Design and Synthesis of Shape Memory Phenol-Formaldehyde with Good Irradiation Resistance, Thermal, and Mechanical Properties

Phenol-formaldehyde (PF) resins with low flammability and excellent ablative property have been widely used in thermal protection systems in the aerospace field. The developing deployable thermal protection structure has prompted further exploration of the possibility of PF resin as a smart polymer. This paper prepares the shape memory phenol-formaldehyde resins (SMPFs) by introducing polyurethane (PU) prepolymer into the resol resin. The SMPFs with crystallization microregion possess excellent shape memory performance and better toughness than PF resin. In addition, the SMPFs have a higher carbon residue rate and better thermal stability compared with other shape memory polymers commonly used in the aerospace field. Multiple test results before and after γ-ray irradiation indicate that SMPFs have excellent irradiation resistance. The oxyacetylene ablative test demonstrates that SMPFs have relatively good ablative resistance. SMPFs inspire the production of intelligent thermal protection systems.