with one Pd layer and α=3.43 for H2/CH4 pair with two Pd layers.

Polymeric materials are greatly used in industry due to their versatility in application generating therefore, large quantities of solid waste. Population growth in urban areas, with living quarters mainly in residential buildings, face discomfort caused by noise, particularly by impact noise. Aiming at reducing the amount of polymeric material disposed of in the environment and at providing alternatives of reuse, together with the possibility of reducing noise impact from construction works, agglomerates of polyurethane skin (PUs) have been developed. The recycling process of PUs was developed through variations in particle size and pressing temperature of agglomerates. PU agglomerates of coarse particle size, hot pressing process and close cell structure presented reductions in noise level up to 20 dB, showing that it is suitable for acoustic insulation.