Reworkable Polyhydroxyurethane Films with Reversible Acetal Networks Obtained from Multifunctional Six-Membered Cyclic Carbonates.

Multifunctional 6-membered cyclic carbonates (6-CCs) comprising acetal structures have been synthesized via phosgene-free routes and utilized for the fabrication of reworkable networked poly(acetal-hydroxyurethane) (PAHU) films. Dibenzoyl-protected di(trimethylolpropane) (DTMP) reacts with multifunctional aldehydes derived from nonexpensive alcohols to afford protected multifunctional DTMPs. After deprotection, the multifunctional DTMPs can react with diphenyl carbonate to efficiently form multifunctional 6-CCs. The polyaddition of the 6-CCs and diamines effectively proceeds in DMF to give networked PAHU films with good transparency and flexibility. These films possess the reworkability based on acid-catalyzed reversibility of acetal linkages. In particular, the film fabricated using large amounts of hexa-functional 6-CCs can reform reproducibly with maintaining to some degree its mechanical properties.