Mechanical Fiber Separation Methods

Mechanical fiber separation may be carried out in different ways such as beating the fiber source with metal blades (scutching) or combing (hackling) [56]. When combined with other separation techniques, mechanical decortication, which is also known as scutching, leads to production of lighter, softer and finer fibers [8]. Although 

Another way of obtaining fibers from agricultural residues is pulping. However, using this method, the obtained fibers are 0.5 to 1.5 mm in length, which is too short to be processed in textiles, nonwoven production and some other industrial applications [7,12]. As known, aspect ratio is a major factor influencing the mechanical properties of a composite. Higher aspect ratio results in better tensile, flexural and impact 

Storage of field residuals may have a direct effect on the final quality of the fibers. The residuals are prone to rotting in damp state. Drying may be a practical solution to 

Fiber source Extraction method Treatment Chemicals used Enzymes used Studied characteristics Reference 

Corn husk Alkalization Enzymatic treatment Bleaching Pidpzyme Cellulase Spectrophotometry 12 

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There are several modifications of the sulfite method which are designated according to the pH of the cooking liquor (Table 7-1). For the production of chemical pulps, delignification is allowed to proceed until most of the lignin in the middle lamella is removed after which the fibers can be readily separated from each other. Semichemical pulps are often produced by the neutral sodium sulfite method followed by mechanical fiberization of the partially delignified wood. 

The main method for fiber separation from the flax is microbiological one in which vital activity of pectin degrading microorganisms degrade pectins linking bast batches to the stalk tissues. After that the fiber can be easily detached by mechanical processing. 

Other routes to reachieving filament separation have been described and rely on mechanical or aerodynamic forces to affect separation. Figure 4 illustrates one method which utilizes a rotating deflector plane to force the filaments apart while depositing the opened filaments ia overlapping loops (25). After the splayed filaments fall to the deposition surface or forming screen, a suction from below the disposition surface holds the fiber mass in place. 

Acids and alkaUes were used to decompose the fiber to cellulose. The alkaU digester process, developed in 1899, is stiU used. Fiber glass reinforcement must be removed mechanically before the mbber can be reclaimed. A highly efficient method involves hammer mills and reel beaters to separate the fiber from the mbber an air current subsequentiy drives off the fiber. 

Preliminary research has shown that Brillouin fiber-optic sensing systems provide a possible method to detect leaks and third-party intrusion on a pipeline over distances of 25 km or more. Their intrinsic response to both temperature and mechanical strain allows for the separation of these parameters and the detection of anomalies in the scan profiles. In addition, the same sensor could be integrated into the pipeline system to detect possible ground movement relative to fixed reference points. Limited test results on surface loads associated with the intrusion of vehicles and people on a pipeline have demonstrated the sensitivity of the system and its ability to discriminate loads at different soil depths. 

Another method of producing composite hollow fibers, described by Kusuki etal. at Ube [108] and Kopp et al. at Memtec [109], is to spin double-layered fibers with a double spinneret of the type shown in Figure 3.37. This system allows different spinning solutions to be used for the outer and inner surface of the fibers and gives more precise control of the final structure. Often, two different polymers are incorporated into the same fiber. The result is a hollow fiber composite membrane equivalent to the flat sheet membrane shown in Figure 3.26. A reason for the popularity of composite hollow fiber membranes is that different polymers can be used to form the mechanically strong support and the selective layer. This can reduce the amount of selective polymer required. The tailor-made polymers developed for gas separation applications can cost as much as... 

The microfibrils, which are 10-20 nm wide, are visible in the electron microscope without pretreatment. Microfibrils are combined to greater fibrils and lamellae, which can be separated from the fibers mechanically, although their dimensions greatly depend on the method used. 

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