Effect of the number of polymer arms on the pulping performance of coal water slurry

Abstract

In order to evaluate the effect of polymer arm numbers on the pulping performance (dispersion and stability) of coal water slurry (CWS), this account synthesized four types of homopolymers (two-, three-, six- and eight-arm) by single electron transfer living radical polymerization (SET-LRP). Herein, the polymerization conversion rates and morphology of homopolymers were studied by UV–visible spectroscopy and Scanning electron microscopy. The results showed that the conversion rate of the six-arm homopolymer was the highest, and the polymer arm numbers had a significant effect on its morphology. Subsequently, the effect of the number of polymer arms on the pulping performance was systematically studied. The measurements found when mixed with a six-arm homopolymer, the penetration ratio of Yulin CWS remained at 100 % after 30 days, and the viscosity dropped to 795 mPa·s. Similarly, the penetration ratio of Liuhuanggou CWS also maintained 100 %, and the viscosity dropped to 578 mPa·s. Finally, adsorption experiments and theoretical study revealed an increase in steric hindrance (V_S) would inhibit the approach between particles and disrupt the flocculation state of slurry, thereby effectively enhancing the dispersity and the stability. As a promising dispersant, the six-arm dispersant could be employed in pipeline transportation.