We present an experimental investigation of the mechanical properties of solid vitrimer samples obtained by incorporating a diepoxide into a commercial PBT in the presence of a Zn(II) catalyst using batch compounder and injection molding machines. Tensile experiments were carried out at different temperatures (80°C, 120°C, 160°C) below the melting point (220°C) and with various diepoxide concentrations (0, 1, 2wt%,). We found that vitrimer plastic deformation mechanisms differ drastically from those of the PBT precursor, and more generally from the regular behaviour of other semi-crystalline polymers. In PBT vitrimers, strain localization (necking) is very weak and can even be suppressed. This type of behaviour is due to the increase in strain hardening caused by vitrimer crosslinking. The creep resistance and stiffness of PBT vitrimers are significantly higher than that those of the pristine PBT. We found that vitrimer modification of PBT at moderate levels improves dimensional stability without inducing brittleness. These promising results highlight the need to find processes which enable significant 2 production levels of these new materials. In the perspective section, we briefly present a way to produce PBTbased vitrimers using CRE (Continuous Reactive Extrusion).'' G ) moduli measured by rheometry with temperature or frequency sweeps. 6,13,27,30,37,[40][41] In particular, it is possible to roughly estimate whether a vitrimer has predominantly "rubber" ( ' '' GG  ) or "viscous" behaviour ( '' ' GG  ) for a given temperature and time scale. During vitrimer synthesis, the measurement of the temporal increase of ' G and '' G also makes it possible to monitor how the crosslinking reaction progresses and find the gelation point, which occurs approximately when ' '' GG . 13,[40][41] After the gelation point, the crosslinking reaction ends and the storage and loss moduli reach constant values with ' '' GG  . The molten polymer remains then in the "rubbery" state except when destruction of cross-links takes place by thermal degradation. 27 At service temperatures, i.e. in the solid state or below m T , the published results concern mainly the viscoelastic characteristics of vitrimers, or more specifically the creep properties of these materials. Röttger et al. and Caffy et

Microcarriers' shell stability was studied with competitive surfactants or with proteins contained in the MSCs culture medium.