Poly(ethylene furanoate) modified with dimerized fatty acid diol towards multiblock copolymers: Microstructure - Property relationship

In this study we report on the effect of the chemical modification of poly(ethylene furanoate) (PEF) with dimerized fatty acid diol (FADD) towards the multiblock copolymer structure. PEF is currently an extensively investigated bio-based polyester, and further research to extend its applications, also towards PEF copolymers, are under intensive development. FADD is also fully bio-based, amorphous and highly flexible, what make it suitable as the copolymer soft segment. A series of PEF-block-FADD copolymers varied in rigid (PEF) to flexible (FADD) segments' ratio were synthesized via melt polycondensation under the relatively mild process conditions and a reasonable excess of diol, processed via injection molding, and characterized in regard of their chemical composition, thermal transitions and resulting microstructure, thermal stability as well as the mechanical performance including elastic deformability. The obtained results confirmed a multiblocked structure of the copolymers, their semicrystalline nature, and ability to separate for phases, but due to extremely low crystallization rate of the PEF segments the resulting microstructure is strongly dependent on the thermal treatment. In general the PEF/FADD copolymers reveal significantly modified mechanical parameters if compared to PEF, but also the features of thermoplastic elastomers.