Process for manufacturing cross-linkable biopolymers

A process for manufacturing a biopolymer chemically modified with a functional group selected from a carbon-carbon double bond, a carbon-carbon triple bond and a nitrogen-nitrogen triple bond, said process comprising the following steps:

• (a) dissolving a biopolymer in an aqueous solution, wherein said biopolymer is selected from a protein, a polysaccharide, a salt thereof, and a mixture thereof;
• (b) reacting the biopolymer with a chemical modifying agent containing a carbon-carbon double bond, a carbon-carbon triple bond, and/or a nitrogen-nitrogen triple bond to obtain a solution containing a biopolymer chemically modified with a functional group selected from a carbon-carbon double bond, a carbon-carbon triple bond and a nitrogen-nitrogen triple bond;
• (c) adding the solution obtained at step (c) to an organic solvent to obtain a suspension containing a precipitate of the biopolymer chemically modified with the functional group selected from a carbon-carbon double bond, a carbon-carbon triple bond and a nitrogen-nitrogen triple bond;
• (d) subjecting the suspension obtained at step (c) to filtration to obtain the precipitate and a filtrate;
• (e) subjecting the filtrate to distillation to recover the organic solvent;
• and
• (f) drying the precipitate to obtain the biopolymer chemically modified with the functional group selected from a carbon-carbon double bond, a carbon-carbon triple bond and a nitrogen-nitrogen triple bond.