Fig. 1. Previous literature and this work.

a Comparison of previous literature on the synthesis of poly(isosorbide succinate) (PIsSu)^{9,11,12,29–35}. b Previous strategies to improve molecular weights of isosorbide-based polyesters^16,24,36. c The synthesis strategy of this work. Not shown in b is a strategy reported by Kricheldorf et al.³⁷. on the improvement of isosorbide-based polyester molecular weights via silylation of isosorbide’s-OH groups and subsequent reaction with diacid chlorides. Please note that only one regioisomeric combination of isosorbide repeat units is depicted in the polymer structures. The chirality of isosorbide will result in a polymer with a number of possible arrangements that do not necessarily possess tacticity.