A new route to polymeric materials derived from chitosan and natural rubber

In this work, the synthesis and characterization of a new polymer, natural rubber-g-chitosan, from biopolymers available in nature is reported. In this process, soft and amorphous natural rubber (NR) is converted into a relatively more dimensionally stable new polymer (glass transition temperature changes from −68 to +94.5 °C), with versatile solubility in a variety of common organic solvents. For this purpose, mild epoxidation of NR is carried out to provide a reactive handle for the grafting of chitosan. Thus, chitosan-grafted natural rubber with different chitosan loading have been synthesized and characterized. The characterization of the new polymers revealed that the grafting process resulted in enhanced glass transition temperature in comparison to NR, remarkable improvement in thermal stability in comparison to NR and chitosan and the much needed solubility for the chitosan component, which is otherwise insoluble in common organic solvents. The NR-g-chitosan is fully amorphous in the solid state, similar to NR. These value-added characteristics promise the utility and processability of the newly synthesized materials in adhesives, packaging industries and in many other areas where natural rubber and chitosan are vitally employed.