Technology, critical, importance materials science

MATERIALS SCIENCE IS A CRITICAL TECHNOLOGY for America. In 1987 and again in 1990, the U.S. Department of Commerce included advanced materials such as ceramics, polymers, advanced composites, and superconductors in a short list (1) of very important emerging technologies. The world market based on these advanced materials was estimated conservatively at 600 million by the year 2000. 

RESEARCH UNIVERSITIES ARE IN THE MIDST OF MAJOR CHANGE. Historically, the research universities have been supported by the Government with two theories in mind (1) national security is important, and science and technology are critical to a strong defense and (2) human health is important. The interest in human health persists, an interest in national security persists, but the adversary has given up. The Soviet Union no longer exists. The question now is, What is the rationale for the support of universities—support in the post-Cold War era The Department of Defense, which has nurtured an important set of activities, has a role in electronics and devices, structural materials, and high-performance or advanced-performance materials. 

Polyurethanes (PU) are widely used in a variety of industries (automotive, biomedical, etc.). While the most widespread use of PU in industry is in the form of foams (flexible, rigid, and viscoelastic), an important part is played by PU elastomers [1,2]. The utility of these materials is due to the versatility of their properties, relatively low cost, and well-developed preparation processes such as reaction injection molding (RIM). It is well-established that by varying chemical formulations, one can prepare PU elastomers with Young s modulus ( stif iess ) ranging from soft (-1-2 MPa) to hard (>100 MPa). Understanding the dependence of the properties of PU elastomers on the formulation chemistry is a critical issue in polyurethane science and technology [3-27]. 

Thus, Volume 7 of the series Molecular Sieves - Science and Technology presents descriptions, critical analyses, and illustrative examples of applications of the most important methods for investigations of sorption and sorption kinetics in zeolite systems and related materials. The editors hope that the volume will be helpful for researchers as well as technologists who are confronted with the important phenomena of adsorption and diffusion in microporous materials as they occur, for instance, in separation processes and catalysis. 

This review is focused on the science and technology of framework metal-containing zeotype materials, a critical and increasingly important class of catalyst. In the following paragraphs, first the structural characteristics of zeo-Htes, which are close and well investigated relatives of zeotype materials, will be briefly summarized. Then the role of the framework metal for the structural and surface chemistry of zeolite and zeotype materials will be introduced. 

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