Lipase catalyzed synthesis of biopolyester and related clay-based nanohybrids
Résumé
Biosynthetic pathway, like enzymatic ring opening polymerization (ROP) of lactones, attracts attention as a new trend of biodegradable polymer synthesis due to its non-toxicity, mild reaction requirement and recyclability of immobilized enzyme. Besides the enzyme-catalyzed synthesis of biopolyesters, key researches are conducted nowadays on the elaboration of biocomposites in combination with inorganic (nano)particles. The goal is to improve some of these polyesters properties for specific biomedical applications. In parallel, the use of clays as inorganic porous supports to immobilize enzymes has also been described. This chapter aims at presenting the use and development of original catalytic systems based on lipases which are efficient for polyester synthesis and allowing the preparation of hybrid materials based on clay nanoparticles grafted with such polyesters. For this, ε-caprolactone (ε-CL) polymerization catalyzed by Candida antarctica lipase B (CALB) was carried out in the presence of montmorillonite and sepiolite clays to obtain organic/inorganic nanohybrids through polymer chains grafting and growth from the hydroxyl groups of the clay. Both the free form and immobilized form of CALB have been tested as catalytic systems and their efficiency has been compared. The polymerization kinetics and resulting products were fully characterized with NMR, SEC, DSC and TGA analyses. © 2011 Nova Science Publishers, Inc.