• recycling
• polymer mechanical testing
• Diels-Alder
• reversible thermosets

Thermo-reversible polymer networks are aimed to combine many mechanical properties of thermosets with the processability and recyclability of thermoplastics, with the added value of self healing properties. The Diels-Alder (DA) equilibrium represents the most promising approach to introduce reversibility in into polymer network. In this work three furan-modified polymers were combined into binary blends and then crosslinked with an aromatic bismaleimide through DA chemistry in order to extend their mechanical properties.
Notably, in Chapter 1 a furan functionalized ethylene-propylene rubber (EPM-Fu) was blended (up to 20%) with a furan functionalized polyketone (PK-Fu) and crosslinked. FT-IR and DSC analyses proved the reversible interaction between PK-Fu and EPM-Fu with the bismaleimide. Likewise, thermo-mechanical experiments (DMTA) indicated the re-workability of the material with no evident differences in elastic and loss modulus after several heating cycles and recycling procedures. A two-fold increase in Izod impact strength compared to the neat crosslinked polyketone was also recorded proving the toughening effect of the rubber. Analogously, in Chapter 2 the EPM-Fu rubber was blended with a furan modified biobased polyester and crosslinked. Thermal and mechanical reversibility, recyclability were proven by DSC and DMTA. A considerable toughening effect of the rubber was recorded, with negligible effect on the mechanical properties of the material. In Chapter 3 polyketones with different degree of furan modification were blended the EPM-Fu (up to 10%) and crosslinked. Reversibility was proven by DMTA. Swelling tests showed that higher furan intakes of PK-Fu lead to higher crosslink densities. Mechanical properties as Young modulus, compression set, hardness were determined and found to monotonously increase with the crosslink density.