Shape memory polymers (SMPs) with elevated switching temperatures and enduring thermal properties are highly desirable yet challenging in certain aerospace applications. In this study, high-temperature shape memory phthalonitrile resins (SMPNs) were developed using an end-capping strategy with the uniphthalonitrile (UPN) as the end-capping reagent to modulate the density of the cross-linked network. The resultant SMPNs exhibit a glass transition temperature (Tg) at approximately 300 degrees C, with a shape fixation rate of about 98 % and a shape recovery rate around 97 %. Importantly, these SMPNs also demonstrated exceptional thermal stability, with a thermal decomposition temperature exceeding 445 degrees C. Additionally, an oxyacetylene ablative test revealed the SMPNs ' robust ablative resistance, as the linear ablation rate remained below 0.1 mm/s and the mass ablation rate was less than 0.1 g/s. The commendable shape memory performance and superior high-temperature resistance allowed the SMPNs to successfully undergo the shape recovery process when subjected to a butane flame. Furthermore, after a high-temperature annealing process, the SMPNs exhibited electrical conductivity due to graphitization, even possessing wave-absorbing properties within a specific frequency range. It is foreseeable that these multifunctional SMPNs will have extensive applications in the aerospace sector, given the advancement of smart structures.

CHEMICAL ENGINEERING JOURNAL  489 (2024)150956

Hu, Rongxiang; Zhang, Fenghua; Luo, Lan; Wang, Linlin; Liu, Yanju; Leng, Jinsong

https://doi.org/10.1016/j.cej.2024.150956

An end-capping strategy for shape memory phthalonitrile resins via annealing enables conductivity and wave-absorption.pdf