Stereodynamic control of star-epoxy/anhydride crosslinking actuated by liquid-crystalline phase transitions.

Pin, Jean-Mathieu; Mija, Alice; Sbirrazzuoli, Nicolas · Soft Matter · 2017

basic_science · Level V

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Abstract

The epoxy/anhydride copolymerization kinetics of an original star-epoxy monomer (TriaEP) was explored in dynamic heating mode using a series of isoconversional methods. Negative values of the apparent activation energy (E<sub>α</sub>) related to an anti-Arrhenius behavior were observed. The transition from Arrhenius to anti-Arrhenius behavior and vice versa depending on the E<sub>α</sub> of polymerization was correlated with the dynamics of mesophasic fall-in/fall-out events, physically induced transition (PIT) and chemically induced transition (CIT). This self-assembly phenomenon induces the generation of an anisotropic crosslinked architecture exhibiting both nematic discotic (N<sub>D</sub>) and nematic columnar (N<sub>C</sub>) organization. Particular emphasis was placed on evaluating the juxtaposition/contribution of the liquid-crystalline transitions to crosslinking, considering both the reaction dynamics and the macromolecular vision.