Thermoresponsive crosslinked isocyanate‐free polyurethanes by Diels‐Alder polymerization

Abstract

International audienc

Self‐healing semi‐IPN materials from epoxy resin by solvent‐free furan–maleimide Diels–Alder polymerization

“…In the rDA reaction thermogram of the polyadduct (sample DF 00:100), two endothermic transitions are appeared corresponding to the exo ‐adduct (thermodynamic product) and endo ‐adduct (kinetic product) stereoisomer, related to the steric orientation of maleimide and furan rings in the course of the DA cycloaddition reaction. Generally, exo ‐adduct is more stable than endo ‐adduct and appeared in higher temperature …”

“…In the DA reaction, through a [4 + 2] cycloaddition reaction between an electron‐rich diene and an electron‐poor dienophile, new dynamic covalent bonds are formed . Diene and dienophile react and give the so‐called adduct in generally two endo and exo steric isomers . Due to the exothermic nature of DA reaction, equilibrium state strongly depends on the temperature as an external stimulus.…”

Polymers Based on Cyclic Carbonates as Trait d'Union Between Polymer Chemistry and Sustainable CO2 Utilization

“…Polymeric compounds are also generally present (the structures in Figure 4a re representativeso ft he dimericc ompounds). [157] 4x was prepared startingf rom the careful glycidylation (using TBABa s ap hase-transfer catalyst) of furfuryl amine (a product of the reductive amination of furfuryl alcohol with ammonia; Scheme16) [158] to avoid cross-linking on the epoxide. [156] 4v was reacted with renewable diamines for the synthesis of PHU networks with high renewable content.…”

“…[147] In principle, this method could also be appliedt ot ransesterifications with GD or GC (Scheme 23 d). [83,105,120,133,134,147,157,167,175,184] For more challenging internal epoxides,e ven harsher reaction conditions, [106,181] the use of supercritical CO 2 ,a nd/orl ong reaction times (up to 4-7 d) have been reported. [210] The use of supported Mo, Ti,T a, or Wc atalysts in the presence of potentially renewable H 2 O 2 as oxidant (Scheme23f)i su nder investigation as ag reener method for the epoxidation of olefinicc ompounds such as fatty acids and vegetableo ils that are precursorsi nt he synthesis of bio-based carbonates.…”

Advances in intrinsic self-healing polyurethanes and related composites

“…As a promising example, Caillol et al have developed thermoreversible and reprocessable nonisocyanate based PUs. Furfuryl glycidyl ether was therein converted into cyclocarbonate derivative and mixed with dimaleimide-terminated polypropylene glycol and a diamine, forming a thermomendable networks 140,141. Delpierre et al herein described a simple approach to design a nonisocyanatebased PU network featuring multi-responsiveness to humidity and temperature and outstanding healing properties by combining iminoboronate and boroxine chemistry(Fig.…”