Masters Theses

Date of Award

12-1999

Degree Type

Thesis

Degree Name

Master of Science

Major

Mechanical Engineering

Major Professor

Mancil W. Milligan

Committee Members

R. Arimilli, M. Parang

Abstract

An extensive experimental investigation was undertaken to study the influence of processing parameters, die configurations and resin type on the production of shot in the melt-blowing process. The addition of nucleating agents toa base resin and the effect these agents have on shot production was also investigated.The processing variables that were investigated included: die air pressure (related to air jet velocity), processing temperature (air and polymer temperature) and polymer mass throughput. The die configuration was varied between a single hole die and a thirty hole die for both conventional and metallocene resins. Data was collected inorder to establish the individual effect of varying a single processing parameter on the production of shot. This data was then used to create an empirical model to predict the amount of shot produced using a single hole die.The thirty hole per inch die produced more shot than the single hole die withall other processing conditions being equal. The metallocene resins also produce more shot than the conventional resins with all other processing conditions being equal. Die air pressure had a strong effect on the shot production; an increase in diy air pressure produced more shot in the web sample. Processing temperature produces a similar trend; an increase in process temperature produced more shot in the web sample. Polymer throughput was different in that an increase in polymer throughput might either increase or decrease the amount of shot in the web sample.IVA couple of empirical models were created using the experimental data collected during this research. These models utilized a dimensionless form of the processing parameters or more traditional fluid mechanics dimensionless variables to predict the amount of shot that would be present in the web sample. The processing parameter model and the traditional variable model both captured the shot production trends of the melt blowing process.Nucleating agents were added to a base resin to increase the base resin crystallization kinetics in an attempt to reduce shot production. The shot productions and the average fiber diameter of the nucleated resins were the same as that of the base resin. Laboratory tests indicated that these additives do provide the accelerated crystallization kinetics in a quiescent environment even though the influence of these additives was not realized in the highly turbulent air jet of the melt-blowing process.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS