ETD

• damage reporting
• DCNs
• Diels-Alder reaction
• dynamic covalent networks
• fluorophore
• mechanochromism
• perylene tetracarboxylic dianhydride
• polyketone
• PTCDA
• recyclable polymers
• SEBS
• self-healing polymers
• thermosets

The pervasive use of thermosetting polymers (TSPs) across demanding industrial sectors, driven by their superior mechanical properties, chemical inertness, and thermal stability, has created a critical paradox: their inherently stable and irreversible covalent structure translates into a significant environmental and economic burden at the end-of-life stage. To overcome this challenge, research has been strategically shifting towards the development of Dynamic Covalent Networks (DCNs), which are materials capable of undergoing reversible cross-linking, de-cross-linking, and thermal reprocessing.

The present Master’s thesis contributes to this essential research area by focusing on the design and synthesis of novel polymer networks that not only incorporate thermally-reversible self-healing properties but also seamlessly integrate the capability for autonomic damage reporting (mechanochromism).

The key innovation of this work lies in the development and utilization of a modified Perylene Tetracarboxylic DiAnhydride (PTCDA) derivative, which functions as a dual-functional dynamic linker. This highly conjugated molecule is engineered to serve two crucial roles simultaneously:

Dynamic Covalent Component: The PTCDA derivative is functionalized with maleimide groups and employed as the dienophile component in the reversible Diels-Alder (DA) / retro-Diels-Alder (rDA) cross-linking system. This reversible mechanism enables the covalent bonds to break and reform under thermal stimulus, granting the network self-healing and reprocessing capabilities.

Noncovalent Mechanochromic Sensor: The planar structure and intrinsic high fluorescence of the Perylene core allow the linker to act as an optical sensor. The material is designed to exhibit Aggregation-Caused Quenching (ACQ) mechanochromism, where mechanical stress (damage) triggers the reversible de-aggregation of the chromophores. This provides an immediate, low-force optical signal of stress accumulation, preceding catastrophic covalent bond failure.

The structural foundation of this research relies on two distinct polymer matrices, both functionalized with the furan diene component: a linear Polyketone (PK) and a SEBS-graft-Maleic Anhydride (MA) thermoplastic elastomer.

The final objective was the synthesis and comprehensive characterization of a fully integrated network, leveraging the synergy between the structural stability of the DA/Perylene system and the precise control offered by the optical monitoring. The synthesized systems were thoroughly characterized chemically, thermally, mechanically, and optically to confirm the cross-linking efficiency, validate the self-healing performance, and quantify the mechanochromic response. This research aims to establish a new benchmark for sustainable and smart materials, significantly extending the lifespan and reliability of the final products.