Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Pittman Jr., Charles U.

Committee Member

Toghiani, Hossein

Committee Member

Zhang, Jilei

Committee Member

Mead, Keith T.

Committee Member

Henry, William P.

Date of Degree

12-13-2008

Original embargo terms

MSU Only Indefinitely

Document Type

Dissertation - Campus Access Only

Major

Organic Chemistry

Degree Name

Doctor of Philosophy

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

This dissertation includes two parts: Part I “natural fiber/thermoplastic composites” and Part II “studies of organo-clay synthesis and clay intercalation by epoxy resins”. The use of light weight renewable natural materials instead of heavy mineral-based materials is important to generate lighter materials for sustainable human development. Renewable natural fibers have already been used to reinforce thermosetting and thermoplastic polymer composites. The abundance of hydroxyl groups in natural fibers causes two problems: (1) high water moisture uptake and (2) incompatibility with hydrophobic polymer matrices. Surface modifications have been used to solve these problems. In part I of this dissertation, the modifications of wood fiber/flour by acid chlorides and maleated polypropylene were studied. High density polyethylene (HDPE)/wood flour (WF) composites were investigated in Chapter 1 of Part I. Polypropylene (PP)/WF composites were studied in Chapter 2 of Part I. In Chapter 3 of Part I, kenaf/PP composites were explored. Finally, the effect of carbon nanofibers (CNF) and composite blending processes were studied in Chapter 4 of Part I. Composite flexural properties and water absorption properties were evaluated. Flexural strengths and flexural moduli were obtained by four-point bending tests. Micromorphologies were investigated by scanning electron microscope (SEM). Part II presents studies of organo-clay syntheses and the mechanism of clay intercalation by epoxy resins. Ammonium and imidazolium pillaring agents were synthesized and then used to modify clay. A pillaring agent with epoxy functional groups was also synthesized. Clay intercalation by epoxy resins was affected by the epoxy resin polymerization rate, viscosity and temperature. The diffusion rate of monomers and polymers into and out of clay galleries is a function of temperature and a major factor in intercalation. The clay’s degree of nano dispersion in epoxy composites were investigated by TEM. The clay thermostabilites were studied by TGA.

URI

https://hdl.handle.net/11668/17455

Comments

wood||clay||composite

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