Elastomer materials
featuring covalent cross-links deliver essential
elastic performance for various applications. Despite their benefits,
challenges like the need for toxic chemical additives, emissions of
harmful vapors, and difficulties in recycling these materials continue
to pose environmental and health concerns. Vitrimers emerge as an
option, allowing the recyclability of vulcanized elastomers through
the use of dynamic covalent bonds. However, for these to occur, it
is generally necessary to use toxic external catalysts, which generate
negative side effects on the material and cause environmental problems.
In this study, we propose a novel approach to address these challenges
by incorporating dynamic covalent bonds into ethylene-glycidyl methacrylate
(E-GMA)/zinc ionomer (EMAZn) blends, yielding catalyst-free vitrimers.
Notably, the zinc in the ionomer acts similar to a transesterification
catalyst, facilitating the material’s adaptability without
additional chemicals. Through a series of reactions including esterification
and subsequent transesterification, the E-GMA/EMAZn blends are transformed
into vitrimers capable of rearranging their topological structure
at elevated temperatures. This endows the vitrimers with recyclability
and reshaping abilities, all without the need for an external catalyst,
making them environmentally favorable, practical, and scalable. Utilizing
two commercially produced polymers on a large scale ensures cost-effectiveness
and avoids the need for slow and expensive chemical processes. Methodologically,
experiments were carried out to evaluate the properties of the prepared
vitrimers. Results revealed significant findings: stress relaxation
analysis demonstrated rapid adaptation to applied forces (G(t) < 100 s); cross-linking analysis
showed activation energies between 23.5 and 81 kJ/mol; self-healing
experiments achieved up to 94% recovery for the least cross-linked
blend; shape memory assessments exhibited a maximum recovery of 88%
and the ability to maintain multiple temporary shapes. Additionally,
recycling experiments confirmed the material’s feasibility
for sustainable reprocessing. This work presents a promising and sustainable
solution to the challenges associated with traditional rubber/elastomer
cross-linking methods, offering the potential for greener and more
efficient rubber materials.