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Article Dans Une Revue Journal of Applied Polymer Science Année : 2009

Mixed percolating network and Mechanical properties of PP/talc composites

Résumé

Injected polypropylene/talc composites were studied to evaluate the conditions leading to the formation of a mixed talc-polymer crystalline lamellae percolating network and the influence of such a network on the nanocomposite mechanical properties. The talc used was either conventional micron sized (conventional talc) or submicron sized particles (micro-talc). In the case of micro-talc, several talc fractions were studied, ranging between 3 and 30 wt.%. The nanocomposite crystallinity was characterised by differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS). It was found that talc acted as a nucleating agent, and that only the alpha-phase was detected. Though the quantification on a Wilchinsky diagram, the talc particles were found to lie in the sample plane, the PP crystalline lamellae being orthotropically distributed perpendicularly to the talc particles. The mechanical properties of the composites were tested in different directions by tensile and compression tests. The mechanical behaviour of the composites confirms the microstructural model. For low talc loadings, the composite moduli could not be well fitted by a law of mixtures. The large difference between the observed and predicted moduli was attributed to the formation of a mixed percolating network, including talc particles and PP crystalline lamellae. At high talc loadings, that is when the mixed percolating network is completely formed, the reinforcement can well be described by a parallel coupling, which indicates a classical reinforcement mechanism. Finally, the value of the critical talc fraction, at which the mixed percolating network is formed, is discussed in function of the talc.

Domaines

Matériaux

Dates et versions

hal-00586397 , version 1 (15-04-2011)

Identifiants

Citer

Djamel Frihi, Karine Masenelli-Varlot, Gérard Vigier, H. Satha. Mixed percolating network and Mechanical properties of PP/talc composites. Journal of Applied Polymer Science, 2009, 114 (5), pp.3097-3105. ⟨10.1002/app.30890⟩. ⟨hal-00586397⟩
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