**5. Conclusion**

The modification of xylan by grafting the PLLA on the xylan extracted from the sawdust of chestnut was carried out in this work. The synthesis of branched xylang-PLA co-polymers is carried out from L-lactide and xylan using DMA as solvent for the xylan and 4-dimethylaminopyridine (DMAP) as catalyst at a temperature of 80° C. These copolymers are characterized and infrared analysis has shown the appearance of the characteristic band of the esters at 1784 cm−1 and of other bands of the group CH3 on the xylan-g-PLLA spectrum. Following the <sup>1</sup> H NMR analysis, the appearance of the PLLA aliphatic protons was observed on the spectrum of the grafted xylan. The xylan copolymers are insoluble in water. The higher the DS, the more difficult the solubility is in water. Dynamic mechanical analysis has shown that Tg of the xylan-g-PLLA film is 147°C.
