Interpenetrating Epoxy Networks Containing Diels-Alder Type Reversible Covalent Links: Shape-Constant and Self-Healing

by Dr., A.Strachota

October 22, 2025 ( 14:00 )

Lecture Hall CH3, Faculty of Science, Hlavova 8, Praha 2

Add to Calendar 10/22/2025 14:00 Europe/Prague Interpenetrating Epoxy Networks Containing Diels-Alder Type Reversible Covalent Links: Shape-Constant and Self-Healing

Covalent adaptive networks (CAN) are modern polymers, which offer numerous advanced applications, in the form of pure material or as a component, starting with re-processible rigid or rubbery thermostats, through self-healing materials, up to sophisticated programmable shape-memory systems. The development of self-healing materials for electrical insulation is essential for extending both the service life and the reliability of high-voltage components. Hence, in the presented work, novel epoxy resins with temperature-activated self-healing were designed, using the interpenetrating polymer network (IPN) approach. The prepared materials combine a permanently crosslinked epoxy-amine (EP) subnetwork with a thermo-reversible Diels-Alder (DA) subnetwork. The permanent EP structure provides mechanical- and shape stability, while the reversible DA component makes possible nearly complete restoration of properties, after previous fracture followed by healing treatment. The EP network was obtained by reacting diglycidyl ether of bisphenol A (DGEBA) with poly(propylene oxide)-α,ω-diamine (D) with different chain lengths of D, whereas the DA network was formed from a furan-tetra-functionalized derivative of "D" and the diphenylmethane-derived bismaleimide (BMI) and employed the reversible addition of maleimide to furan as the reversible crosslinking mechanism.

Rheological and dynamic-mechanical thermal (DMTA) analyses were employed to find optimal curing protocols, component ratios, and healing conditions. Systems with shortest "D" chains showed the best dielectric performance, while longer "D" minimized the occurrence of side reactions during synthesis and healing. The most promising balance between self-healing efficiency and insulating properties was achieved for the IPN system containing “D” with the size of 400 g/mol. Our results highlight the potential of DA-based IPNs in smart electrical insulation applications.

 Lecture Hall CH3, Faculty of Science, Hlavova 8, Praha 2

Covalent adaptive networks (CAN) are modern polymers, which offer numerous advanced applications, in the form of pure material or as a component, starting with re-processible rigid or rubbery thermostats, through self-healing materials, up to sophisticated programmable shape-memory systems. The development of self-healing materials for electrical insulation is essential for extending both the service life and the reliability of high-voltage components. Hence, in the presented work, novel epoxy resins with temperature-activated self-healing were designed, using the interpenetrating polymer network (IPN) approach. The prepared materials combine a permanently crosslinked epoxy-amine (EP) subnetwork with a thermo-reversible Diels-Alder (DA) subnetwork. The permanent EP structure provides mechanical- and shape stability, while the reversible DA component makes possible nearly complete restoration of properties, after previous fracture followed by healing treatment. The EP network was obtained by reacting diglycidyl ether of bisphenol A (DGEBA) with poly(propylene oxide)-α,ω-diamine (D) with different chain lengths of D, whereas the DA network was formed from a furan-tetra-functionalized derivative of "D" and the diphenylmethane-derived bismaleimide (BMI) and employed the reversible addition of maleimide to furan as the reversible crosslinking mechanism.

Rheological and dynamic-mechanical thermal (DMTA) analyses were employed to find optimal curing protocols, component ratios, and healing conditions. Systems with shortest "D" chains showed the best dielectric performance, while longer "D" minimized the occurrence of side reactions during synthesis and healing. The most promising balance between self-healing efficiency and insulating properties was achieved for the IPN system containing “D” with the size of 400 g/mol. Our results highlight the potential of DA-based IPNs in smart electrical insulation applications.