Production of polystyrene particles via aerosolization

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references.Issued also on microfiche from Lange Micrographics.The objectives of this research were to identify any conditions that would be appropriate for producing hollow polystyrene particles using aerosolization and to study the effect of various experimental conditions upon particle characteristics. We found that particles were pure, amorphous, and not hollow. Average size decreased with increasing furnace temperature, but it increased with polymer concentration and solution viscosity. Carrier gas flow rate did not influence particle size. Unlike solvent type, concentration, and carrier gas flow rate, furnace temperature was important to particle morphologies. Particle surface area decreased with increasing furnace temperature and solution concentration. In contrast, surface area increased with carrier gas flow rate and solution viscosity. The formation of solid PS particles was a consequence of solvent evaporation without phase separation, resulting in a continuous PS concentration profile inside the droplet. Like the formation of PS particles at high temperature studied by Chiang and Prud'homme, a uniform PS concentration within droplets was likely in our case. As solvent evaporates, van der Waals forces and subsequent entanglement of polymer chains causes solidification. The PS-benzene phase diagram suggests that precipitation does not occur. In order to obtain hollow particles, a solvent that will allow PS to phase separate in the range of operation temperature should be used. Alternatively, a change in operation temperature to a temperature that is in the region of PS phase separation is suggested. However, it is impractical to change the furnace temperature in the present system (PS in benzene) because the lower critical solution temperature of the system is too high. Use of such a high temperature would lead to melted, non-spherical PS particles