Plastics represent one of the most pervasive types of materials in our society. This chapter describes the structure, formation mechanisms, and nomenclature of various classes of polymers. The applications described in this chapter span biomaterials (e.g., biodegradable medical stents, contact lenses, drug delivery), lithography, conductive polymers, polymer additives, and self-healing plastics. Though not entirely organic-based, materials used for molecular-magnet applications are also described in this chapter.
The properties of materials is governed by the interactions among its associated sub-units. This chapter will describe the bonding motifs of both crystalline and amorphous solids. Details of common archetypical crystal structures will be given, as well as introductory X-ray crystallography including space group symbolism and X-ray diffraction. Band theory is also provided, which is critical in understanding electrical conductivity and optical properties of crystalline solids. Applications such as superconductivity, fuel cells, and biomaterials are highlighted in this chapter in addition to many others, as we describe the influence of a material’s structure on its associated properties.
................................................................................................... 36 4.1 Introduction .................................................................................... 36 4.2 Objects and Methods ...................................................................... 36 4.3 Results and Discussion .................................................................. 41 4.4 Conclusion ..................................................................................... 47 Keywords ................................................................................................ 48 References ............................................................................................... 49ABSTRACTThe results of experimental studies to identify the degree of intensification of the processes of oil and gas mixtures heating in horizontal pipe due to changes in hydrodynamic regimes.
An experimental study to characterize the porosity of graphite-epoxy composite materials has been carried out.
In order to provide further evidence concerning the reliability of predicting relative protective performances of metal organic coatings by using electrochemical testing methods, some experimental results, obtained with such an approach, are shown.
Many Engineers who after their period of University training, work in design offices have had little, or no experience of corrosion and its prevention. The need to provide information of this type in order to ensure an adequate life for the structures designed, arises because of the very large cost of corrosion, the order of 5% of the GNP in developed countries, and the possibility of saving about 1% of GNP by proper application of known techniques.
An electrochemical method was developed for the study of the corrosion protection provided by primers containing inhibitor pigments, which are acting during wet exposure as the inhibitor is dissolved in water taken up by the paint layer. The method is based on the assumption that the efficacity of the inhibitor is retained even after a careful removal of the paint layer, if excessive polarization and corrosive environment is avoided during the test. The analysis of electrode impedances was found to comply with the above requirements and to permit the evaluation of the inhibitor efficiency. The coatings were applied to cold-rolled steel plates. After an adequate period of storage and wet exposure the coatings were removed with reagent grade dichloromethane. The coatings were immersed in the solvent for some hours, then the swollen layer was removed with clean linen and the plates were rinsed with the solvent and dried. This treatment was found to leave the metal surface unaltered. The measuring cell and equipment used for impedance measurements were identical to those used by Lengyel et al. (cfr. this issue). The following primers were used as model paints in this study:
In the last years the development of more and more sophisticated planning techniques, expecially in advanced sectors such as astronautics and nuclear plants, brought about more and more complex and efficient quality control procedures.
