Polythermal Nucleation Kinetics of NaHCO3-Na2CO3-H2O in the Presence of Polyectrolyte Additives

Abstract

The particle size distribution (PSD) of substances is important to their transportation and packaging. The crystal nucleation kinetics measured from the metastable zone width (MSZW) and/or the induction time are vital to the control of the PSD. In this work, the existence of three polyelectrolyte additives (sodium polystyrene sulfonate (SPS), Polyacetic acid (PAA) and sodium carboxymethylcellulose (CMC)) showed varying effects on the MSZW and induction times of NaHCO₃-Na₂CO₃-H₂O system. SPS lowers the MSZW and induction time while both parameters were increased in the presence of CMC and PAA. The nucleation inhibition effects were observed to be prominent for both PAA and CMC resulting in observed finer PSDs as cooling rate, b increases from 0.5 K/min to 2.65 K/min. The PSD increases with b for both pure and SPS additive, whereas they decrease for both PAA and CMC.