Abstract: Process for making a solid compound by precipitation, using a high intensity mixing reactor and comprising the steps of (A) introducing a first fluid material containing a first reactant and a second fluid material containing a second reactant into said reactor, in order to obtain a mixed fluid, in order to cause the first reactant to react with the second reactant to form a solid compound by precipitation in the mixed fluid; (B) withdrawing the mixed fluid containing the precipitated solid obtained in step (A) from the reactor, and; (C) optionally separating the precipitated solid compound from at least one fraction of the mixed fluid.

Abstract: Use of nanoparticles of barium sulfate or of calcium carbonate, with a particle size of less than or equal to 150 nm and greater than or equal to 0.5 nm, as filler in transparent polymer compositions. The compositions obtained simultaneously show good scratch resistance, good impact strength, good tensile strength, good heat stability and good visible and UV radiation stability, while at the same time conserving excellent transparency. The compositions may be used as replacement materials for glass in the motor vehicle sector and in the optics sector.