High-performance chlorinated polyvinyl chloride/polyurea nanocomposite foam with excellent solvent resistance, flame-triggered shape memory effect and its upcycling

•Excellent fire-resistance CPVC/PUA nanocomposite foam was prepared by the PFR strategy combining with catalytic carbonization.•CPVC/PUA nanocomposite foam exhibits excellent comprehensive performance due to the unique microphase separation structure in cell walls.•The urea group in PUA as a hydrogen bond donor effectively promotes the dehydrochlorination and cross-linking carbonization of CPVC.•The CPVC/PUA nanocomposite foams can be directly upcycled into functional carbon foams.