Abstract: The invention relates to the use of chemical grafting to produce a stable liquid composition that is capable of hardening following an optional polymerization process. Under the invention, in order to produce a composition that is liquid, at least initially and prior to any polymerization, a polymerizable organic acid comprising at least two double bonds in resonance is combined in a solvent with an inorganic filler having at least one hydroxylated group with the help of a catalyst acting as a radical upon said organic acid. By adjusting the concentration of catalyst and using a polymerizable monomer solvent, the liquid composition may be hardened by polymerization after the initial grafting reaction. By ensuring that a portion of the organic acid retains free bonds that have not combined with filler, it is also possible to induce the composition to become chemically attached to a resin or to reinforcing fibers. The invention may be applied to the production of molded objects.