New acrylic bone cements were prepared from alumina particles previously treated by 3-(trimethoxysilyl)propylmethacrylate (gamma-MPS) and embedded in poly(methylmethacrylate-co-ethylacrylate) beads with about 7 mol% of ethyl acrylate repeating units. The encapsulation was performed through a conventional suspension polymerization process. The influence of (i) the concentration of the dispersion stabilizer and (ii) the alumina content upon the shape, size, and size distribution of the acrylic beads was studied. Cements were prepared from each batch by hand-mixing alumina-filled acrylic beads with a liquid monomer mixture containing methyl methacrylate, n-butyl methacrylate, and N,N-dimethyl-p-toluidine. Benzoyl peroxide was previously added to the solid part. The powder-to-liquid ratio was equal to 2 for each formulation. Compressive strength of cured cement decreases with alumina content, whereas compressive modulus remains roughly constant. These results are in contradiction to those obtained for cements based on a mixture of gamma-MPS-treated alumina and unfilled acrylic beads. Nevertheless, they are interpreted in terms of alumina arrangement in the cement. In the first case, alumina particles contribute to the reinforcement of the dispersed acrylic phase, with poor benefits for the whole materials. In the second case, they allow the reinforcement of the continuous acrylic phase and, therefore, the cement's one.

Aluminum (Al) matrix composite materials reinforced with graphite flakes (GF) and pitch-based carbon fibers (CF) were fabricated by solid-liquid phase sintering with a small amount of Aluminum-Silicon eutectic alloy (Al-12wt%Si). The amount of Al-Si is optimized for a carbon content of 50 vol.% in order to achieve, in the plane of GF reinforcement, a higher thermal conductivity (TC) and a lower coefficient of thermal expansion (CTE) compared to identical composite material fabricated by conventional powder metallurgy route. Al/(GF+CF) composite materials were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray microscopy and X-ray tomography in order to highlight the distribution of the Al-Si liquid phase and the formation 2 of a carbon network in the aluminum matrix. A small amount of CF allows to control the through-plane CTE without affecting significantly the in-plane TC of the Al-C composites. The (GF+CF) mixture and the solid-liquid phase sintering allow to achieve a TC of 410 W/m.K (in-plane direction) and a CTE of 2.4×10-6 /K (trough-plane direction), which is, for example, applicable for lightweight heat sink material.