Asymmetric Co-unit Inclusion in Statistical Copolyesters

• DOI: 10.1021/acs.macromol.0c01965
• Publication Date: 2021-01-04T18:04:39Z
• Authors: Mareen Schäfer; Shichen Yuan; Albrecht Petzold; Ricardo A. Pérez-...; Alejandro J. Müller; Thomas Thurn-Albr...; Kay Saalwächter; Klaus Schmidt-Rohr
• Keywords: Comonomer; Adipate; Small-angle X-ray scattering; Lamella (surface anatomy)

The biodegradation of isodimorphic random butanediol-succinate/adipate copolymers (PBSAs) can be affected by a change in the semicrystalline morphology. A crucial point for final structure is incorporation monomers minority component into crystals majority component. We use proton time-domain NMR and wide-angle X-ray scattering to characterize across their complete composition range analyze possible inclusion comonomers PBA-rich 20/80 PBS-rich 60/40 applying different solid-state 13C experiments. For copolymers, we find nearly constant volumetric crystallinity 50% up 50/50 combined with an increase crystalline lamella thickness. has detected BS units incorporated BA structure, where on average every tenth monomer comonomer. In crystals, crystallite thickness decrease from neat PBS PBSA 37% ∼20%, respectively. also evidence that are excluded bulk crystal but accumulate at surface. amount these pocket-like structures estimated 7–9% comonomer content.