Cellulosic bionanocomposites based on acrylonitrile butadiene rubber and Cuscuta reflexa: adjusting structure-properties balance for higher performance

Design and manufacture of cellulosic nanocomposites with acceptable performance is in the period of a transition from fantasy to reality. Typically, cellulosic nanofillers reveal poor compatibility with polymer matrices. Thus, adjusting the balance between structure and properties of cellulosic bionanocomposites by careful selection of parent ingredients is the first priority. Herein, we incorporated Cuscuta reflexa derived cellulose nanofibers (CNFs) into acrylonitrile-butadiene rubber (NBR) for high-performance elastomeric applications. Tensile and tear strength of NBR improved by ~ 125 and ~ 105 %, respectively at a very low loading of 4 phr CNFs, as a result of interfacial bonding, as evidenced by fractographic analysis. In parallel, the temperature at which maximum degradation occurs (Tmax) of NBR rose by 14 °C. The swelling index and molar uptake of toluene were also lowered. The Wolff-activity coefficient, hardness, abrasion resistance, and cross-link density were all improved correspondingly. The positive shift in glass transition temperature and the fall in the loss tangent peak height for bionanocomposites proved the effective immobilization of NBR chains by well-dispersed CNFs. The hydrogen bonding interaction between –OH groups of CNFs and –CN groups of NBR might be responsible for the superior performance of NBR/CNF composites, which is confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD).