CIMTEC '98

 

Florence, Italy 14th-19th June 1998

INORGANIC-ORGANIC HYBRID MATERIALS USING CARBOYLATE-ALUMOXANE. Andrew R. Barron,* Department of Chemistry and Department of Mechanical Engineering, Rice University, Houston, Texas 77005

Ceramics have excellent mechanical properties such as heat-resistance,

wear-resistance, and strength, however, they are typically brittle and

difficult to form into complex shapes. In contrast, organic polymers and

resins are readily processed but show poorer physical properties. It has

long been a goal of materials synthesis to prepare inorganic -organic hybrid

composite materials that combine properties of an organic polymer with that

of a ceramic. We report that p-hydroxybenzoate or lysine substituted

alumoxanes are readily prepared from boehmite, [AlO(OH)]n, with the parent

acid. The surface hydroxides and amines of these alumoxanes reacts with

expoxides such as diglycidylether bisphenol-A (DGEBPA) to give a new class

of inorganic-organic hybrid material. Details of the process will be

reported as well as the results of product analysis. Applications in coating

and corrosion resistant interlayers will be presented.

CARBOXYLATE ALUMOXANES: ENVIRONMENTALLY BENIGN PRECURSORS FOR DEVELOPING ALUMINUM BASED CERAMIC MEMBRANES AND FILTERS. Christopher D. Jones, Andrew R. Barron,* Department of Chemistry, Rice University, Houston, Texas 77005; Mark R. Wiesner, Department of Environmental Science and Engineering, Rice University, Houston, TX 77005.

The objective of our research is the development of nano, meso, and macro

scale aluminum based ceramic membranes and filters from carboxylate

alumoxanes. Carboxylate alumoxanes are organic substituted alumina

nano-particles synthesized from boehmite in aqueous solution which are an

inexpensive and environmentally-benign precursor for the design and

fabrication of these membranes. The size of the carboxylate ligand on the

alumoxane controls the porosity during sintering to alumina. By varying the

size of the ligand, membranes of different porosity can then be fabricated.

The membranes will be characterized by atomic force, scanning electron, and

transmission electron microscopy, X-ray diffraction, and flow measurements.

AQUEOUS SYNTHESIS OF WATER SOLUBLE ALUMOXANES: ENVIRONMENTALLY BENIGN PRECURSORS TO ALUMINA AND ALUMINUM BASED CERAMIC MATERIALS, Rhonda L. Callender, Department of Chemistry, Rice University, Houston, TX 77005; Andrew R. Barron*, Department of Chemistry and Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005; Mark R. Wiesner, Department of Environmental Science and Engineering, Rice University, Houston, TX 77005.

The objective of our research is the development of an environmentally

benign process for the fabrication of alumina-based ceramic materials. We

have designed an alternative synthetic pathway to alumina ceramics which

does not utilize toxic reagents or organic solvents; the aqueous synthesis

of water soluble carboxylato-alumoxane precursors from inexpensive boehmite

feedstock. The synthesis and characterization of these new alumoxanes will

be presented along with their conversion to a- and g-alumina, as well as

metal doped and ternary aluminas. SEM, TEM, XRD, surface area and

spectroscopic measurements of the alumoxane and the resulting aluminas will

be discussed. The potential environmental impact of the new alumoxane

methodology as compared to traditional approaches will be presented.

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