Modification of Epoxy Anhydride Systems Based on Epoxy Resin DER ‐330 With a Reactive Metathesis Poly(Anhydride of Norbornene Dicarboxylic Acid)

Poly(norbornene dicarboxylic anhydride) (PNDA) is introduced as a reactive modifier for epoxy‐anhydride systems. Laser microinterferometry reveals that PNDA dissolves in isomethyltetrahydrophthalic anhydride at 100°C and above, and chemically reacts with the epoxy oligomer DER‐330. DSC analysis shows that PNDA accelerates curing: T onset decreases from 112°C to 32°C–89°C and T peak decreases from 133°C to 105°C–126°C, depending on the modifier content and molecular weight. Viscosity measurements show that the polymer modifier increases the system's viscosity and reduces its gelation time at 100°C to 60 s. Modified systems exhibit a high glass transition temperature (up to 132°C according to DSC), retain optical transparency, and show improved mechanical and adhesive properties. The greatest strengthening is achieved with low‐molecular‐weight PNDA: flexural strength increases to 44.3 MPa, impact strength to 4.2 kJ m 2 , and adhesive shear strength to steel and caprolon reaches record values of 21.0 and 8.9 MPa, respectively. However, high loadings of high‐molecular‐weight PNDA lead to excessive viscosity and processing difficulties, resulting in a decrease in mechanical performance, which highlights the importance of optimizing both the molecular weight and concentration of the modifier.