Revisiting the surface olefin cross-metathesis of nitrile butadiene rubber on palygorskite nanorods: Product controlling for specific applications

Clays have been widely used for various fields after surface modification. In our previous work, nitrile butadiene rubber (NBR) had been successfully grafted onto palygorskite nanorods (Pal NRs) via the surface olefin cross-metathesis (OCM) reaction and their potential applications were preliminarily explored as nano-reinforcing agent, self-separable adsorbent, or Pickering surfactant. Aimed on a precise manipulation of the products for better performance in such specific applications, the modification of Pal NRs with NBR via OCM was optimized, including different vinyl groups modified on Pal NRs, feeding ratios, solid contents, solvents and reaction times. The reaction time was found as a critical factor for the manufacturing of nitrile butadiene rubber modified palygorskite nanorods (NBR-Pal NRs) as potential nano-reinforcing agent and Pickering surfactant. Overreaction with prolonged reaction time would produce the crosslinked nitrile butadiene rubber-palygorskite nanorods microgels (NBR-Pal MGs) as self-separable adsorbent. Furthermore, the better dispersibility of the Pal NRs and the better dissolubility of NBR could be achieved with the polar solvent, favoring the OCM reaction between the V-Pal NRs and accelerating the formation of the NBR-Pal MGs.