**3. Preparation of the copolymers**

The DMAc/LiCl solution is prepared for 1 hour at a temperature of 80° C with mechanical stirring. In a flask equipped with a condenser, we mixed a quantity of the solution of DMAc/LiCl, L-lactide (2, 4 or 8 equiv./ OH) and DMAP catalyst (0.1, 0.5 or 1 equi/OH) then heated it to 80° C with magnetic stirring at different reaction times (8, 16, 24 h). At the end of the reaction, a quantity of ethanol is added in order to precipitate the xylan-g-PLLA. The product obtained is purified with the solvent dimethyl sulfoxide (DMSO) and precipitated in ethanol. The obtained copolymer is dried at room temperature and is characterized by different methods.
