Interchange Reactions in Condensation Polymers and Their Analysis by NMR Spectroscopy

Sequence Analysis of Polyether-Based Thermoplastic Polyurethane Elastomers by 13C NMR

“…It can be assessed from these values that the hydroxyl groups of BD and PTMG display similar reactivity. Otherwise, a blocky microstructure should be generated unless transurethanization reactions have taken place, which is largely unexpected at the temperatures used for the reaction. , …”

The Effect of Transreactions on the Structure and Dynamic Mechanical Properties of 1:1 Poly(ethylene terephthalate)/Poly(ethylene 2,6‐naphthalate) Blends Produced by Cryogenic Mechanical Alloying

“…Melt mixing of PET and PEN results in the formation of block copolymers by means of transesterification 1–19. Generally, transesterification reactions in molten blends of polyesters may advance via two various chemical pathways – inner‐inner or inner‐outer 25.…”

“…It has been well documented that PET/PEN blends are initially immiscible and tend to form separated phases 11. However, at extrusion temperatures of 270–300 °C and mixing times of 5–20 min certain amounts of PET‐PEN block copolymers are unavoidably produced by transesterification at the domains' interface 12. As stated by Stewart et al13 and many others, chemical interchange reactions result in blend compatibilization and the phase structure of the system changes, which has a strong impact on its optical and mechanical properties.…”

Straightforward Synthetic Protocol to Bio-Based Unsaturated Poly(ester amide)s from Itaconic Acid with Thixotropic Behavior

“…For this reason, preformed symmetrical diols that have two internal amide bonds were used for the synthesis of poly(ester amide)s. In order to assure that the amido diol structure would remain intact under the conditions applied for the synthesis, the dimethyl esters of the respective acids were used. Previous studies have shown that the amido diol structure can be lost by an acidolysis-type reaction if free carboxylic acid groups are present during reaction [43][44][45]. Hence, the dimethyl esters of dicarboxylic acids were utilized to avoid this undesirable side reaction.…”