Unidirectional Carbon Fiber Reinforced Cyanate‐Based Shape Polymer Composite with Variable Stiffness

Cyanate‐based shape memory polymer (CSMP) has the advantages of good mechanical properties and excellent shape memory properties. However, the mechanical properties of polymers are relatively poor at high temperature. This article aims to improve the mechanical properties of CSMP by adding varying contents of unidirectional carbon fibers. The carbon fiber reinforced CSMP composites (CSMPCs) are prepared by vacuum hot pressing of prepregs. Compared with CSMP, the tensile, flexural, and compressive properties of the CSMPCs have significant improvement. By changing fiber content and adjusting temperature, the composites can achieve variable stiffness characteristic. In addition, the CSMPC with fiber content of 15% has excellent shape memory performances including higher recovery rates and faster recovery speeds. A shape memory spring based on CSMPC has strong deformation ability, which can realize large compression and stretching deformation. The CSMPCs make up for the shortcoming of decreased mechanical properties at high temperatures of CSMPs and broaden the application used in high‐temperature environments.