Dimer fatty acid-modified poly[ester-b-ether]s:: Synthesis and properties

Thermoplastic elastomers of the poly[ester-b-ether] copolymer type (PEE) comprising a hard block of poly(butylene terephthalate) (PBT) and oligoether soft segments, differing in the molecular weight of the oligoether [alpha,omega-dihydroxy poly(oxytetramethylene) (PTMO); M-n = 650, 1000, and 2900 g/mol] were synthesized and analyzed. Synthesized PEEs were modified by a dimer fatty acid (DFA, M-n = 570 g/mol) as a component of the soft segments. Each copolymer (consisting of one hard-segment component and two components of the soft segments) was obtained in a two-stage process involving transesterification and polycondensation in the melt. Elastomer series were prepared with a constant PET mass ratio of 50; the content of PTMO and DFA segments was changed. Differential scanning colorimetry results showed a single glass transition temperature for the mixed PTMO-DFA soft phase, which indicates that ether and aliphatic units are able to create a homogenous amorphous phase.