The surface characterisation of polymer latices prepared with specific surface groups

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Goodall, A.R., 1976. The surface characterisation of polymer latices prepared with specific surface groups. PhD, Nottingham Trent University.

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Abstract

Several detailed aspects of the preparation and characterization of polystyrene lattices produced in the absence of added soap have been studied.

Kinetic experiments have been carried out at varying temperatures. These studies showed that the rate of polymerisation per particle was directly proportional to the particle was directly proportional to the particle radius and that growth did not appear to occur solely within the particles, nuclei being continuously formed in the aqueous phase which undergo heterocoagulation with the primary particles.

The presence of 'anomalous particles' has been confirmed and investigated. Their formation is due to the removal of monomer from the particles prior to electron microscopy. The monomer concentration within the particles is heterogenous, this heterogeneity is probably due to the presence within the particles of a region of low molecular weight (~1000) material which arises during particle nucleation.

Particle nucleation is thought to occur via either a precipitation or micellisation process involving free radical oligomers of ~500 molecular weight. It is demonstrated that if this is the case and these nuclei are stable, they can become unstable on further growth. Coagulation then occurs until stability is regained. An initial decrease in number of particles ml-1 has been observed in all reactions studied using electron microscopy. A similar decrease has also been observed in reactions followed using lase light scattering.

It was found that steam stripping was an efficient technique for removing monomer and benzaldehyde from latres these moieties being present even after prolonged discuis. Benzaldehyde was found to be capable of initiating styrene polymerization in the presence of light to produce a latex, and also the presence of benzaldehyde within a latex could result in the incorporation onto the particle surfaces of weak acid groupings.

The use of potassium peroxydiphosphate as an initiator for emulsion polymerisation has been studied. It was found incapable of initiation when used alone. In the presence of heavy metal ions latices were produced stabilized by phosphate groups.

Item Type:

Thesis

Creators:

Goodall, A.R.

Date:

1976

ISBN:

9781369324877

Identifiers: