Glass Fibre Sizing and Surface Treatment
topic
Sizing composition: film formers (PVA, polyurethane, epoxy—30-60%, providing strand integrity), coupling agents (silanes 0.1-2%—γ-aminopropyltriethoxysilane for epoxy, γ-methacryloxypropyltrimethoxysilane for polyester—improving fibre-matrix adhesion), lubricants (cationic softeners reducing friction), and antistatic agents. Application at 0.5-2% on glass weight. Compatibility with resin system critical (thermoset vs. thermoplastic sizing).
Role
Sizing chemistry fundamentally determines composite interphase properties, affecting interfacial shear strength (20-80 MPa range with proper sizing), moisture resistance, and processing characteristics (wetting, impregnation).