Effect of cross‐linking on the mechanical properties, degree of crystallinity and thermal stability of polyethylene vitrimers.

Maleic anhydride‐grafted‐polyethylene was dynamically cross‐linked via reactive melt blending with 4,4′‐dithiodianiline. Thermal and mechanical properties of polyethylene vitrimers with different cross‐linking density were investigated. The results indicate that the degree of crystallinity decreased with increasing cross‐linking density. This behavior was directly related to short‐term and long‐term mechanical properties: vitrimers showed a decrease in yield strength and creep performance. The yield strength of PE vitrimers decreased linearly in relation to the degree of crystallinity. Polarized optical microscopy revealed that the cross‐links inhibit the growth of spherulites structure in polyethylene vitrimers. Thermogravimetric analysis indicated an increase in the onset degradation temperature and decomposition rate for vitrimers with increased cross‐linking density. The stiffness of the vitrimers decreased with increasing cross‐linking density which led to higher damping properties. Finally, it was demonstrated that reprocessing of polyethylene vitrimer was possible without significant impact in mechanical properties. [ABSTRACT FROM AUTHOR]