Fibrils reinforcing

Most commercial systems like Mustang from Pall and Sartobind from Sartorius make use of functionalized microporous membranes. The fibrils reinforced membranes are (pleated) layered around a porous core. The feed is forced to permeate through the membranes in radial direction. This approach results in high area to volume ratio. The 3M and Mosaic Systems approach is different. Instead of functionalization of a porous support they make use of already functionalized beads, which are embedded in a porous support. In this approach, the beads are responsible for the capacity and selectivity where the porous matrix controls the hydrodynamics. The 3M modules consist of stacked flat sheet or pleated membranes, while Mosaic Systems makes use of porous fibers in which the active particles are embedded (Figure 3.23). 

PFSA lonomer with PTFE Fibril Reinforcement Asahi Glass Flemion.789... 

FIGURE 27.41 (A) Schematic representation of a fibril-reinforced membrane and (B) a cross-sectional image after tearing. (Reproduced... 

FIGURE 27.42 Fabrication of PTFE fibril-reinforced Flemion. (Reproduced from Nakao, M. and Yoshitake, M., in W. Vielstich, H.A. Gasteiger, and A. Lamm (Eds.), Handbook of Fuel Cells Fundamentals, Technology and Applications, Vol. 3, J. Wiley Sons, Chichester, 2003. With permission.)... 

In polymeric composites, in the course of mold processing LCPs are oriented in the direction of flow. Thereby fibrils are formed. These fibrils reinforce the matrix polymer. This type of composite is addressed as an in situ composite. ... 

Zimmermann, T., Pohler, E., Schwaller, P. Mechanical and morphological properties of cellulose fibril reinforced nanocomposites. Adv. Eng. Mater. 7, 1156-1161 (2005)... 

AGC manufactures Flemion, which is based on a PTFE fibril reinforcement that was originally developed for chlor-alkali electrolysis. AGC has participated in the R D programs of... 

The key parameter in the preparation of a thin and flat membrane with fibril reinforcement is the uniform dispersion of the fibrils in the matrix. Furthermore, the overall flatness of the membrane is important for coating the electrodes. AGC s new preparation method is disclosed in European Patent EP1139472. " 5 A precursor polymer and PTFE powder are... 

S. Hommura, Y. Kunisa, 1. Terada, M. Yoshitake, Characterization of fibril reinforced membranes for fuel cells. Journal of Fluorine Chemistry 2003, 120, 151-155. 

The tensile strength of RSF/PP nanocomposite is shown in figure 3. The tensile strength of 5% rice straw fibril reinforcing PP nanocomposite was lower than PP/MAPP polymer. For the RSF/PP nanocomp)osite, the tensile strength increased with increasing cycle time from 10 min to 30 min at 180 °C. And the maximum value of tensile strength was 31.2 Mpa that appeared at the conditions of 190 °C, 20 min. 

Dentin is a bone-like tissue, consisting of collagen fibrils reinforced with carbonated hydroxyapatite particles. It constitutes the body of teeth and is covered by a hard enamel layer. It has long been used by humans as a material in the form of ivory. Given the function of teeth, the design of the dentine structure needs to sustain many years of extreme loads without any repair mechanism similar to bone remodeling. As a consequence, the dentin stmcture is likely to be very well adapted... 

It should be noted that there is not simply an addition of thermotropic LCPs into fiber-reinforced plastics to get in situ hybrid composites. Bafna et al. used glass fibers to decrease the anisotropy of LCP fibril-reinforced polyetherimide [136]. He et al. improved the processability and mechanical performances of glass fiber-reinforced polypropylene by the addition of LCPs [159]. However, these two works did not actively and purposely generate a reinforced composite with the reinforcements having their diameters at two orders of magnitude. The key point for in situ hybrid composites is the formation of LCP fibrils in the material system. As a combination of in situ composite and hybrid fiber reinforcing, the fabrication of in situ hybrid composites utilizes fabrication... 

Crystal structures of micro fibril reinforced polymer-polymer composites... 

Several studies on the dynamic mechanical analysis of synthetic and natural fiber reinforced PP composites [74-77] were reported in the literature. Lopez et al [78] reported that the incorporation of the PET fibrils separately into the PP matrix increased the storage modulus (stiffness). They also reported a decrease in the tan values of the resultant composite in comparison with PP. Li et al [73] studied the d5mamic mechanical properties of a composite where in situ generated PA6 fibrils reinforced the PP matrix. The glass transition temperature of PP was found to be higher in the case of PP/PA6 in situ composite than in a neat PP/PA6 blend. 

Three-dimensional fibril-reinforced finite element model of... 

A new kind of cellulose-based nanocomposite was also described in literature inspired by sea cucumbers [81], which like other echinoderms have the ability to reversibly alter the stiffness of their dermis in the presence of external stimuli. This stiffness modification is a defense mechanism of these organisms enabled by the nanocomposite structure of the tissue in which high aspect ratio collagen fibrils reinforce a viscoelastic matrix of fibrihllin microfibrils. The interaction between collagen fibrils is responsible for the stiffness change of the tissue, which is chemoregulated by soluble... 

Natural fibers of mineral origin are mainly used for industrial insulation purposes, whereas animal fibers are used for domestic insulation, clothing and carpets. The most beneficial fibers from the environmental point of view are those of vegetable origin. Natural fibers can be considered cellulose fibrils reinforced materials, which consist of microfibrils in an amorphous matrix of lignin and hemicellulose [28]. The cell wall in a fiber is not a homogenous membrane (Figure 4.1). 

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