Synthesis and thermal analysis of branched and ?kinked? poly(ethylene terephthalate)

Decoding Polymer Architecture Effect on Ion Clustering, Chain Dynamics, and Ionic Conductivity in Polymer Electrolytes

“…The glass-transition and melting temperatures of the neat (salt-free) PEOs for various architectures ranged around −55 and 60 °C, respectively (the representative DSC thermographs for the melting and glass-transition behaviors are given in Figure S2; see the DSC results in the Supporting Information for the details of DSC thermographs obtained for all PEO topologies). No significant change in T g is observed for the salt-free PEO, in agreement with the previous reports. − T m , however, was more architecture-dependent such that the nonlinear chain architectures usually display lower melting temperatures (with a shift in T m as high as 20 K). Also, T m decreases with decreasing arm molecular weight of star PEOs for the same functionality.…”

Crystallisation kinetics of novel branched poly(ethylene terephthalate): a small‐angle X‐ray scattering study

“…Compared to the unprocessed PET, the control and branched PETs required less energy to overcome the activation barrier for crystallisation from the amorphous glassy state, although the enthalpies ( H cc ) were comparable. Similar behaviour was observed by Jayakannan and Ramakrishnan 10,31 with branched PET formed during polycondensation, but unlike the present study, they also observed a decrease in T g , most likely due to a concurrent decrease in the molecular weight. The branched PET exhibited a lower melt temperature (T m ), typical of greater heterogeneity in crystal sizes and increased imperfections due to branching sites disrupting chain packing.…”

Effect of branching on the thermal properties of novel branched poly(4-ethyleneoxy benzoate)

“…This difference in reactivity could be attributed to the presence of an electron‐donating alkoxy group in the para‐position in E4HEB that made the ester carbonyl less susceptible to nucleophilic attack when compared to that in EBHEB. A similar observation was made previously in a comparison of the reactivities of p and m isomers toward copolymerizations in PET copolymers 9.…”

“…A plot of Δ H m versus the extent of branching is shown in Figure 4. It is clear from this plot that the percent crystallinity of the copolymers came down drastically with the incorporation of branching, something we also observed in an earlier study on PET 9, 10. Similarly, the plot in Figure 5 depicts the variation of T c , which reflects the peak temperature during the cold crystallization of the rapidly quenched amorphous polymer samples, with branching.…”

“…In our PEOB‐B x samples, although the T g / T m ratio ranged from 0.72 to 0.76 (see Table II), the T g passed through a minimum. Similarly, in the case of lightly branched PET, a significant drop in the T g at low levels of branching indeed was observed, although in this case the ratio T g / T m was about 0.67 for PET with 5% branching 9. It appears, therefore, that this unusual variation may not be related to the ratio T g / T m but instead to the other factors that were expounded earlier.…”