A rheological and spectroscopic study on the kinetics of self-healing in a single-component diels-alder copolymer and its underlying chemical reaction

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2014-06, Vol.52 (12), p.1669-1675
• Main Authors: Bose, Ranjita K., Kötteritzsch, Julia, Garcia, Santiago J., Hager, Martin D., Schubert, Ulrich S., van der Zwaag, Sybrand
• Format: Article
• Language: English
• Subjects: Applied sciences; Copolymers; Diels-Alder polymers; Exact sciences and technology; Fourier transforms; FT-IR; Furans; Healing; microscratch testing; Organic polymers; Physicochemistry of polymers; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Recovery; Rheological properties; rheology; self-healing; Spectroscopy; Viscoelasticity
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.27164

ABSTRACT In this work, pendant groups with both furan and maleimide moieties were incorporated into a polymethacrylate copolymer with lauryl methacrylate as comonomer to yield a one‐system Diels–Alder (DA) polymer. A combined Fourier transform infrared (FTIR) spectroscopy and rheological study was performed to quantify the extent of the reversible DA reaction and the resulting changes in mechanical properties of the polymer. The kinetics of the retro‐Diels–Alder (rDA) reaction was studied at different temperatures to determine an enthalpy of activation. Control polymers with only one functional moiety, that is, the furan or maleimide, were also synthesized to study the differences in viscoelastic behavior and the absence of self‐healing. Microscratch tests were performed to obtain information about the disappearance of well‐defined intentional surface scratches under different healing conditions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1669–1675 Self‐healing polymers based on reversible Diels–Alder chemistry were synthesized along with nonhealing control polymers. A combined FTIR and rheological study showed that reversible crosslinking of the network can be achieved, which was linked to bulk microscratch healing. The use of nonhealing control samples did show some viscoelastic recovery but lacked chemical reversibility. Therefore, care must be taken to distinguish molecular healing from viscoelastic recovery; this can be achieved by combined spectroscopic and mechanical investigations.