Solid-state microcellular acrylonitrile-butadiene-styrene foams

Microcellular ABS foams are a novel family of materials with the potential to significantly reduce material costs in a number of applications that cur rently use solid polymer. ABS foams were produced using carbon dioxide in a solid-state process. Solubility and diffusivity of CO2 in ABS was measured , and the latter was found to depend significantly on the gas concentration . The useful range of process-space for ABS-CO2 was characterized. Closed c ell ABS foams were produced with densities ranging from 1.03 g/cm(3) (almos t completely solid) to 0.09 g/cm(3). It was determined that there are many different processing conditions that can produce microcellular ABS foams th at have the same density. The cell nucleation density was of the order of 1 0(11) cells per cm(3), and the average cell sizes observed ranged from 0.5 mum to 5.6 mum.