The anatase → rutile transformation reaction of TiO2 prepared in contact with amorphous aluminum phosphate and with fume silica has been investigated as a function of temperature by x-ray diffraction methods. It is observed that the anatase → rutile transformation in such systems becomes greatly inhibited and the Raman spectra of titania on such surfaces exhibit features that indicate substrate-TiO2 interfacial reactions.

Measurements of the engineering constants E, G, and v are routinely made for polymeric materials. If these materials are isotropic, these measurements should satisfy the relationship G = E/2(1 + v). However, many past measurements have indicated that this relationship is not satisfied. This raises questions about the assumptions of material isotropy and the applicability of Hooke's law. The methods used to measure these engineering constants for a number of different polymers are first described. Then, new results obtained in the current investigation are presented, indicating that the elastic constants do in fact satisfy the isotropic relationship for strains up to 0.5%. However, it is shown that at strain levels above this level, the relationship between stress and strain is nonlinear.