Reinforced Supramolecular Networks of End Functionalized Polymers for Tailored Thermomechanical Property Profiles

Thermoset rubbers give rise to elastomers with tunable stiffness and high resilience but are not recyclable. Thermoplastic elastomers can address this problem but their broad applicability is impeded by either limited operating temperatures or inferior elasticity. Some supramolecular networks based on specific reversible non-covalent interactions are advantageous in this regard but typically remain restricted to low molecular weight polymers, because end group self-assembly becomes inefficient in high-molecular-weight polymers, which would in turn be required to yield resilient materials at high strains in tension. The present PhD project, therefore, aims to improve the efficiency of end group self-assembly independently of polymer molecular weight. To this end, mixtures will be prepared from polymers end-functionalized with self-assembling units that can form one-dimensionally extended aggregates with low-molecular-weight additives based on the same self-assembling motif. As a consequence, the polymer end groups and additives can co-assemble, so that the concentration of the self-assembling units can be varied independently of the molecular weight of the polymer, resulting in an efficient self-assembly into stable aggregates with high dissociation temperatures even for high-molecular-weight polymers. The research plan envisions the synthesis and preparation of the materials based on a range of different polymers and self-assembling units; the investigation of the structure of the self-assembled aggregates on different length scales; the characterization of thermomechanical, rheological, and tensile properties of the obtained materials; developing a thermodynamic model to prove the universality of the concept; and finally the preparation of blends of the different polymers functionalized with the same assembling moiety to obtain materials with novel and unusual property profiles.