Paper number 262

MECHANICAL BEHAVIOUR OF POLYPROPYLENE COMPOSITES CONTAINING ULTRAFINE PARTICLES. CORRELATIONS WITH GRANULOMETRY AND MICROSTRUCTURE

P. Mareri1, S.Bastide1, N. Binda1, and A. Crespy1

1Laboratoire Matériaux Matrices Minérales et Organiques, Ecole des Mines d'Alès, 30319 Alès Cedex

Summary It is now well-known that the introduction of a mineral filler in a thermoplastic matrix increases Young modulus but dicreases impact strength.
The use of ultrafine mineral particles is one of the solutions for avoiding this decrease providing that the particles size remains small. In this study, we used three kaolins with differents particle size as fillers in a polypropylene matrix.
Image analysis was used to characterize the particle size in situ.
The results we obtained show that :
- The initial particle size can be noticeably modified. Indeed, particles of small tend to agglomerate.
- The microstructure of the matrix is modified, but not enough to explain the mechanical properties variations.
- The mechanical properties depend widely of the presence of aggregates.To confirm this point, a surface treatment was used to scatter the particles. We noticed an increase of the impact strength, due to the vanishing of the aggregates.
Keywords mineral filler, particle size, polypropylene, polymer matrix, particle-reinforced composites, image analysis, mechanical properties, impact strength.

Theme : Mechanical and Physical Properties ; Dynamic, Impact and crashworthiness

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