CR-FOAM is a lightweight, high-strength closed-cell thermoplastic structural core material made from PET foam, combining excellent mechanical properties with good environmental durability. It not only significantly reduces the weight of composite components but also offers outstanding fatigue resistance, corrosion resistance, and aging resistance, making it suitable for demanding applications such as marine, wind energy, and transportation. Moreover, CR-FOAM features good process compatibility, allowing easy integration with various resin systems during composite manufacturing. The material is also recyclable, meeting the modern industry’s requirements for green and sustainable development. Therefore, CR-FOAM is regarded as an ideal composite core material for achieving lightweight construction and high reliability.