Kanwen Yang

Abstract

To improve the materials' resistance to atomic oxygen, the aromatic polyamic acid based on 4,4'-oxydiphthalic anhydride (ODPA), 3,4'-oxydianiline (ODA) and mellitic dianhydride (MADA) was synthesized and allowed to react with the complex (4- amino-N,N ' -disalicylidene- 1 ,2-phenylenediaminato)(N,N ' -disalicylidene- 1 phenylenediaminato)zirconium (IV), Zr (adsp)(dsp), in the presence of dicyclohexylcarbodiimide (DCC). The resulting Zr pendent polyamide acid was cast onto glass substrates, and thermally imidized. The synthesized polyamic acids and polyimides were characterized by Thin Layer Chromatography (TLC), Fourier Transform Infrared (FTIR), Proton Nuclear Magnetic Resonance ('H NMR) and Gel Permeation Chromatography (GPC), along with Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) for investigating their thermal properties. Spectroscopic results of Zr(adsp)(dsp), polyamic acids and polyimides were consistent with their proposed structures. GPC results indicate that a moderate degree of polymerization occurred. Decomposition temperatures of Zr pendent polymers, in air, are above 400 C, which are similar to previously made Zr pendent polymers. Two layer 10% mol Zr pendent polyimide films were also made. All the imidized films passed a solvent resistance test which involved immersion in acetone, toluene, 1- methyl-pyrrolidinone (NMP), chloroform and dimethysulfoxide (DMSO) for 30 minutes followed by fingernail crease. Their atomic oxygen resistance were studied by Scanning Electronic Microscopy (SEM) before and after atomic oxygen erosion in a plasma asher. Erosion of the Zr pendent polyimide film left a white surface residue, which was due primarily to zirconium oxide formation. The generation of a uniform zirconium oxide layer protects a preponderance of the original material. It is noticed from the SEM results that an improvement of atomic oxygen resistance was achieved from Zr pendent polyimide compared to its parent polymer. In comparison to LARC-IA, the Zr pendent polyimide has similar thermal stability, but with lower Tg and melting point, 171.8 and 236.5 C.

Library of Congress Subject Headings

Polymers; Aromaticity (Chemistry); Zirconium oxide

Publication Date

5-1-1999

Document Type

Thesis

Department, Program, or Center

School of Chemistry and Materials Science (COS)

Advisor

Illingsworth, Marvin

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: QD381 .Y364 1999

Campus

RIT – Main Campus

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