Structural deformation phenomenon of synthesized poly(isosorbide-1,4-cyclohexanedicarboxylate) in hot water

Abstract

Previously syntheses of poly(isosorbide 1,4-cyclohexanedicarboxylate) (PICD) have overcome synthetic problems associated with the low-reactivity of isosorbide, using acetic anhydride to achieve in situ acetylation. However, this amorphous polymer exhibits unusual behavior when submerged in water at 100 degrees C. Severe deformation occurs, with cylindrical pellets changing into a disc-like morphology, similar to solvent-induced crystallization. The influence of water on the thermal behavior of PICD was analyzed, resulting in a mechanism analogous to solvent-induced crystallization, where the solvent functions as a plasticizer. Furthermore, the effects of acetic anhydride and open-ring isosorbide on structural deformation were investigated, revealing the occurrence of ester hydrolysis. Finally, solid state CP-MAS C-13-NMR was used to elicit the rearrangement or packing of carbons within the PICD structure.