Processing and properties of injection molded thermoplastic composites reinforced with melt processable glasses

This work was concerned with evaluating the properties of injection molded composites comprising polyetherimide (PEI) and polyetheretherketone (PEEK) reinforced with various lower T-g melt processable phosphate glasses. Composites were produced utilizing a variety of glass and resin combinations in order to ascertain the effects of factors such as glass concentration and viscosity of the components on the mechanical properties of the composite blends. Changes in the rheological and interfacial properties of the blends obtained by varying the resins and phosphate glasses used during processing resulted in a variety of reinforcing morphologies consisting of glass beads, ribbons, and an interpenetrating network structure. The large variations in the glass phase morphologies obtained during injection molding led to composites that displayed a wide range of properties. Generally, it was found that the use of resin/glass combinations that minimized the viscosity difference between the components resulted in composites displaying the best overall mechanical properties. The stiffness of the composites was found to increase with glass concentration with loadings up to 45 vol% glass, leading to moduli 3-4 times greater than those of the neat resins. While the addition of the phosphate glasses produced significant enhancements in the stiffness of the composite blends, the strength often fell to values 2-3 times lower than those of the neat resins.