Date of Award

Fall 1997

Document Type

Thesis

Degree Name

Master of Science in Materials Science and Engineering - (M.S.)

Department

Committee for the Interdisciplinary Program in Materials Science and Engineering

First Advisor

Marino Xanthos

Second Advisor

Ken K. Chin

Third Advisor

Henry Shaw

Abstract

The primary objective of this study is to introduce tertiary hydroperoxide functional groups into polypropylene (PP) melt by injecting air. This was done first by mixing additive free polypropylene powder with air in a batch mixer. The influence of air flow rate, temperature, mixing time and rotor RPM on the concentration of hydroperoxide groups were studied. Iodometric analysis and fourier transform infrared spectroscopic analysis were the techniques used to detect and quantify the concentration of hydroperoxide groups. In the second phase of the study, hydroperoxide groups were introduced in polypropylene through reactive processing in a single screw extruder. It was possible to incorporate hydroperoxide groups at concentration as high as 0.089 mole/kg of PP. The viscosity changes of the modified polypropylene corresponding to molecular weight reduction were studied using a capillary rheometer.

Preliminary scrubbing experiments were carried out to study the reactivity of one hydroperoxidized polypropylene sample towards NO and further experiments are recommended to establish suitable testing protocol. It has been shown in the past that organic hydroperoxides react with NO to form nitrites and nitrates. It was also demonstrated that γ-ray irradiated PP in moist air produced hydroperoxides that could be made to react with NO. The ultimate objective of this research is to use hydroperoxidized polypropylene for selective NO removal for pollution control.

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