Polymer compositions comprising cross-linked polymers comprising boronic ester functions enabling exchange reactions, process for preparing them and their use

A composition comprising (a) cross-linked polymers containing exchangeable pending links and exchangeable cross links, by boronic ester metathesis reactions;

• and (b) free monofunctional boronic esters, said boronic esters being chosen from among the following dioxaborolane and dioxaborinane rings of formulas (EB1) and (EB2) below:
• in which
• Rx, Rw and Rv are identical or different and each represents a hydrogen atom or a hydrocarbon radical or form together, as a pair, an aliphatic or aromatic ring,
• Ry is a hydrocarbon radical linked to the boron atom of the dioxaborolane or dioxaborinane ring by a covalent bond through a carbon atom,
• wherein the composition (a) of cross-linked polymers is prepared by copolymerisation of the following compounds:
• (a′) precursor monomers to then ioplastic polymers comprising at least one pending boronic ester group, said pending boronic ester group not containing any polymerisable group;
• (b′) cross-linking agent comprising at least one boronic ester group enabling the formation of a network of cross-linked polymer containing pending functions and cross-links that are exchangeable by boronic ester metathesis reactions;
• said boronic esters being chosen from among the dioxaborolane and dioxaborinane rings of formulas (EB1) and (EB2).