Synthesis, Dynamic Mechanical Properties, and Shape Memory Effect of Poly(benzoxazine‐ether‐urethane)s

Abstract

Two series of poly(benzoxazine‐ether‐urethane)s (PBEUs) are prepared through thermally activated ring‐opening polymerization (ROP) of bi‐functional benzoxazines containing ether‐urethane moieties. The bi‐functional benzoxazines are synthesized through coupling reaction of hydroxyl‐containing mono‐functional monomers based on phenol, o‐allylphenol, o‐cresol, p‐cresol, diglycolamine, and paraformaldehyde with 1,6‐hexamethylene diisocyanate (HDI) and 2,4‐toluene diisocyanate (TDI), respectively. The ROP temperature of each HDI‐based benzoxazine is higher than that of the counterpart based on TDI, and they are in descending order ortho‐, para‐, and unsubstituted phenol for both series. Due to the difference in structure symmetry between the two series monomers, the variation of polymerization rate with temperature of each TDI‐based benzoxazine is different from that of the counterpart based on HDI. The ortho‐ and para‐substituted‐phenol‐based PBEUs show lower glass transition temperatures than that of the phenol‐based counterpart. In the vicinity of the glass transition temperature, the HDI‐based PBEUs exhibit thermally induced one‐way dual‐shape memory effect.

High‐Performance Vitrimeric Benzoxazines for Sustainable Advanced Materials: Design, Synthesis, and Applications

“…[222] There are currently several review articles and book chapters on advances in polybenzoxazine research. [153,[223][224][225][226][227][228][229][230][231][232][233][234][235][236][237][238][239] Benzoxazines are investigated for improved thermomechanical performance with much focus on smart functionalities, such as self-healing , [240] which can occur by the Friedel-Craft reaction, [241] photo-induced coumarin dimerization, [242] supramolecular hydrogen bonding, [243,244] ketene chemistry, [245] metal-ligand interactions, [246] or dynamic sulfide linkages; [13] shape memory; [132,150,152,243,[246][247][248][249][250][251][252][253] as well as antifouling protection, [254] and reprocessability. [13,159,255,256] Polybenzoxazines were reprocessed by simple dynamic sulfide linkages enabled by chopping into pieces and thermal treatment…”