Deniz Yilmaz1* , Felix H. Schacher1,2,3
1Institute of Organic Chemistry and Macromolecular Chemistry (IOMC), Friedrich-Schiller-University Jena, Germany
2Jena Center for Soft Matter (JCSM), Friedrich-Schiller-University Jena, Germany
3Helmholtz Institute for Polymers in Energy Applications Jena (HIPOLE Jena), Germany
Many efforts in polymer science aim towards new materials by controlling stability and the state of suitable bonds. The introduction of crosslinks, physical or covalent, between polymer chains leads to the formation of polymer networks with unique properties. In comparison to polymer networks with permanent covalent crosslinks, networks with dynamic covalent crosslinks feature chain mobility and adaptivity to external triggers. This is frequently fused in the design of shape-memory, self-healing materials and stimuli-responsive polymer gels.1 It is desirable to transfer bond reversibility under ambient conditions also to the class of polyesters, rendering materials with tunable mechanical properties and often inherent degradability.
This project investigates the physical, thermal and morphological properties of the dynamic covalent networks derived from polycaprolactone-based copolyesters. These properties are examined via copolymers of caprolactone and either α-chloro-ε-caprolactone (αClεCL) or 1,4,8-trioxaspiro-[4.6]-9-undecanone (TOSUO) with crosslinkable chlorine and hydroxyl functionalities respectively. The dynamic covalent bond between the chains varies from a disulphide bridge to an imine bond concerning the chlorine and the hydroxyl functionality on the copolymer side-chain. The type of the dynamic bond in return, determines the stimuli such as light, pH or temperature with which bond reversibility occurs (Figure 1). Characterization techniques primarily include differential scanning calorimetry, thermo gravimetric analysis, small and wide-angle X-ray scattering, proton NMR spectroscopy and size exclusion chromatography.