Resource utilization of polystyrene waste by preparation of high performance dispersant for coal-water slurry

In present paper, structures and properties of degradation products of polystyrene (PS) waste were characterized by gel permeation chromatography (GPC), thermogravimetric (TG) analysis, Fourier transform infrared (FT-IR) spectroscopy, gas chromatography-mass spectrometry (GC-MS), and thus the degradation conditions including temperature, time, and assistant type and dosage were investigated and optimized. It is suitable to use 1.0 wt% K2S2O8 as an assistant to degrade PS waste at 300 & DEG;C for 24 h. Subsequently by sulfonation and neutralization reactions, the degraded PS was prepared into sodium polystyrene sulfonate (PSS), a common dispersant for coal-water slurry (CWS). The performance of PSS with different molecular weights and sulfonation degrees was studied. Experimental results showed that the PSS with the sulfonation degree of more than 75%, prepared from the degraded PS having number average molecular weight (M-n) of about 9000, was appropriate for dispersion and stabilization of CWS suspensions. Additionally, compared with commercial dispersant NSF, the obtained PSS had a better performance for CWS. CWSs prepared with dispersant PSS exhibited pseudo-plastic or shear-thinning rheological behaviors. Combined with coal-water slurry technology, a new approach is provided for resource utilization of PS waste.

Automated summary

In this study, the structures and properties of degradation products of polystyrene (PS) waste were characterized, and the optimal degradation conditions were investigated using various analytical techniques. It was found that using 1.0 wt% K2S2O8 as an assistant at 300°C for 24 hours was suitable for degrading PS waste. The degraded PS was then prepared into sodium polystyrene sulfonate (PSS), which showed excellent performance as a dispersant for coal-water slurry (CWS) when it had a sulfonation degree of more than 75% and a number average molecular weight (Mn) of about 9000.