Polyphthalamide is a high-performance resin with exceptional thermal, mechanical, and physical properties. It is hygroscopic, opaque, semicrystalline, and can be used in plastic injection molding. Most PPA are filled with glass fiber or carbon fiber to enhance stiffness for high-temperature applications. As a result, PPA is often used in applications in place of metal or higher-priced thermoplastic.

PLA is a high-strength but brittle plastic that cannot be used in applications that experience shock loads. The lactic acid building blocks of PLA can be made from fermented plant starch, like corn, under controlled conditions. It takes less energy to produce PLA than petroleum-based thermoplastics, making it relatively eco-friendly. PLA is often regarded as being biodegradable.