Executive Summary : | The proposed project aims to enhance the applicability of dynamic covalent polymeric networks (DCPNs) by minimizing creep. It consists of two parts: developing a robust DCPN based on internal catalysis and trans-etherification (ICTE), and designing a general strategy for improving DCPN applicability. The ICTE-DCPN network will be synthesized by reacting di-arm benzyl ether with tri-arm alcohol, trimethylolpropane ethoxylate. The thermal, mechanical properties, and recyclability of the network will be examined using experimental tools like DSC, TGA, and VT-IR. The network will be chemically and mechanically recycled, with an excess of small molecule alcohol at higher temperatures to activate trans-etherification and break down the network to its starting materials. A molecular model system will be examined to understand the nature of internal catalysis pathways and network formation mechanism. A general design of DCPN is proposed, where at low temperatures, the crosslinkers are in a de-crosslinked state, while at higher temperatures, the network is more crosslinked. This inverse relationship between viscosity and flow is fundamentally interesting, and the viscosity of the material can be reversibly tuned. The boronic ester is selected as the dynamic functional group for the development of creep-resistant DCPN. The trans-esterification of the boronic ester derivative of cyclohexane diol with cyclopentanediol is employed for reversible crosslinking. The thermal, mechanical properties, and recyclability of the DCPN will be examined using DSC, TGA, and VT-IR. DMTA studies will be performed to investigate the thermomechanical properties of the network, including creep. |