Influence of Crosslinking Density on Antioxidant Nanocellulose in Bio-degradation and Mechanical Properties of Nitrile Rubber Composites

Abstract

Nanocellulose antioxidant (Aox-NCC) was used as reinforcement and crosslinking agent in nitrile butadiene rubber (NBR) composites. The crosslinking density and volume of rubber bonded in the matrix were increased up to 3 phr and no significant improvement between 4 phr and 5 phr was recorded. The interactions of gallic acid and NCC was found to occur between the -OH and -COOH groups, as revealed by Fourier Transform Infra-Red (FTIR) and Nuclear Magnetic Resonance (NMR) analysis. Crystallinity index of Aox-NCC was increased more than 11 %, recorded by X-ray diffraction (XRD) analysis. Meanwhile, the thermal stability of Aox-NCC was increased 30°C, analyzed by thermogravimetry (TG). With the addition of 3 phr Aox-NCC, tensile strength and modulus at 500 % for NBR composites were increased significantly up to 20 %. There was no significant improvement on modulus at 100 %, modulus at 300 %, elongation at break and tear strength. The degradability of NBR composites within 6 months period was improved significantly at 5 phr of Aox- NCC. Increase in carbonyl group after soil burial test with the existence of cracks, voids and degradable parts of NBR composites were revealed. This demonstrated that, Aox-NCC plays a secure function to reinforce NBR composites.