Aluminum Powder Reinforced Polyurethane Foams Derived from Castor Oil

Abstract

In this paper was evaluated the effects of Aluminum (Al) powder content in Polyurethane (PU) foam from castor oil with different weight percentages (10–40 wt%). The pure and metallic foams were characterized by scanning electron microscopy, optical microscopy, apparent density, X-ray diffractometry, spectroscopy infrared, thermogravimetry techniques, and mechanical tests. The results showed that the residue of the aluminum powder reinforced with polyurethane caused an increase in the density of the composites when compared to pure PU, which directly influenced the morphological, physical, chemical, thermal, and mechanical properties. This fact occurred because metallic foams exhibited a higher number of cells with a smaller cell size as the amount of Al content was increased. The addition of 40 wt% Al on the PU foam showed the highest density and impact strength in 0.068 g/cm3 and 41.2 J/m2, respectively. Results indicated that the addition of aluminum powder was hydrogen-bonded to PU molecular chains, and acted as a crosslinking agent, increasing the foam's density. The TG and DTG analyzes showed that the insertion of the aluminum powder improved the thermal stability of the metallic foams when compared to pure PU, as well as impact tests.