Particles containing reversible covalent bonds which may be sequentially formed and broken multiple times

A method for sequentially forming and breaking a reversible covalent bond -A---B- in a particle-containing entity P-(A---B-M)x wherein P is a solid particle attached to at least one polymer M through one or several reversible covalent bonds -A---B-,

• A and B are functional groups respectively grafted to P and M thus forming the P-(A---B-M)x particle-containing entity with x being greater than or equal to 1,
• M is a linear, branched, hyperbranched, grafted, comb-like, star-like, cyclic, a homopolymer, a block copolymer, a random copolymer, a gradient copolymer, an alternating copolymer or a multiblock copolymer and has a degree of polymerization comprised between 5 and 1000 and
• wherein the reversible covalent bond -A---B- is selected from the group consisting of an imine, a disulfide, a boronic ester or an acetal and wherein one of functional groups A and B comprises an amine function, a hydroxylamine function or an imine function, and the other comprises an aldehyde function, a ketone function or an imine function so that the resulting -A---B- reversible covalent bond is an imine, said method comprising the following steps:
• attaching the functional group A to the surface of the solid particle P, thereby forming A-functionalized particles P or providing said A-functionalized particles P;
• attaching the functional group B to a polymer M, thereby forming B-functionalized polymers M or providing said B-functionalized polymers M, and wherein the functional group B is able to form a reversible covalent bond with the functional group A;
• reacting the A-functionalized particles P with at least one B-functionalized polymer M to form a reversible covalent bond between the functional groups A and B, thereby forming the P-(A---B-M)x;
• breaking the covalent bonds -A---B- that link the A-functionalized particles and the B-functionalized particles;
• and
• recovering the A-functionalized particles P after the breaking of the covalent bond(s) -A---B- by physical separation.

A method, for sequentially forming and breaking a reversible covalent bond -A---B- in a particle-containing entity P-(A---B-M)x wherein P is a solid particle attached to at least one polymer M through one or several reversible covalent bonds -A---B-,

• A and B are functional groups respectively grafted to P and M thus forming the P-(A---B-M)x particle-containing entity with x being greater than or equal to 1,
• M has a degree of polymerization comprised between 5 and 1000 and
• wherein the reversible covalent bond -A---B- is selected from the group consisting of an imine, a disulfide, a boronic ester or an acetal wherein the polymer M is a stabilizing agent capable of dispersing the particle P in a medium and the particles P are pigments selected from the group consisting of TiO2, Cr2O3, Fe2O3,Fe3O4 anthraquinones, phthalocyanines, perylene, quinacridone or indigoid, said method comprising the following steps:
• attaching the functional group A to the surface of the solid particle P, thereby forming A-functionalized particles P or providing said A-functionalized particles P;
• attaching the functional group B to a polymer M, thereby forming B-functionalized polymers M or providing said B-functionalized polymers M, and wherein the functional group B is able to form a reversible covalent bond with the functional group A;
• reacting the A-functionalized particles P with at least one B-functionalized polymer M to form a reversible covalent bond between the functional groups A and B, thereby forming the P-(A---B-M)x;
• and,
• breaking the covalent bonds -A---B- that link the A-functionalized particles and the B-functionalized particles.