Extract fibers

A pilot plant ia India has been estabUshed to extract fiber, pulp, and juice from the leaves of sisal plants. The fiber is sold direcdy or used to manufacture rope, the cmshed pulp is used ia paper processiag, and the juice is an excellent source of hecogenin. During a three- to five-day fermentation of the juice, partial enzymatic hydrolysis causes hecogenin to precipitate as the hemisaponin ia the form of a fine sludge. This sediment is hydrolyzed with aqueous hydrochloric acid, neutralized, and filtered. This filter cake is washed with water and extracted with alcohol. The yield of hecogenin varies between 0.05 and 0.1% by the weight of the leaf (126). 

Local Extractive Fiber-Optic Flow Cell Sample Systems... 

No complicated or expensive instrumentation is needed (although the extraction fibers have to be regarded as relatively expensive consumables)... 

TCA, was used as an internal standard. The extraction fiber of the SPME, coated with polymethylsiloxane, was exposed for 25 minutes in the headspace of the sample vial, and then injected into the injection port of the GC-MS by a Varian 8200 CX autosampler. Limit of quantification of this method was 5 ng/L. The method was linear from 5 to 250 ng/L with an overall coefficient of variation for replicate analyses of less than 13%. 

Pruned fronds 10.4tons/ha Recycled in plantation Very high By-product Vitamin E extraction, fiber-board, etc. 

A related technique, called solid-phase microextraction, uses a fused silica fiber coated with a nonvolatile polymer to extract organic analytes directly from aqueous samples or from the headspace above the samples. The analyte partitions between the fiber and the liquid phase. The analytes are then desorbed thermally in the heated injector of a gas chromatograph (see Chapter 31). The extracting fiber is mounted in a holder that is much like an ordinary syringe. This technique combines sampling and sample preconcentration in a single step. 

A comparison of the results of Biro and Szent-Gyorgyi (1949) with those of Korey (1950) reveals a similar parallehsm between breakdown and structural changes in the protein. In these experiments, it is true, the measured hydrolysis rate does not represent an initial velocity, but the second of the conditions under (ii) above is fulfilled, for the preparations were as free to contract in the contraction experiments as in the enzymatic. The optimum ATP concentration found for shortening (Korey, 1950) and for breakdown (Biro and Szent-Gyorgyi, 1949) are both 10 for extracted fiber bundles at 20°C. The fact that this value is higher than for the isolated model fiber may be only an apparent discrepancy, for the effective concentration of ATP in the interior of the fiber bundle is appreciably lower than that in the bath. 

FIGURE 6.1 Images of raw silk fibers from commercial courses to show the fibroin fibers before (left) and after (right) extraction. Fibers are approximately 5 7 jun in diameter insert is lower magnification. 

To obtain fibers, stems are harvested and dew-retted, and the fibers are then mechanically processed to extract fibers from the nonfiber woody materials... 

Abstract Pineapple leaf fibers (PALF) have long been known as textile materials in many countries. Despite being mechanically excellent and environmentally sound, PALF are the least-studied natural fibers, especially for reinforcing composites. This article presents a survey of research works carried out on PALF and PALF-reinforced composites. It reviews PALF extraction, fiber characterization, and PALF applications, modification of PALF, and manufacture and properties of PALF-reinforced composites. With increasing importance of pineapple and pineapple plantation area, value-added applications of PALF as reinforcing fibers in polymer composites must be developed in order to increase resource potential of pineapple and consequently energize the utilization of PALF. 

The effect of different chemical treatments on the tensile properties of sisal fiber is shown in Table 22.1. However, there is a wide variation in the tensile strength of the treated fiber And the prime factors responsible for such variations are the age of the fiber climatic condition imder which it is grown the technique of extracting fiber from the sisal leaf precision and treatment handling techniques and finally the untreated fibers being not of the same properties to compare with the treated fiber, especially where the work was conducted in different parts of the world. Nevertheless, the tensile strength of untreated sisal fiber, cultivated at AMPRI Bhopal, Central India, over a period of 5 years, and after harvest extracted using the Raspador machine was 501.3 119.5 MPa (Table 22.2). 

In the course of these procedures, the non-cellulosic parts are removed in specific proportions and the cellulosic fibers are exposed and seperated [56]. Each method has its advantages and disadvantages in terms of the yield and quality of the extracted fibers... 

Retting time depends on the plant species. While okra bast fibers can be obtained after a duration of 15 - 30 days [14,22] it takes several months to extract fibers from corn husk by water retting [13]. The author has not been able to extract fibers from reed leaves and stalks even after two years of immersion in water tanks. 

The utilization of enzymes in the natural fiber modification field is rapidly increasing. This trend may be due to the environmentally-friendly nature of enzyme treatments as the catalyzed reactions are very specific and the performance is very focused [3]. Several enzymes have been used in order to enhance the effectiveness of extracting fibers from the agro-residue or fine-tune the properties of extracted fibers such as lowering their diameter. Xylanases, cellulases, pectinases are the enzyme types that have found more use in agro-residual fiber modification [12,13,38]. 

All bast (stem) fibers (flax, kenaf, ramie, nettle, hemp, jute) as well as hard fibers (caroa, sisal) are suitable as for reinforcing fibers for natural fiber reinforced polymer composites, if they have a high tensile modulus and sufficient tensile strength. In addition to cultivation site, type and harvest, the properties of natural fibers depend significantly on the fiber extraction method. An extraction to technical fiber grades, i.e. production of bundles with different number of single fibers, is generally sufficient for use in plastics composites. The properties of such extracted fibers may be described as follows ... 

Solid Phase Micro Extraction Fiber and Injector... 

The aim of the present study is to determine by XPS the chemical surface characteristics of different types of cotton fibers and to compare these characteristics with thermodynamic surface properties (surface energy) of the fibers, previously determined by means of inverse gas chromatography (IGC) at infinite dilution[3,4] Three types of cotton fibers of different varieties and exhibiting different maturities and wax contents are analyzed as received (raw fibers) or after having been extracted (extracted fibers) in hot ethanol for 6h. These results are compared with those previously obtained by inverse gas chromatography analysis. 

Cotton samples were analysed as reeeived (raw fibers) or after having been cleaned (extracted fibers) with hot 95% ethanol using a soxhlet extractor for 6h. Waxes and other type of molecules adsorbed on the fiber surfaee are a priori easily removed by such an extraction [11]... 

A representative low resolution survey XPS spectrum and a corresponding high resolution spectrum of the carbon Cls region for the raw and extracted fibers are shown in Figure 2. 

Table 3. 0/C ratios and percentages of chemical groups (cl to c3) obtained by XPS for raw and extracted fibers as weU as for cellulose and materials(subjects) pectins.

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