Thermoplastic composites are produced using thermoplastic polymers as matrix materials, which soften upon heating to elevated temperatures for processing, and harden upon cooling. High-performance thermoplastic polymers used for thermoplastic composites provide a number of benefits compared to traditional thermoset resins, such as epoxies, including higher service temperature capability, lower moisture uptake, improved toughness, and increased chemical resistance.
Thermoplastic composites can also be reheated and reformed, providing benefits for manufacturing processes such as thermoforming and various thermal fusion/welding/joining processes. Unlike thermoset materials, thermoplastic composites do not require a chemical reaction or “cure,” and can be processed with much shorter molding cycle times. In addition, thermoplastic materials do not require refrigeration and have unlimited shelf life to further simplify and streamline the overall manufacturing process.
Thermoplastic composites typically use glass, carbon, or aramid fibers as reinforcement for the thermoplastic polymer matrix:
- Glass fibers – used in a wide range of structural and mechanical parts; improve most mechanical properties, including strength and stiffness; non-conductive; provides dimensional stability
- Carbon fibers – best strength and stiffness performance; lower density than glass; low coefficient of expansion; improved creep and wear resistance
- Aramid fibers – low coefficient of friction and thermal expansion; very good toughness; excellent wear and abrasion resistance
These reinforcements can also provide various benefits based on their physical configuration. For example, carbon fibers can be produced in continuous and discontinuous strands, and even flakes, each of which creates different properties in the finished product and allows use of different manufacturing processes. This design versatility allows thermoplastic composite materials to be developed for a wide range of use conditions.
Thermoplastic composites have become a viable alternative to metal assemblies, die castings, and traditional thermoset composite materials in the aerospace/defense and automotive industries, and in consumer goods and electronics. For example, rising fuel costs have compelled the aerospace industry to increase the use of thermoplastic composites in the manufacture of lightweight metal replacement components that were not previously cost effective with traditional thermoset materials.
Features and benefits of high-performance thermoplastic composites:
- Weight savings, fatigue performance, and corrosion resistance vs. metals
- Cost-effective manufacturing with reduced waste
- X-ray transparency (radiolucent)
- Improved damping vs. thermosets or metals
- Excellent toughness
- Low moisture uptake, providing very good hot-wet properties
- Excellent chemical resistance
- Excellent fire performance
- High service temperature capability