Properties history

Material properties Histories include incidents involving hydrogen (a highly reactive gas), propylene, dimethyl ether, propane, cyclohexane (possibly partly... 

Richards AB, Krakowka S, Dexter LB, et al. Trehalose a review of properties, history of use and human tolerance, and results of multiple safety studies. Food Chem Tox 2002 40 871. 

To gain an understanding of the composition of the reservoir rock, inter-reservoir seals and the reservoir pore system it is desirable to obtain an undisturbed and continuous reservoir core sample. Cores are also used to establish physical rock properties by direct measurements in a laboratory. They allow description of the depositional environment, sedimentary features and the diagenetic history of the sequence. 

The reports were that water condensed from the vapor phase into 10-100-/im quartz or pyrex capillaries had physical properties distinctly different from those of bulk liquid water. Confirmations came from a variety of laboratories around the world (see the August 1971 issue of Journal of Colloid Interface Science), and it was proposed that a new phase of water had been found many called this water polywater rather than the original Deijaguin term, anomalous water. There were confirming theoretical calculations (see Refs. 121, 122) Eventually, however, it was determined that the micro-amoimts of water that could be isolated from small capillaries was always contaminated by salts and other impurities leached from the walls. The nonexistence of anomalous or poly water as a new, pure phase of water was acknowledged in 1974 by Deijaguin and co-workers [123]. There is a mass of fascinating anecdotal history omitted here for lack of space but told very well by Frank [124]. 

A solid, by definition, is a portion of matter that is rigid and resists stress. Although the surface of a solid must, in principle, be characterized by surface free energy, it is evident that the usual methods of capillarity are not very useful since they depend on measurements of equilibrium surface properties given by Laplace s equation (Eq. II-7). Since a solid deforms in an elastic manner, its shape will be determined more by its past history than by surface tension forces. 

The immobility of the surface atoms of a refractory solid has the consequence that the surface energy and other physical properties depend greatly on the immediate history of the material. A clean cleavage surface of a crystal will have a different (and probably lower) surface energy than a ground, abraded, heat-treated or polished surface of the same material. 

Actual crystal planes tend to be incomplete and imperfect in many ways. Nonequilibrium surface stresses may be relieved by surface imperfections such as overgrowths, incomplete planes, steps, and dislocations (see below) as illustrated in Fig. VII-5 [98, 99]. The distribution of such features depends on the past history of the material, including the presence of adsorbing impurities [100]. Finally, for sufficiently small crystals (1-10 nm in dimension), quantum-mechanical effects may alter various physical (e.g., optical) properties [101]. 

The definition above is a particularly restrictive description of a nanocrystal, and necessarily limits die focus of diis brief review to studies of nanocrystals which are of relevance to chemical physics. Many nanoparticles, particularly oxides, prepared dirough die sol-gel niediod are not included in diis discussion as dieir internal stmcture is amorjihous and hydrated. Neverdieless, diey are important nanoniaterials several textbooks deal widi dieir syndiesis and properties [4, 5]. The material science community has also contributed to die general area of nanocrystals however, for most of dieir applications it is not necessary to prepare fully isolated nanocrystals widi well defined surface chemistry. A good discussion of die goals and progress can be found in references [6, 7, 8 and 9]. Finally, diere is a rich history in gas-phase chemical physics of die study of clusters and size-dependent evaluations of dieir behaviour. This topic is not addressed here, but covered instead in chapter C1.1, Clusters and nanoscale stmctures, in diis same volume. 

Nomenclature is the compilation of descriptions of things and technical terms in a special field of knowledge, the vocabulary ofa technical language. In the history of chemistry, a systematic nomenclature became significant only rather late. In the early times of alchemy, the properties of the substance or its appearance played a major role in giving a compound a name. Libavius was the first person who tried to fix some kind of nomenclature in Alckeinia in 1,597. In essence, he gave names to chemical equipment and processes (methods, names that are often still valid in our times. 

The next step towards increasing the accuracy in estimating molecular properties is to use different contributions for atoms in different hybridi2ation states. This simple extension is sufficient to reproduce mean molecular polarizabilities to within 1-3 % of the experimental value. The estimation of mean molecular polarizabilities from atomic refractions has a long history, dating back to around 1911 [7], Miller and Sav-chik were the first to propose a method that considered atom hybridization in which each atom is characterized by its state of atomic hybridization [8]. They derived a formula for calculating these contributions on the basis of a theoretical interpretation of variational perturbation results and on the basis of molecular orbital theory. 

The use of group contribution methods for the estimation of properties of pure gases and Uquids [20, 21] and of phase equilibria [22] also has a long history in chemical engineering. 

Preparation and properties of nitronium salts The first preparation of a nitronium salt by Hantzsch, who isolated the perchlorate mixed with hydroxonium perchlorate, and some of the subsequent history of these salts has already been recounted ( 2.3.1). 

Activated carbons contain chemisorbed oxygen in varying amounts unless special cate is taken to eliminate it. Desired adsorption properties often depend upon the amount and type of chemisorbed oxygen species on the surface. Therefore, the adsorption properties of an activated carbon adsorbent depend on its prior temperature and oxygen-exposure history. In contrast, molecular sieve 2eohtes and other oxide adsorbents are not affected by oxidi2ing or reducing conditions. 

Although the use of simple diluents and adulterants almost certainly predates recorded history, the use of fillers to modify the properties of a composition can be traced as far back as eady Roman times, when artisans used ground marble in lime plaster, frescoes, and po22olanic mortar. The use of fillers in paper and paper coatings made its appearance in the mid-nineteenth century. Functional fillers, which introduce new properties into a composition rather than modify pre-existing properties, were commercially developed eady in the twentieth century when Goodrich added carbon black to mbber and Baekeland formulated phenol— formaldehyde plastics with wood dour. 

Polymer Composition. The piopeities of foamed plastics aie influenced both by the foam stmctuie and, to a gieatei extent, by the piopeities of the parent polymer. The polymer phase description must include the additives present in that phase as well. The condition or state of the polymer phase (orientation, crystallinity, previous thermal history), as well as its chemical composition, determines the properties of that phase. The polymer state and cell geometry are intimately related because they are determined by common forces exerted during the expansion and stabilization of the foam. 

Some representative backbone stmctures of PQs and PPQs and their T data are given in Table 1. As in other amorphous polymers, the Ts of PQs and PPQs are controlled essentially by the chemical stmcture, molecular weight, and thermal history. Several synthetic routes have been investigated to increase the T and also to improve the processibiUty of PPQ (71). Some properties of PPQ based on 2,3-di(3,4-diaminophenyl)quinoxaline and those of l,l-dichloro-2,2-bis(3,4-diaminophenyl)ethylene are summarized in Table 2. 

Hardness of the aimealed metals covers a wide range. Rhodium (up to 40%), iridium (up to 30%), and mthenium (up to 10%) are often used to harden platinum and palladium whose intrinsic hardness and tensile strength are too low for many intended appHcations. Many of the properties of rhodium and indium. Group 9 metals, are intermediate between those of Group 8 and Group 10. The mechanical and many other properties of the PGMs depend on the physical form, history, and purity of a particular metal sample. For example, electrodeposited platinum is much harder than wrought metal. 

---