Core-shell polymers from styrene and vinyl acetate for use as wood adhesives.
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Techniques to produce core-shell morphology have been applied to the creation of poly(vinyl acetate) emulsions for use as wood adhesives. These strategies have been used to investigate the molecular origins of some of the shortcomings of poly(vinyl acetate) adhesives, and also to attempt to enhance the properties of these widely used adhesives. A model is presented to predict the incidence of particle formation, which was used to accurately predict that the polymerisation of vinyl acetate in the presence of large polystyrene seed particles would not be possible without the formation of secondary particles. Numerous attempts were made to reduce the incidence of secondary particle formation using the mechanistic basis of the model as a guide, without success. As a result, the inverse route to core-shell morphology was used to create the desired morphology. Microscopic characteristics that favoured the formation of particles containing one centrally located polystyrene core were investigated. Transmission electron microscopy techniques were developed to allow characterisation of the morphology produced in two-stage styrene-vinyl acetate polymerizations Latices having a range of morphologies, including the desired core-shell, were subjected to a range of physical tests to evaluate their performance as wood adhesives. The information gained from this testing was used to correlate performance between tests. The results have also been explained on the basis of microscopic structure.