Fibers recoil

Several methods have been used to determine the compression strength of carbon fiber and its composites—The Loop Test [90] Single Filament in a Beam [91] Critical Length under Compression [92] Micro-compression [93,94] Fiber Recoil [95-97] Piezo Method [98,99] Raman Spectroscopy [100-102] Composite [103,104] and Mini-composite [105]. 

Miscibility or compatibility provided by the compatibilizer or TLCP itself can affect the dimensional stability of in situ composites. The feature of ultra-high modulus and low viscosity melt of a nematic liquid crystalline polymer is suitable to induce greater dimensional stability in the composites. For drawn amorphous polymers, if the formed articles are exposed to sufficiently high temperatures, the extended chains are retracted by the entropic driving force of the stretched backbone, similar to the contraction of the stretched rubber network [61,62]. The presence of filler in the extruded articles significantly reduces the total extent of recoil. This can be attributed to the orientation of the fibers in the direction of drawing, which may act as a constraint for a certain amount of polymeric material surrounding them. 

Although the proteins in skin are also composed of about 5% elastic fibers, they do not appear to affect the mechanical properties of the tissue. The elastic fibers are believed to contribute to the recoil of the skin, which gives it the ability to be wrinkle-free when external loads are removed. As humans age, the elastic fiber network of the skin is lost, and wrinkles begin to appear. The mechanical role of the elastic fibers is very different in vascular tissue, however. 

In all cases the anisotropic polymerization mixtures (10% by weight) could be used directly in the formation of dry-jet wet-spun fibers. Monofilament fibers were obtained by coagulation in water, tension dried at 150 °C and heat treated at 500-600 °C with a 30s residence time. The best fibers were obtained from the high molecular weight PBZT polymer (VII) which exhibited modulus values that ranged between 172 GPa and 207 GPa and tenacity values up to 2.4 GPa. Unfortunately, the compressive property as measured by the tensile recoil test was only 380 MPa, showing only a slight improvement over PBZT. 

Obtaining the compressive strength of a slender fiber is even more difficult than measuring its tensile strength. An indirect technique has been devised to obtain compressive strength of fibers. It is well known that the recoil of a tensile stress wave generates a compressive wave. This principle is used in the recoil compression test, which allows one to estimate the compressive strength of fibers. 

The Electronic Properties of Graphite, I. L. Spain Surface Properties of Carbon Fibers. D. VP. McKee and V. J. Mimeault The Behavior of Fission Products Captured in Graphite by Nuclear Recoil, Seishi Yajima... 

Elastic fibers endow a stroma with recoil after stretching. They are composed offibrillin with or without a central portion of elastin (Table 3.4). These two proteins are described in detail in Sect. 6.1.1 and 6.2.1). Elastic fibers are especially prominent in ligaments and... 

Neutron irradiation of materials itself is a well-established field. To study the susceptibility of materials around nuclear plants, articles are well found in journals related to nuclear materials. Irradiation in a nuclear reactor is carried out, however with some exception, the beam provided is combination of y rays and neutron beams. Therefore one should be prudent in evaluating dose. Neutron loses its energy through nuclear collision because of electric neutrality. For organic materials, neutrons can make light mass nucleus recoiled, such as hydrogen. Based on this speculation, neutron irradiation on polymer materials can be simulated by proton irradiation. For example, proton beam (30 MeV) irradiation on glass fiber reinforced epoxy was carried out and it was found that deterioration behavior was identical between proton 30 MeV and y rays [118]. It... 

Loss of Elastic Recoil in the Elastic Fiber on Oxidation by a Superoxide and Hydrogen Peroxide Generating Natural Enzyme... 

Applying what is now the consilient mechanism for hydrophobic association to the elastic fiber, the prediction became that oxidation of the elastic fiber by a natural enzyme with the biological role of producing superoxide and hydrogen peroxide would cause hydrophobic dissociation evidenced by a swelling and a loss of elastic recoil. A xanthine oxidase superoxide... 

Pulmonary emphysema is a chronic progressive disorder wherein the elastic fibers of the lung become fragmented and dysfunctional with the result of a loss of elastic recoil. One result is that the patient must consciously and forcibly exhale. A prominent proposal for the etiology of the disease has been the lack of proteinase inhibitors that would otherwise prevent proteolytic degradation of the fiber.To help study the disease, a successful animal model for pulmonary emphysema was developed in which direct instillation of the proteolytic enzyme elastase into the lung became the causative agent. ° ... 

Crasto AS, Kumar S, Recoil compression testing of advanced carbon fibers, 35th International SAMPE Symposium, 318-331, Apr 2-5, 1990. 

Dobb et al [108] used the recoil test and examined the broken filaments with SEM and obtained shear bands in high modulus MP fibers (Figure 20.23A) and kink bands in PAN based carbon fiber (Figure 20.23B). Parry and Wronski [111] show a kink band produced by 4-point loading a pultruded carbon fiber epoxy section (Figure 20.24). 

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