Mechanical and thermal expansion properties of glass fibers reinforced PEEK composites at cryogenic temperatures

Polyetheretherketone (PEEK) has been widely used as matrix material for high performance composites. In this work, 30% chopped glass fibers reinforced PEEK composites were prepared by injection molding, and then the tensile, flexural and impact properties were tested at different temperatures. The modulus, strength and specific elongation of glass fibers reinforced PEEK at room temperature, 77 K and 20 K have been compared. And the fracture morphologies of different samples were investigated by scanning electron microscopy (SEM). The results showed a dependence of mechanical properties of glass fibers reinforced PEEK composites on temperature. The coefficient of thermal expansion of unfilled PEEK and glass fibers reinforced PEEK were also investigated from 77 K to room temperature. The results indicated that the thermal expansion coefficient (CTE) of PEEK matrix was nearly a constant in this temperature region, and it can be significantly decreased by adding glass fibers.