Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Engineering Science

Major Professor

James L. White

Committee Members

Donald Bogue, John F. Fellers, J. E. Spruiell, L. C. Wadsworth


It is the purpose of the present research to characterize the particulate structure in the compounds for a range of small solid particulates. These include a wide range of calcium carbonates both in uncoated and coated modes, carbon blacks, uncoated and coated talc, mica, etc. The matrix polymers used are polystyrene and polypropylene.

The present research involves (i) development of methods and the interpretation of them to characterize the state of particles and their structure in plastics, (ii) to determine how these particulate structures are developed in the mixing process.

The primary particulate structure of concern is the state of dispersion. The methods of characterizing the particulates and the state of dispersion used in the present research include (i) sedimentation volume experiments, (ii) optical microscopy, (iii) scanning electron microscopy, (iv) small angel light scattering, and (v) electrical conductivity measurements.

The particulate structure in plastics covers a wide range in size and in quantity. Optical and scanning electron microscopy gives us direct information on particulate structures. The small angle light scattering technique is a new method of charactering the dispersion of small particulates. The primary structure of particulates characterized by these methods is the agglomerate.

Electrical conductivity measurements were used to determine the levels of dispersion for compounds of carbon black. The concept of three-dimensional network structures of particulates was developed associated with this experiment.

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