The use of polyelectrolyte stabilisers for suspension polymerisation: the effect of pH on particle size distribution

Abstract

Ammonium polymethacrylate (APMA) and sodium polymethacrylate (PMA‐Na) were used as suspending agents for the suspension polymerisation of methyl methacrylate (MMA). The effect of pH on particle sizes and the stabilisation mechanism were examined. Increasing the pH caused a decrease in the particle sizes, and the formation of fine particles with diameters smaller than 10 µm. The amount of suspending agent required to stabilise a monomer dispersion and to prevent coalescence during suspension polymerisation decreases with increasing pH. The prevailing stabilisation mechanism that governs the dispersion stability is probably the electrosteric mechanism. Copyright © 2006 Society of Chemical Industry

Suspension Polymerization Processes

“…In that case, the interfacial tension was almost independent of the suspending agent concentration and the continuous phase was non-Newtonian (viscosity decreased with increasing agitation rate). Similar results were obtained when ammonium polymethacrylate was used as a suspending agent [53], [54]. The viscosity of the continuous phase also depended on the pH.…”

“…The initial value of the pH exerted a significant influence on the drop sizes and particle sizes, without affecting the interfacial tension. With both stabilisers, monomer hydrolysis led to diminution of pH during the polymerization; but the continuous phase remained alkali [54]. When sodium polymethacrylate was used, increases in the volume fraction of monomer decreased the Sauter mean drop diameter but, when a minimum value was reached, subsequent increases in the monomer fraction led to increases in drop diameter [52].…”

Suspension polymerisation of methyl methacrylate using ammonium polymethacrylate as a suspending agent

“…It has been shown that increasing the pH of the continuous phase triggers an electrosteric stabilisation mechanism that enhances the stability of the drops and causes the decrease of the particle sizes (Georgiadou and Brooks, 2006). Now, we have shown that increasing the pH of the continuous phase causes the viscosity of the continuous phase to decrease (see Fig.…”

Nonaqueous polymerization of vinyl chloride: An environmentally friendly process

“…The type of suspending agent was found to exert a strong influence on the shape and morphology of the polymer particles, as it also does in typical suspension polymerization processes. [11][12][13][14][15][16] The shape of the particles varied from regular to irregular and the surface varied from even and smooth to rough and uneven, depending on the type and HLB value of the suspending agent, as shown in Table I.…”