Structural characterization of renewable natural and synthetic polymers for active applications

Worldwide 335 million tons of plastic materials are produced annually and nowadays, a world without synthetic polymers seems unimaginable [1]. But plastics are "almost" forever thus resulting in a negative impact on the environment through water and land pollution. Stringent environmental regulation has led to a growing interest in natural based polymers representing an alternative to the conventional materials. In this context starch deriving from biomass is an excellent candidate for the production of natural based polymers being one of the most abundant biopolymer on earth nevertheless the material suffers of some disadvantages deriving from an excessive rigidity and affinity for water [2]. In this study starch deriving from the pea pods, (Pisum sativum) was used as starting material for the preparation of polysaccharide-based material and, to overcome the above reported limitations, an enzymatic modification with the laccase/TEMPO system was performed [3]. The structure of the modified starch was extensively characterized by means of mono- and two-dimensional NMR spectroscopic experiments. Successively, the modified polysaccharide was lyophilized leading to a compact aerogel characterized by a morphology with irregular pores of dimensions ranging from 200 nm to few microns. The synthesized aerogel was successfully used as carrier of active molecules and the profile of release determined by proton NMR studies.