Cellulose scanning electron micrograph

Fig. 5. Scanning electron micrographs of hoUow fiber dialysis membranes. Membranes in left panels are prepared from regenerated cellulose (Cuprophan) and those on the right from a copolymer of polyacrylonitrile. The ceUulosic materials are hydrogels and the synthetic thermoplastic forms a microreticulated open cell foam with a tight skin on the inner wall. Pictures at top are membrane cross sections those below are of the wall region. Dimensions as indicated.

The results of mechanical properties (presented later in this section) showed that up to 20 phr, the biofillers showed superior strength and elongation behavior than CB, cellulose being the best. After 30 phr the mechanical properties of biocomposites deteriorated because of the poor compatibility of hydrophilic biopolymers with hydrophobic natural rubber(results not shown). While increasing quantity of CB in composites leads to constant increase in the mechanical properties. Scanning electron micrographs revealed presence of polymer-filler adhesion in case of biocomposites at 20 phr. 

Figure 2.29 Scanning electron micrographs at approximately the same magnification of four microporous membranes having approximately the same particle retention, (a) Nuclepore (polycarbonate) nucleation track membrane (b) Celgard (polyethylene) expanded film membrane (c) Millipore cellulose acetate/cellulose nitrate phase separation membrane made by water vapor imbibition (Courtesy of Millipore Corporation, Billerica, MA) (d) anisotropic polysulfone membrane made by the Loeb-Sourirajan phase separation process...

FIGURE 20.4 Scanning electron micrographs (SEM) micrographs of the cross section of a cellulose acetate membrane of 0.45 pm pore size after being used for beer CMF experiments. A dense fouling layer is observed on the membrane surface. (From Moraru, C.I., Optimization and membrane processes with applications in the food industry Beer microfiltration. PhD thesis. University Dunarea de Jos Galati, Romania, 1999.)... 

Figure 2. The technical nature of wood tissue. (A) Scanning electron micrograph (SEM) of the surface of a softwood resulting from a cut directed perpendicular to the tree axis. This view is known tecnnicallu as the transverse or cross-sectional plane. (B) Schematic showing the location of the major constituents of wood chemistry. (C) Transmission electron micrograph (TEM) of the transverse section of a white spruce wood lignin skeleton that was prepared by removing cellulose and hemicelluloses with hydrofluoric add. Key L, lumen W, wall and ML, middle lamella. (Reproduced with permission from Ref. 38. Copyright 1974, Forest Products...

Figure 10. Scanning electron micrograph of a composite of cellulose powder-lignin powder mixture. The hig, fibrous cellulose particle (right) appears to be bonded to the big amorphous lignin particle (left). A split in the cellulose particle suggests that bonding between lignin and cellulose particles was stronger than the tensile strength of cdlulose perpendicular to the fiber axis (12A).

Gel-permeation chromatography" is used to compare the pore structure of jute, scoured jute and purified cotton cellulose. Both native and scoured jute have shown greater pore volumes than cotton. The effects of alkali and acid treatment on the mechanical properties of coir fibers are reported." Scanning electron micrographs of the fractured surfaces of the fibers have revealed extensive fibrillation. Tenacity and extension-at-break decrease with chemical treatment and ultraviolet radiation, whereas an increase in initial modulus and crystallinity is observed with alkali treatment. FTIR spectroscopy shows that the major structural changes that occur when coir fibers are heated isothermally in an air oven (at 100, 150 and 200 °C for 1 h) are attributable to oxidation, dehydration and depolymerization of the cellulose component. 

Figure 5 Hierarchical microstructure of a linen fibre (a) from cellulose chains to the fibre and (b) a scanning electron micrograph showing the ultimate cells bundled in fibres...

Figure 1.17 Scanning electron micrographs of membrane cross sections prepared from three different polymer-solvent systems by precipitation in water (a) 12% cellulose acetate in DMAc (b) 12% polyamide in DMSO (c) 12% polysulfone In DMF.

Fig. 2 (adapted from [23]). Scanning electron micrographs of (a) cellulose-coated commercial AC used in Adsorba 300C haemoperfusion column (Gambro, Sweden) and (b) unooated AC produced from phenol-formaldehyde resin (MAST Carbon Ltd., Guildford, Surrey, UK). 

Figure 10. Scanning electron micrograph of a cross-section (top) of a diquaternary ammonium cellulose prepared by reaction of a DEAE cellulose (2.57% N) with dllodopentane and exchanged to thiocyanate form (100% conversion) and EDAX (bottom) showing distribution of s throughout fiber.

Figure 9.11 Scanning electron micrographs of slow drying (stagnant air) versus fast drying (impinging jet of air) coatings of cellulose acetate in mixed acetone-water solvent...

Fig. 53. Scanning electron micrograph of the composite acetylated rayon fiber-cellulose acetate matrix.

Fig. 55. Scanning electron micrograph of a cellulose-cellulose con osite. (A) and (B) Rayon fiber-cellulose acetate composites, after regeneration of cellulose acetate in aUcahne conditions, showing the poor quality of the interface. (C) and (D) Acetylated rayon fiber-ceUulose acetate composites after coregeneration in alkaline conditions, showing disappearance of the interfece.

FIGURE 45.4 Scanning electron micrograph of cellulose esters (CAB381-20) matrix microspheres of size 250-355 pm prepared by O1/O2 emulsion solvent evaporation method. (Reproduced from Obeidat, W.M. and Price, J.C., J. MicroencapsuL, 21(1), 47, 2004.)... 

Fig. 8. Scanning electron micrographs of the bottom surface of cellulose acetate membranes cast from a solution of acetone (volatile solvent) and 2-methyl-2,4-pentanediol (nonvolatile solvent). The evaporation time before the structure is fixed by immersion in water is shown. Reprinted from Ref. 23, Cop3Tight 1974, with permission from Elsevier Science.

Figure 2.7 Scanning electron micrographs (SEM) of bacterial cellulose produced in (a) agitated and (b) static cultures. Reproduced with permission from [38].

Figure 1. High magnification scanning electron micrographs of untreated cellulose substrates and substrates with retained xylan (a) dissolving pulp reference, (b) lyocell reference, (c) dissolving pulp with xylan (24.4%), and (d) lyocell with xylan (16.8%). Magnification 2000x. Weight increase of substrates corresponding to amount of retained xylan is shown in parenthesis.

Figure 3.7 Scanning electron micrograph of a bacterial cellulose pellicle.

Figure I. Scanning electron micrographs of A. xylinum and cellulose fibril.

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