Agglomeration glass particles

Fig. 7.64 Effect of binder addition rate on the growth of glass particles by agglomeration (Run numbers refer in this and in the following figures to the documentation of data according to Terrazas-Velarde (2010)).

Fig. 7.65 Effect of binder mass fraction in the sprayed droplets (droplet viscosity) on the agglomeration rate of glass particles.

Fig. 7.67 Influence of gas inlet temperature on the agglomeration of glass particles.

PVA Particles. Dispersions were prepared in order to examine stabilization for a core polymer having a glass transition temperature below the dispersion polymerization temperature. PVA particles prepared with a block copolymer having M PS) x 10000 showed a tendency to flocculate at ambient temperature during redispersion cycles to remove excess block copolymer, particularly if the dispersion polymerization had not proceeded to 100 conversion of monomer. It is well documented that on mixing solutions of polystyrene and poly(vinyl acetate) homopolymers phase separation tends to occur (10,11), and solubility studies (12) of PS in n-heptane suggest that PS blocks with Mn(PS) 10000 will be close to dissolution when dispersion polymerizations are performed at 3 +3 K. Consequently, we may postulate that for soft polymer particles the block copolymer is rejected from the particle because of an incompatibility effect and is adsorbed at the particle surface. If the block copolymer desorbs from the particle surface, then particle agglomeration will occur unless rapid adsorption of other copolymer molecules occurs from a reservoir of excess block copolymer. 

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