Abstract: Rigid foams characterized by carbodiimide and isocyanurate linkages are prepared by catalytically condensing an organic polyisocyanate in the presence of certain quaternary boron salts.

Abstract: A non-swellable three-dimensional polymer having a component which is a residue of an optically active compound, which residue is chemically removable from said polymer to leave behind in the physical structure of said polymer a void corresponding to the size and shape of said residue of optically active compound, and a particular steric arrangement of functional groups within the void of said polymer corresponding to the chemical structure of said residue of optically active compound, the original polymer having recurring units of the formulas ##STR1## wherein A, C and D are residues bonded to B of compounds which residues are polymerizable or polycondensable and B is a residue of an optically active compound; a process for preparing such polymer and the form of such polymer containing such void and free of the residue of optically active compounds.