Abstract approved: Title: Computer Modeling of Network Flexibility and Materials with Negative Thermal Expansion

The purpose of this research was to study the flexibility of network structures, and understand how network structures react to changing pressure and temperature. We were especially interested in network structures which show anomalous (very low or negative) thermal expansion behavior. Materials which contract on heating (negative thermal expansion materials) are of great importance since they can be mixed with other materials (normal thermal expansion materials) to make composites which have zero thermal expansion. Materials with zero or low thermal expansion have many applications in thermal shock-resistant materials, electronic devices, space telescope mirrors, stove tops, cook wares and so on. There are two types of low or negative thermal expansion materials. Some anisotropic materials show positive thermal expansion in one or two dimensions which is coupled with negative thermal expansion in the other two or one dimensions. We studied anisotropic thermal expansion behavior of cordierite, p-eucryptite, and NZP (NaZr2P3O12). The problem with anisotropic materials is that microcracking occurs during the heating cycle. Isotropic materials have isotropic thermal expansion which means tha