Healable network polymers bearing flexible poly(lauryl methacrylate) chains via thermo‐reversible furan‐maleimide diels–alder reaction

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2017-08, Vol.55 (16), p.2700-2712
• Main Authors: Patil, Sachin S., Torris, Arun, Wadgaonkar, Prakash P.
• Format: Article
• Language: English
• Subjects: atom transfer radical polymerization; Chain mobility; Chains (polymeric); Chemical synthesis; Cooling; Diels-Alder reactions; Diels–Alder polymers; Ethane; furan‐maleimide click reaction; Glutamic acid; Healing; Heating; Loss modulus; macromonomers; Molecular structure; Molecular weight; Polymerization; Polymers; Storage modulus; thermo‐reversible network polymers
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.28677

ABSTRACT 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 bisfuryl‐terminated PLMA with 1,1′,1″‐(nitrilotris(ethane‐2,1‐diyl))tris(1H‐pyrrole‐2,5‐dione). The prepared network polymer showed retro‐Diels–Alder reaction in the temperature range 110–170 °C as determined from DSC analysis. The presence of low Tg (–40 °C) PLMA chains induced chain mobility to the network structure which led to the complete scratch healing of the coating at 60 °C in five days due to furan‐maleimide adduct formation. The storage modulus of the network polymer was found to be 3.7 × 104 Pa at the constant angular frequency of 5 rad/sec and strain of 0.5%. The regular reversal of storage (G′) and loss modulus (G″) was observed with repeated heating (40 to 110 °C) and cooling cycles (110 to 40 °C) at constant angular frequency and strain. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2700–2712 Thermo‐reversible network polymer bearing flexible poly(lauryl methacrylate) (PLMA) chains was designed and synthesized via furan‐maleimide Diels–Alder click reaction of bisfuryl‐terminated PLMA macromonomer with 1,1′,1″‐(nitrilotris(ethane‐2,1‐diyl))tris (1H‐pyrrole‐2,5‐dione). The network polymer exhibited complete scratch healing at 60 °C, thanks to the presence of flexible PLMA chains which induced the chain mobility in these systems due to their low Tg (–40 °C).