Paper number 1037


O. Rodriguez1 , V. Morales1, M.C. Gutierrez1, J. Rubio2

1Departamento de Materiales Compuestos, Instituto Nacional de Técnica Aeroespacial.
Ctra. Ajalvir Km. 4 , 28850 Torrejón de Ardoz, Madrid, Spain.
2Instituto de Cerámica y Vidrio. (CSIC). Ctra. Valencia Km.24,3, 28500. Arganda del Rey. Madrid. Spain.

Summary It's well known that material's adhesion is the result of several phenomena of mechanical and physicochemical character, these last ones rely on the interactions between atoms or molecules in the surface of the materials in contact. So, to approach the adhesion problems it is necessary to have a good knowledge of the surfaces and their characteristics. Inverse Gas Chromatography (IGC) has proved to be a powerful tool for characterising the surface energy of solid materials. IGC can determinate the surface capability of interaction with non-polar compounds and its acidic or basic character, its affinity to functional groups. There are several methods described in the literature for the evaluation of surface characteristics by IGC.
Polypropylene is an attractive thermoplastic material because of its low price, good processability and recyclabilty, but it presents serious adhesion problems with coatings and reinforcements.
In this work, the surface characterisation of several polypropylenes in terms of surface free energy is measured by IGC: non-polar character, acid and basic character and affinity to OH groups. The same is done on glass beads, without or with surface modification. Calculations are made of the interaction (energy per surface unit) between the possible matching materials. Some specimens are prepared with the available material, and some mechanical testing is done.
Keywords reinforced polypropylene, glass-olypropylene interface, inverse gas chromatography, surface properties and surface modification.

Theme : Interface and Interphase ; Physical Properties

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