New Particles Using Sedimentation Polymerisation

Monodisperse spheres of millimetre diameter, containing N,N' dimethyl-acrylamide and acrylic acid with different compositions have been produced via the 'sedimentation polymerisation' tehnique. To modify properties, a templating method was used to induce pore formation. Here, a series of monodisperse spheres can be produced with controlled size, porosity and morphology. A new approach to generate interpenetrating organic-inorganic hybrid spheres, using tetraethyl-orthosilicate as a precursor, is also disclosed. Such uniformly sized particles can, upon drying and pyrolysis above 500 C, yield uniform inorganic spheres of high regularity and surface area. A number of techniques, including optical and electron microscopes, X-ray analysis and atomic force microscopy, were used to investigate morphology and elemental distribution. In addition to controlling porosity, our procedure can produce interpenetrating organic-inorganic networks in particulate form with higher homogeneity, better thermal stability and less shrinkage than the original inorganic network.