FLOCCULATION OF POLYSTYRENE LATEX WITH MIXTURES OF POLY(P-VINYLPHENOL) AND POLY(ETHYLENE OXIDE)

Poly(13-vinylphenol) (PVPh) was evaluated in conjunction with high mol ecular weight poly(ethylene oxide) (PEG) as a flocculant for monodispe rse surfactant-free polystyrene latex. PVPh was effective with perform ance similar to that of a commercial phenol formaldehyde resin (PFR). Flocculation was not sensitive to PVPh molecular weight in the range 1 500-30 000. PVPh was most effective at intermediate pH values where th e polyphenol was present as dispersed particles in the colloid size ra nge. It is proposed that the flocculation involved hydrogen bond compl exes between the PVPh particles and PEG. Molecular mechanics calculati ons of relative energies of PEO/PVPh complexes with varying hydrogen b onding sequences indicated that hydrogen bonding with adjacent or alte rnating polyether oxygens along the PEO chain was less favorable than that for complexes with bonding of every fourth or fifth oxygen. Polya crylic acid, another polymer capable of hydrogen bonded complexes with PEG, gave no latex flocculation. Kinetic analysis indicated that floc culation was an orthokinetic collision process.