Abstract: The invention provides a solid composite material comprising a matrix formed from a particulate or fibrous material and a cured thermosetting resin, wherein the cured thermosetting resin is derived from an oxidative cleavage product selected from aldehydes and peroxides and mixtures thereof formed by the oxidative cleavage of an unsaturated bond in an unsaturated plant or animal oil, other than the ozonolysis cleavage product of cashew nut shell liquid. Also provided is a process for the production of aldehydes and/or peroxides, which process comprises the treatment of a vegetable oil with ozone (e.g. in the presence of an alcohol as a solvent for the oil) so that hydroperoxides are produced, and the reductive cleavages of the hydroperoxides with a reducing sugar.