Prepreg is a composite material intermediate consisting of a reinforcing material (such as fibers) and an uncured resin matrix. Its classification is primarily based on the following two criteria:
Classification by Matrix Material
Thermoset Prepreg:** Utilizes resins such as epoxy or phenolic as the matrix; once cured, the process is irreversible. For example, epoxy prepreg-commonly used in the aerospace sector (e.g., Hexcel's M21 series)-typically cures at temperatures ranging from 120°C to 180°C and can achieve a tensile strength exceeding 800 MPa (Source: Hexcel Technical Handbook).
Thermoplastic Prepreg: Utilizes polymers such as PEEK or PEKK as the matrix; it can be repeatedly heated and reshaped. For instance, PEEK prepreg-employed in automotive lightweighting applications-exhibits high-temperature resistance up to 250°C (Source: Solvay Report).
Classification by Reinforcing Material
Carbon Fiber Prepreg: Characterized by high strength and high modulus; widely used in aircraft structural components (e.g., the wings of the Boeing 787).
Glass Fiber Prepreg: Offers low cost and excellent electrical insulation properties; frequently used in wind turbine blades.
Aramid Fiber Prepreg: Possesses strong impact resistance; predominantly used in ballistic armor applications.
