Responsive sustainable and biodegradable systems based on Diels-Alder reaction from amylomaize starch

Abstract

Amylomaize starch (AMS) and poly(butylene adipate-co-terephthalate) (PBAT), a biodegradable and potentially biobased copolyester, were chemically modified to develop a thermally reversible network based on reversible Diels-Alder (DA) reaction between maleimide and furan groups. AMS was esterified with 6-maleimidohexanoyl chloride to obtain AMS–maleimide, as evidenced by FTIR, 1H, 13C and 2D NMR spectroscopies. PBAT was transesterified with 1,4–butanediol to yield PBAT oligomers-based diols (oligoPBAT-diol), to then react with furfuryl isocyanate to obtain oligoPBAT-difuran. The structures of PBAT derivatives were precisely determined by FTIR, 1H, 13C, 31P and 2D NMR spectroscopies and SEC. AMS-maleimide and oligoPBAT-difuran have then undergone a cycloaddition by DA reaction. The final products were analyzed by FTIR spectroscopy and modulated DSC, which showed the occurrence of retro DA. Overall, this study reports the high potential of this thermally responsive smart system to counteract the well-known incompatibility between starch and PBAT within multiphase materials and to develop performing materials for a circular bioeconomy.