Biosourced All-Acrylic ABA Block Copolymers with Lactic Acid-Based Soft Phase
16 pags., 9 figs. ; Lactic acid is one of the key biobased chemical building blocks, given its readily availability from sugars through fermentation and facile conversion into a range of important chemical intermediates and polymers. Herein, well-defined rubbery polymers derived from butyl lactate solvent were successfully prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization of the corresponding monomeric acrylic derivative. Good control over molecular weight and molecular weight distribution was achieved in bulk using either monofunctional or bifunctional trithiocarbonate-type chain transfer agents. Subsequently, poly(butyl lactate acrylate), with a relative low Tg (-20 °C), good thermal stability (5% wt. loss at 340 °C) and low toxicity was evaluated as a sustainable middle block in all-acrylic ABA copolymers using isosorbide and vanillin-derived glassy polyacrylates as representative end blocks. Thermal, morphological and mechanical properties of copolymers containing hard segment contents of <20 wt% were evaluated to demonstrate the suitability of rubbery poly(alkyl lactate) building blocks for developing functional sustainable materials. Noteworthy, 180° peel adhesion measurements showed that the synthesized biosourced all-acrylic ABA copolymers possess competitive performance when compared with commercial pressure-sensitive tapes. ; This research was funded by Spanish Ministerio de Ciencia, Innovación y Universidades through project MAT2017-82669-R (to G.L. and J.C.R.), Serra Hunter Programme of the Government of Catalonia (to G.L.), University Rovira i Virgili (DL003536 grant to N.B.), Miguel Servet Program from Instituto de Salud Carlos III (CPII13/00017 to O.A.), Fondo de Investigaciones Sanitarias from Instituto de Salud Carlos III, and European Union (ERDF/ESF, 'Investing in your future') (PI18/00349 to O.A.), Diputación General de Aragón (Predoctoral Research Contract 2019 to A.J.-A., 'Digestive Pathology Group' B25_20R to O.A.), and Centro de Investigación Biomédica en Red en Enfermedades Hepáticas y Digestivas (CIBERehd). I.L. and L.V. gratefully acknowledge support from the European Regional Development Fund (No. MOBTT21), the Estonia-Russia Cross Border Cooperation Programme (ER30) and the Baltic Research Programme in Estonia (EEA grant no. EMP426)