Textures technique

The film is fibrillated mechanically by mbbing or bmshing. Immiscible polymers, such as polyethylene or polystyrene (PS), may be added to polypropylene to promote fibrillation. Many common fiber-texturing techniques such as stuffer-box, false-twist, or knife-edge treatments improve the textile characteristics of slit-film fibers. 

Donaldson JJ (1994) Texturing Techniques. In Hsuan G and Koemer RM (eds) Proceedings of the 8th GRI Conference, Geosynthetics Resins, Formulations and Mannfacturing. Industrial Fabrics Association International (IFAI), St. Paul, USA,pp 113-122... 

A variation on the conventional technique of x-radiography is xeroradiography, where imaging is obtained by electrostatic rather than photographic means. Because of special merits such as edge enhancement and improved texture rendition, this technique has certain advantages, eg, in the study of ceramics (39). 

Acoustic Wave Sensors. Another emerging physical transduction technique involves the use of acoustic waves to detect the accumulation of species in or on a chemically sensitive film. This technique originated with the use of quartz resonators excited into thickness-shear resonance to monitor vacuum deposition of metals (11). The device is operated in an oscillator configuration. Changes in resonant frequency are simply related to the areal mass density accumulated on the crystal face. These sensors, often referred to as quartz crystal microbalances (QCMs), have been coated with chemically sensitive films to produce gas and vapor detectors (12), and have been operated in solution as Hquid-phase microbalances (13). A dual QCM that has one smooth surface and one textured surface can be used to measure both the density and viscosity of many Hquids in real time (14). 

The process is attractive for a number of reasons. Firstly, since it is a low pressure process the moulds are generally simple and relatively inexpensive. Also the moulded articles can have a very uniform thickness, can contain reinforcement, are virtually strain free and their surface can be textured if desired. The use of this moulding method is growing steadily because although the cycle times are slow compared with injection or blow moulding, it can produce very large, thick walled articles which could not be produced economically by any other technique. Wall thicknesses of 10 mm are not a problem for rotationally moulded articles. 

The phase behavior of polybibenzoates has been investigated mainly by DSC, variable-temperature x-ray diffraction, and optical microscopy. However, only the first two techniques are useful in the case of polymers with the high-molecular weights required for materials with good mechanical properties and, in such cases, revealing textures are not usually observed by optical microscopy. 

The present review shows how the microhardness technique can be used to elucidate the dependence of a variety of local deformational processes upon polymer texture and morphology. Microhardness is a rather elusive quantity, that is really a combination of other mechanical properties. It is most suitably defined in terms of the pyramid indentation test. Hardness is primarily taken as a measure of the irreversible deformation mechanisms which characterize a polymeric material, though it also involves elastic and time dependent effects which depend on microstructural details. In isotropic lamellar polymers a hardness depression from ideal values, due to the finite crystal thickness, occurs. The interlamellar non-crystalline layer introduces an additional weak component which contributes further to a lowering of the hardness value. Annealing effects and chemical etching are shown to produce, on the contrary, a significant hardening of the material. The prevalent mechanisms for plastic deformation are proposed. Anisotropy behaviour for several oriented materials is critically discussed. 

The properties of the materials were evaluated by textural and structural techniques, while the final catalysts are compared on the basis of their N20-decomposition under simulated industrial conditions for nitric acid plants. This reaction is known to be activated by Fe-species [151, 152]. 

Modification techniques for activated carhon were used to increase the removal capacity by surface adsorption and to improve the selectivity to volatile organic compounds (VOCs). Modified activated carbons (MACs) were prepared by modifying the purified activated carbon with various acids or bases. The effects of adsorption capacity and modified contents on the textural properties of the MACs were investigated. Furthermore, VOC adsorption and desorption experiments were carried out to determine the relationship between the adsorption capacity and the chemical properties of the adsorbents. High adsorption capacity for the selected VOCs was obtained over lwt%-H3P04/AC (lwt%-PA/AC). As a result, MAC was found to be very effective for VOC removal by adsorption with the potential for repeated use through desorption by simple heat treatment. 

Ein-Eh Y, Starosvetsky D (2003) Silicon texturing in alkaline media conducted under extreme negative potentials. Electrochem Sohd State Lett 6 C47-C50 G6mez H, Henriquez R, Schrebler R, Riveros G, Leinen D, Ramos-Barrado JR, Dalchiele EA (2004) A soft-solution electrochemical processing technique for preparing CdTe/n-Si(lOO) heterostructures. J Electroanal Chem 574 113-122... 

---