Paper number 888

EFFECTS OF FIBRE SIZING ON DAMAGE DEVELOPMENT IN UNIDIRECTIONAL GLASS/EPOXY COMPOSITES

M. Kharrat ¹,³ T. Monlèon¹,² L. Carpentier³ A. Chateauminois¹ and M.L. Maspoch²

1Laboratoire d'Ingéniérie et Fonctionnalisation des Surfaces
Ecole Centrale de Lyon, BP 163, 69131 Ecully Cedex, France
2Departament de Ciència dels Materials i Enginyera Metallurgica
Universitat Politècnica de Catalunya, 647 Avda Diagonal, 08028 Barcelona, Spain
3Laboratoire de Tribologie et Dynamique des Systèmes
Ecole Centrale de Lyon, BP 163, 69131 Ecully Cedex, France

Summary

. The micro and macro mechanical behaviour of unidirectional glass/epoxy composites differing by their fibre sizing has been investigated. Three different model sizing have been considered: A1100 only, A1100 with an epoxy prepolymer (DGEBA) and A1100 with a linear polyurethane (PU). The composite based on the A1100/PU sizing was characterised by a much greater sensitivity to damage development under impact and fatigue loading in flexural mode. This difference was related to a low shear strength, which induced an enhanced delamination under mechanical loading. On the other hand, micro-indentation tests were unable to reveal any difference in the fibre/matrix interfacial shear strength. The low macro-mechanical properties of the A1100/PU composite were interpreted by considering the highly heterogeneous fibre distribution which resulted from the low wettability of the sizing by the epoxy matrix. The main effect of the sizing was thus to affect the impregnation process during manufacturing, rather than modifying the intrinsic mechanical properties of the interface.

Keywords

fibre sizing, interface, fatigue, strength, micro-indentation, micro/macro mechanical properties, glass/epoxy.