Property Considerations

Both prototypal questions related illustrate the need for a successhil technical service professional to have a strong understanding of the customer s apphcations and processes, within proper intellectual property considerations. This need for a thorough understanding is not always straightforward. A common example of the complications that can arise is provided from the paint (qv) industry (11). If, for instance, a calcium carbonate suppHer would like a paint manufacturer to use their material versus a competitive one, the onus is on the suppHer to show that the material can be successfully used in the paint formula of interest. However, many such formulas are held as proprietary. The technical service professional therefore does not know the components of the paint. This would lead to an unworkable situation from an evaluation standpoint save for the fact that the paint company may supply a miHbase or other intermediate form of the paint to allow a proper comparison of carbonates to be carried out. Thus mutual benefits can result and no loss of proprietary information occur. 

Structural Properties at Low Temperatures It is most convenient to classify metals by their lattice symmetiy for low temperature mechanical properties considerations. The face-centered-cubic (fee) metals and their alloys are most often used in the construc tion of cryogenic equipment. Al, Cu Ni, their alloys, and the austenitic stainless steels of the 18-8 type are fee and do not exhibit an impact duc tile-to-brittle transition at low temperatures. As a general nile, the mechanical properties of these metals with the exception of 2024-T4 aluminum, improve as the temperature is reduced. Since annealing of these metals and alloys can affect both the ultimate and yield strengths, care must be exercised under these conditions. 

Since toughness and abrasion resistance are likely to he opposing properties, considerable judgment is required in deciding where, in this series, the best prospect lies, especially if economic considerations are important. The choice is easiest at the extremes. 

This chapter has only scratched the surface of the multitude of databases and data reviews that are now available. For instance, more than 100 materials databases of many kinds are listed by Wawrousek et al. (1989), in an article published by one of the major repositories of such databases. More and more of them are accessible via the internet. The most comprehensive recent overview of Electronic access to factual materials information the state of the art is by Westbrook et al. (1995), This highly informative essay includes a taxonomy of materials information , focusing on the many different property considerations and property types which an investigator can be concerned with. Special attention is paid to mechanical properties. The authors focus also on the quality and relutbility of data, quality of source, reproducibility, evaluation status, etc., all come into this, and alarmingly. 

The future price of ionic liquids will also reflect intellectual property considerations. While the currently most frequently requested ionic liquids, the tetrafluoroborate and hexafluorophosphate ionic liquids, are all patent-free, many recently developed, new ionic liquid systems are protected by state of matter patents. Table 2.2-2 gives an overview of some examples published after 1999. 

Waste products from a number of commercial processes can be used as cheap and readily available fillers for PCM. For example, lightweight structural materials may be obtained by filling various low-viscous resins with waste materials [4, 5]. Also by adding fillers to reprocessed polymers it is possible to improve their properties considerably and thus return them to service [6]. This method of waste utilization is not only economically feasible but also serves an ecological purpose, since it will help to protect the environment from contamination. The maximum percentage of the filler should in these cases be such as to assure reliable service of the article made from the PCM under specified conditions for a specified period of time. 

Creep modeling A stress-strain diagram is a significant source of data for a material. In metals, for example, most of the needed data for mechanical property considerations are obtained from a stress-strain diagram. In plastic, however, the viscoelasticity causes an initial deformation at a specific load and temperature and is followed by a continuous increase in strain under identical test conditions until the product is either dimensionally out of tolerance or fails in rupture as a result of excessive deformation. This type of an occurrence can be explained with the aid of the Maxwell model shown in Fig. 2-24. 

Because of the large number of chemicals of actual and potential concern, the difficulties and cost of experimental determinations, and scientific interest in elucidating the fundamental molecular determinants of physical-chemical properties, considerable effort has been devoted to generating quantitative structure-property relationships (QSPRs). This concept of structure-property relationships or structure-activity relationships (QSARs) is based on observations of linear free-energy relationships, and usually takes the form of a plot or regression of the property of interest as a function of an appropriate molecular descriptor which can be calculated using only a knowledge of molecular structure or a readily accessible molecular property. 

Wilk, G. D. Wallace, R. M. Anthony, J. M. 2001. High-k gate dielectrics current status and materials properties considerations. J. Appl. Phys. 89 5243-5275. 

Various astoichiometric components (hydrogen, carbon, and others, for example, silicium and aluminum) present may interact with localized and nearly free electrons to differing extents. According to the localized free electron interplay model of metal catalysts developed by Knor 163, 164) the ratio of the two types of electrons may influence the catalytic properties considerably. For example, a subsurface proton attracts nearly free electrons and thus uncovers some localized orbitals. Carbon may interact first with localized electrons 164). This may be one of the reasons why their effects are of opposite character. The collective efforts of catalytic and surface chemists are necessary to bring some clarity to the multitude of problems arising here. 

The values given here are for resins with relatively low levels of additives. Resins with fillers or low molecular weight processing aids can have physical properties considerably different from these... 

Lipinski, C.A. Integration of physicochemical property considerations into the design of combinatorial libraries. Pharm. Nears 2002, 9, 195-202. 

Chain extenders Diols and diamines are generally used as chain extenders in PU industry and choice of chain extender influences elastomer properties considerably. The standard diol chain extender used for the synthesis of PU elastomer is 1,4-butane diol (BDO). Compared with a diol, better physical properties usually result when a diamine is employed as an extender. This is probably due to the introduction of urea linkages which enter into strong hydrogen bonded interactions. A diamine is usually chosen as the chain extender when a relatively unsymmetrical diisocyanate is employed. Diamines also function as efficient catalysts in addition to chain extenders. 

The charge of radical ions modifies their properties considerably from those of ordinary radicals. Because dimerization could form a new bond only at the expense of bringing together two like charges in the same molecule, radical ions are much more stable in solution than radicals, and it is possible to prepare stable solutions of many of them. The radical ions are readily studied spectroscopically, electron resonance being particularly fruitful. 

A good example for testing the applicability of our approach is the 13-decay of the odd-proton (Z=37) nucleus Rb to the odd-neutron (N=61) daughter Sr. As was shown in IPFE84], even from a rather time-consuming spectroscopic investigation of 9 Rb decay at OSTIS, resulting in g.s. band properties considerably improved over those reported in an earlier... 

The basic electrical properties of polyurethanes are good, but the polymer s tendency to absorb moisture can change the properties considerably. Polyurethanes are therefore not normally used as electrical insulators. They can be used in potting and encapsulating applications. Any applications involving mains power must be evaluated and approved by the relevant local electrical authority before use in the application. 

The addition of small amounts of fluorinated polyols to conventional aqueous polyurethane coatings can improve their water resistance and mechanical properties considerably 47 FEVE resins can be applied as water-based coatings and cured at 160°C (320°F) for 25 min to produce coatings with high gloss and good water and weather resistance.48 They may also be cured with water-based hardeners.49... 

Of all organic polymers used to produce insulation materials, glyptal and phenol-formaldehyde polymers are the most thermal resistant. They can function for a long time in electrotechnical devices at temperatures up to 130 °C. At higher temperatures insulation from organic polymers bums. Its dielectric properties considerably decrease, because the carbon formed is a good conductor. 

Although specific macromolecules have evolved to provide these functions in life on Earth, it is possible that some or all of these functions might be provided by monomers or by different macromolecules in other forms of life. However, all things are not possible, as the physicochemical characteristics of macromolecules conferred by their molecular structures inherently limit their functional properties. Consideration of alternative macromolecules to serve these functions must be realistic in terms of structure-function relationships of particular macromolecules. 

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