Changes in the rheometric,morphological and mechanical properties of nitrile rubber composites by the use of different concentrations of cellulose nanofibers

Abstract

Cellulose nanofibers were produced with waste from the paper industry, in a stone grinder and were used as filler in elastomeric composites in the acrylonitrile-butadiene copolymer (NBR). Two different cellulose mass concentrations (0.5 and 2.0 wt%) were ground in water and incorporated in concentrations of 0, 10 and 20 phr by the coagulation of the NBR, followed by drying. The other components of the formulation were incorporated and vulcanized in an open mixer and molded by compression. Due to the proposed grinding it was possible to obtain nanocellulose, in the range of 20.5 nm to 83.6 nm at an average diameter of 42.8 nm for the solution produced with 2.0 wt% and 18.3 nm at 90.5 nm at an average diameter of 44.3 for the solution with 0.5 wt%. The composites with a 20 phr of nanofiber presented lower vulcanization times and better mechanical properties before and after accelerated aging for 7 days, as well as a superior resistance to gasoline and diesel than the NBR and the samples with 10 phr. A tear strength of 61 N.mm⁻² was obtained at the concentration of 20 phr and 0.5 wt% of incorporated nanofibers in line with a shorter vulcanization time.