Healable Network Polymers Bearing Flexible Poly(Lauryl Methacrylate) Chains via Thermo-Reversible Furan-Maleimide Diels-Alder Reaction

A new ATRP initiator containing two furyl rings, namely, bis(furan-2-ylmethyl) 2-bromopentanedioate was synthesized starting from commercially available L-glutamic acid as a precursor. Well-defined bisfuryl-terminated poly(lauryl methacrylate) macromonomers with molecular weight and dispersity in the range 5000-12,000 g mol(-1) and 1.30-1.37, respectively, were synthesized employing the initiator by atom transfer radical polymerization (ATRP). Independently, 1,1',1"(nitrilotris(ethane-2,1-diyl)) tris(1H-pyrrole-2,5-dione) was synthesized as a tris-maleimide counterpart for furan-maleimide click reaction. Thermo-reversible network polymer bearing flexible poly(lauryl methacrylate; (PLMA) chains was obtained by furan-maleimide Diels-Alder click reaction of bisfurylterminated PLMA with 1,1',1"-(nitrilotris(ethane-2,1-diyl)) tris(1Hpyrrole-2,5-dione). The prepared network polymer showed retro-Diels-Alder reaction in the temperature range 110-170 degrees C as determined from DSC analysis. The presence of low Tg (-40 degrees C) PLMA chains induced chain mobility to the network structure which led to the complete scratch healing of the coating at 60 degrees C in five days due to furan-maleimide adduct formation. The storage modulus of the network polymer was found to be 3.7 x 10(4) Pa at the constant angular frequency of 5 rad/ sec and strain of 0.5%. The regular reversal of storage (G0) and loss modulus (G") was observed with repeated heating (40 to 110 degrees C) and cooling cycles (110 to 40 degrees C) at constant angular frequency and strain. (C) 2017 Wiley Periodicals, Inc.