Abstract: The invention relates to a process for the preparation of a composition to be extruded comprising a polymer and a filler of solid particles comprising a stage of mixing the filler of solid particles with particles or granules of the said polymer, if appropriate in the form of an aqueous suspension. The invention is particularly simple, and the final material is in better mechanical properties than those obtained by direct incorporation of the solid filler in the polymer or copolymer. This improvement is very substantial, in particular with regard to the impact strength of the final material. The invention also relates to a polypropylene-based composition comprising a filler of solid particles, such as kaolin, exhibiting a high flexural modulus and a good impact strength.

Abstract: The present invention relates to a solid catalyst component for the polymerization of olefins, making it possible to obtain polymers or copolymers exhibiting a high Mz/Mw, generally higher than 3, and a high Mw/Mn, generally higher than 5.5. In the solid component according to the invention, titanium is present in a proportion of at least 2.5% by weight and a diester of phthalic acid is present in a proportion of less than 7% by weight.