Dielectric relaxation of poly(ester-ether-carbonate) multiblock terpolymers

The influence of low-concentration γ-Fe2O3 magnetic nanoparticles in a poly(ether–b–ester) copolymer matrix on interfacial polarization and glass transition

“…Such materials exhibit a phase-separated nanostructure with soft and hard phases architecture depending on the content of alternating flexible and rigid segments. The segmental dynamics of sequences and blocks of similar copolymers has been studied previously with the use of dielectric spectroscopy [14][15][16][17][18]. Dielectric relaxation measurements could provide information on the structure of polymer nanocomposite materials [16].…”

Relaxation Behavior of Poly(ester carbonate) Block Copolymer Across the Melting Region

“…[5,12] The above value is consistent with the assignment of the low temperature process to a local motion associated either with the ester group in PBT or with a combination of ester and carbonate groups in the PBT-PC copolymer. [9] The c-process can be well described by a symmetric (c = 1) HNfunction with a similar broadening b-value in all the investigated systems (Figure 9 (a)). At fixed temperature, the dielectric strength values (Figure 9 (b)) slightly increase with increasing PC block concentration as expected by the progressive decreasing of crystallinity which tends to increase the amount of dipoles in the amorphous phase involved in the relaxation.…”

“…[9,12] As shown in Figure 8, the relaxation time for this process follows an Arrhenius-type behavior with an activation energy of L45 kJ N mol -1 for all the investigated samples. Due to the fact that the reported activation energies for both carbonate and ester groups are very similar, it is difficult to distinguish between these processes in terms of their activation energies.…”

“…[9] Accordingly, the corresponding relaxation times follow a VFT temperature dependence ( Figure 8). The strong-fragile scheme proposed by Angell [23] allows one to classify glass-forming systems on the basis of the temperature dependence exhibited by the viscosity or the relaxation time of the equilibrium liquid.…”

Selected dielectric and relaxation properties of PBT-DFA multiblock elastomers

“…Relaxation properties of different multiblock copolymers were reported for polymers where the soft segments were composed of polyether blocks, such as poly(1,3-oxypropylene)diol or oligo(oxyethylene)diol [2,3] and poly(ether-carbonate). [4] Multiblock copolymers composed of polyaliphatic (here: dimerized fatty acid, DFA) soft blocks as soft segments were synthesized by randomly joining the DFA segments and hard poly(butylene terephthalate) (PBT) segments. [5] The chemical structure of such copolymers is presented in Scheme 1.…”