In this work, the manufacture of particles from polybutylenterephthalate (PBT) and of composites from PBT and zinc oxide and bentonite nanoparticles is described. From the admixing of nanoparticles, improved properties are expected. For the production, the PGSS process with supercritical carbon dioxide as auxiliary medium is used. Spherical particles can be obtained from pure PBT as well as from the composites. The degree of separation of the additives is visualised in TEM pictures. SEM pictures show, that in dependence of the spraying conditions, particles with different morphologies are formed. The shape ranges from the perfect sphere to completely irregular particles or fibres. The apparent density appears to be an indicator for the sphericity of the particles. A suggestion for a correlation between spraying conditions and the apparent density is given. (C) 2009 Elsevier B.V. All rights reserved.