NANOFIBRILLATED CELLULOSE/ACRYLONITRILE BUTADIENE RUBBER COMPOSITES: MORPHOLOGY, MECHANICAL AND DYNAMIC MECHANICAL PROPERTIES

Abstract

Cellulose fibre isolated from agricultural waste material, tapioca stem by physico-chemical method was subjected to a size reduction process to produce nanofibers of average fibre width of 50 nm. This was used to prepare acrylonitrile butadiene rubber (NBR) composite by wet masterbatch technique. Wet masterbatch technique is an eco-friendly process which is more effective compared to the reported dry rubber compounding procedures since colloidal dispersion of polar cellulose fibres are mixed with NBR latex (aqueous dispersion) so as to facilitate the interpenetration of the two polymeric phases without the expense of much energy, assistance of costly equipments or compromising on elastomer strength. Masterbatch maximises the interaction between the nanofiller and the matrix which is reflected in the improved mechanical properties. The effect of nanocellulose concentration on the morphology and mechanical and dynamic mechanical properties of the nanocomposites has been studied. Significant improvement in modulus (60%) and tensile strength (112%) of the composite was observed at an optimum fibre loading of 3 phr. The thermal stability of NBR was improved by 19˚C and the storage modulus was increased by 6 MPa. Scanning electron microscopy revealed that better dispersion of the nanocellulose was possible by masterbatch method.