Unsaturated 2‐oxazoline end capping of liquid crystalline polyester by reactive processing and in a solution

Abstract

End capping of liquid crystalline poly(ethylene terephthalate-co-oxybenzoate) with a bifunctional 2-oxazoline derivative, 2-(4-allyloxyphenyl)-2-oxazoline, has been performed in melt under the condition of reactive processing and in a solution. The reaction in melt is very fast and, despite some modifier evaporation, it is completed in 2 min at 230°C. The product is a polyester containing unsaturated end groups bonded via esteramide linkage. The presence of unsaturation was proved by 13 C-NMR spectroscopy. An increase in temperature and prolongation of the processing time gives raise to thermal-induced reactions on the unsaturated end groups, resulting in an increase of the glass transition temperature. Depending on the processing temperature decomposition, propagation and crosslinking occur in different extent and influence polymer properties.

Ex Vivo and In Vitro Studies on the Cytotoxicity and Immunomodulative Properties of Poly(2‐isopropenyl‐2‐oxazoline) as a New Type of Biomedical Polymer

“…An addition reaction can be performed in the melt under reactive processing or solution conditions. These reactions can also be used in polymerization processes to modify polymers, for chain‐extension or for crosslinking . Polymerization of bis(2‐oxazolines) with dicarboxylic acids provides poly(ester amide)s with a different structure .…”

Synthesis, kinetics, and characterization of bio-based thermosets obtained through polymerization of a 2,5-furandicarboxylic acid-based bis(2-oxazoline) with sebacic acid

“…15 Besides, bis(2-oxazoline) monomers have been used for chain extension of polymers and end-capping or modification of polymers and for introducing functionalities along the polymer backbone. [16][17][18][19] Especially thermally initiated melt polymerizations or chain extension reactions are of interest for industrial purposes, due to the absence of solvents and solvent recovery systems. Interestingly, besides the synthesis of linear polymer chains, these melt-polymerizations allow for the production of cross-linked polymers in one reaction step.…”

Impact of the chain extension of poly(ethylene terephthalate) with 1,3‐phenylene‐bis‐oxazoline and N,N′‐carbonylbiscaprolactam by reactive extrusion on its properties

“…In the case of PET, the reaction with the carboxylic acid end groups is the most important one. The reaction of carboxyl acid groups with oxazolines results in the formation of ester amide bonds, and many applications are generated with the aid of this type of reaction . In Scheme , the chain extension reaction of 1,3‐PBO with the carboxyl end groups of PET is presented.…”