Flocculation of Polystyrene Latex with Mixtures of Poly(p-vinylphenol) and Poly(ethylene oxide)

Poly(p-vinylphenol) (PVPh) was evaluated in conjunction with high molecular weight poly(ethylene oxide) (PEO) as a flocculant for monodisperse surfactant-free polystyrene latex. PVPh was effective with performance similar to that of a commercial phenol formaldehyde resin (PFR). Flocculation was not sensitive to PVPh molecular weight in the range 1500−30 000. PVPh was most effective at intermediate pH values where the polyphenol was present as dispersed particles in the colloid size range. It is proposed that the flocculation involved hydrogen bond complexes between the PVPh particles and PEO. Molecular mechanics calculations of relative energies of PEO/PVPh complexes with varying hydrogen bonding sequences indicated that hydrogen bonding with adjacent or alternating polyether oxygens along the PEO chain was less favorable than that for complexes with bonding of every fourth or fifth oxygen. Polyacrylic acid, another polymer capable of hydrogen-bonded complexes with PEO, gave no latex flocculation. Kinetic analysis indicated that flocculation was an orthokinetic collision process.