There is a considerable range of materials that fall within the interest of the Time Dependent Materials Division. With respect to ceramics at high temperatures a major point of inquiry is the micro-structural source of time dependence, e.g., whether the latter derives from an amorphous intergranular boundary layer of fixed dimensions, or whether that grain boundary widens under stress and high temperature. The range of problems in polymers is larger inasmuch as we deal here with of materials that can be grouped into several classes. T g designates the glass transition temperature. Multiphase polymers contain physically distinct phases.
Blends consist of 'mixtures' of different chains forming separate phases.
Their phases are much larger and much less uniform in size than those formed by block and graft copolymers or simpolymers. Multiphase polymers possess characteristics like those of particulate composites. While it is difficult to make sweeping generalizations about these classes of polymers and their response to load or deformation, some observations are possible. The MFT-equation does this for temperature and pressure. It contains the WLF-equation as a special case.