Bio-Catalysis for the Functionalization of Cellulose Nanocrystals

In this work, the chemical modification of cellulose nanocrystals (NCs) using an enzyme as a catalyst has been performed by a grafting from reaction, in order to covalently functionalize the external surface of NCs with both poly(L-lactic acid) (PLLA) and poly(epsilon-caprolactone) (PCL) by ring-opening polymerization. Firstly, cellulose nanocrystals were prepared from commercial cellulose microcrystals by acid hydrolysis and then functionalized by using Yarrowia lipolytica lipase immobilized on Lewatit resin as a catalyst. To confirm the success of the grafting reactions, H-1-NMR has been performed as well as FT-IR and Raman spectroscopy. Moreover, thermogravimetric analysis has been used to determine the amount of polymeric chains grafted onto the surface of cellulose nanocrystals. Furthermore, the crystalline nature of the polymeric chains grafted onto the cellulose surface has been studied by DSC, X-ray scattering, as well as SAXS analysis. To our knowledge, it is the first time that a biocatalyst approach has been used to obtain biopolymeric functionalized cellulose nanocrystals.

Automated summary

In this study, the chemical modification of cellulose nanocrystals (NCs) was carried out to covalently functionalize the external surface of NCs with poly(L-lactic acid) (PLLA) and poly(epsilon-caprolactone) (PCL) using an enzyme as a catalyst. Various analytical techniques were used to confirm the success of the grafting reactions and to study the crystalline nature of the functionalized polymeric chains.