Lignosulfonate as dispersant for layered double hydroxide in nitrile–butadiene rubber composites

• SLS–LDH complex has been successfully prepared by in-situ method.
• The presence of SLS improved the dispersion of LDH in NBR matrix.
• The mechanical properties of NBR can be significantly enhanced by SLS-LDH.

Nitrile–butadiene rubber (NBR) based layered double hydroxide (LDHs) composites have been prepared through melt-compounding method using sodium lignosulfonate modified LDH (SLS–LDH) as a filler obtained by in-situ synthesis method. The composites were characterized in terms of LDH particles dispersion, mechanical properties and thermal properties. Both X-ray diffraction and scanning electron microscopy analysis data of the composites showed that layered SLS–LDH particles were obtained and SLS improved the dispersion of LDH particles in the NBR matrix. Experimental results indicated that both pristine LDH and SLS–LDH improved the mechanical properties of NBR composites while SLS–LDH showed a more obvious reinforcing ability compared with pristine LDH. The thermal stability of composites containing SLS–LDH was remarkably improved when 50% weight loss was selected as a point of comparison in thermogravimetric analysis. Differential scanning calorimetry analysis data showed that the glass transition temperature of the SLS–LDH/NBR composites increased when compared with LDH/NBR composites indicating the enhancement of interactions between NBR chains and LDH particles in the presence of SLS.