Bionacomposites based on nanocellulose and natural rubber

Abstract

Natural rubber (NR) is a material with remarkable properties and applications in a wide range of materials. However, its properties can be modified and tailored for the development of new functional polymers with specific properties, in order to contribute to the growing trend in renewable materials for the substitution of fossil-derived counterparts. The nanocomposites are interesting materials, which presents high improvements in thermomechanical performance with the addition of low amounts (3 a 5%) of a nano-reinforcing agent. The use of nanocelluloses for this purpose can lead to novel natural rubber films or membranes, without changing the intrinsic properties of the matrix. In this context, Bacterial Cellulose (BC), a special kind of nanocellulose produced by microorganisms, represents a very promising filler for NR, based on its unique structure and properties. Natural fibers, mostly as different forms of cellulose fibers, have been tested as fillers for NR, but their poor compatibility with the matrix, arising from their polar character contrasting with the non-polar structure of NR, tends to give rise to composites with a modest improvement in mechanical properties. The purpose of this project is to increase the compatibility between the two components, based on the polymerization of a thin layer of polymer, such as polystyrene or an acrylic polymer, around the nanocellulose fibers. The polymerization process will be carried out in an aqueous suspension of cellulose fibers, without organic solvents. It should be highlighted that the modification of BC by appending non-polar polymers to it in an aqueous environment, i.e. a green chemistry approach, associated with the use of renewable resources, is innovative, has high scientific and technologic potential and was never reported previously, all facts that give support to the development of the project. In short, the aim of this project is the study of the admicellar polymerization of vinyl monomers around the BC fibers and their use in nanocomposite materials based on a natural rubber matrix. (AU)