The addition of kaolin in polypropylene homopolymer (PP) leads to a de
crease in impact properties. This is due to the lack of adhesion betwe
en the PP and the filler. An interesting way of improving adhesion bet
ween the two components is to coat the mineral filler in a latex. The
efficiency of the coating operation depend on the chemical nature of t
he coating agent (i.e, the latex) and the coating conditions. The coat
ing conditions were evaluated by measuring the electrokinetic potentia
ls of the kaolin and latex particles. The different analytical techniq
ues used proved the fixation of the latex onto the kaolin. The results
of mechanical testing show that the coating of kaolin leads to an inc
rease in impact strength of 50%.