The Adhesion Phenomena in Polypropylene/Wollastonite Composites
Iztok Švab,a* Vojko
Musil,a and Mirela Leskovacb
a University of Maribor, FEB Maribor, Institute of Technology, Razlagova
14, 2000 Maribor, Slovenia,
E-mail: iztok.svab@uni-mb.si
b University of
Zagreb, Faculty of Chemical Engineering and Technology, Marulićev trg 19, 10000
Zagreb, Croatia
Abstract
Modification of polypropylene (PP) with wollastonite fillers was investigated in
this paper. Three types of different silane pretreated wollastonite mineral
filler were used for preparation of binary PP/wollastonite composites. The
composite samples were homogenized in a Brabender Plasti-Corder kneading chamber
and compression moulded into plates on a laboratory press. The adhesion between
the wollastonite fillers used in this study and the PP matrix was predicted on
the basis of the calculated adhesion parameters (work of adhesion, interfacial
free energy and spreading coefficient) obtained by the surface free energy of
pure materials. The contact angle method was used to determine surface free
energy of components. The obtained values of adhesion parameters at the
interface in the composites were correlated with mechanical properties as well
as morphology observations of corresponding composites and were proved to be in
relatively good agreement with the mechanical property measurements. Stronger
adhesion in investigated composites has reflected in higher yield stress and
tensile strength at break but in lower elongation at break and impact resistance.
Key words: polypropylene
composites, wollastonite, surface energy, adhesion, morphology, mechanical
properties