Biaxial fabrics

Fig. 6.4 Schematic diagrams of fabrics upon ballistic impact (a) biaxial fabric upon impact (b) triaxial fabric upon impact. ...

N. Mao, Towards objective discrimination evaluation of fabric tactile properties quantification of biaxial fabric deformations by using energy methods, in Proceedings of 14th AUTEX world textile conference, Bursa, Turkey, May 26—28, 2014. 

Reinforcements are also becoming more sophisticated. For example, Formax, the manufacturer of bespoke lightweight multiaxial reinforcements, has introduced a range of biaxial fabrics made from intermediate modulus carbon fibre. The —45 degrees/ +45 degrees biaxials have been developed for the manufacmre of structural composite parts. 

Typically, the fabrics are available in weights of 200 and 300 gsm. The new lightweight biaxial fabrics can be used for prepreg, RTM, infusion and wet layup composite processes [8]. 

Figure 13.1 (a) Biaxial fabric from Selcom Multiaxial Technology, Italy, (b) Triaxial fabric structure from Selcom Multiaxial Technology, Italy, (c) Quadriaxial hybrid fabric from Selcom Multiaxial Technology, Italy. 

A comparison of biaxial warp-knitted fabrics with conventional biaxial fabrics shows that warp-knitted fabrics have a partially higher stiffness than comparable fabrics due to the stretched reinforcement threads (Ploch, 1978). The overlapping... 

Using a combination of unidirectional and/or biaxial fabrics, the laminates provide strength in both longitudinal and transverse directions. The range of the tensile strength of PipeMedic laminates is 60—155 ksi (415—1070 MPa). 

Figure 3.5 PipeMedic laminates may be constmeted with multiple layers of unidirectional or biaxial fabrics.

Several more recent variations of the film-to-fiber approach result in direct conversion of film to fabric. The film may be embossed in a controlled pattern and subsequently drawn uniaxiaHy or biaxiaHy to produce a variety of nonwoven products (47). Addition of chemical blowing agents to the film causes fibrillation upon extmsion. Nonwovens can be formed directly from blown film using a unique radial die and control of the biaxial draw ratio (48)... 

R. Keshavaraj, R. W. Tock, and D. Haycook, Feedforward Neural Network Modeling of Biaxial Deformation of Airbag Fabrics ANTEC 95 Proceedings, SPE Technical Papers, Modeling of Polymer Properties and Processes, Boston (May 1995). 

This stretching, similar to the drawing of fibres, which promotes orientation and crystallite formation, is called biaxial orientation. It gives the film added strength and gas-barrier properties. In some processes, monoaxial (uniaxial) drawing is employed, e.g., polypropylene, which is then slit into thin strips and fabricated into heavy duty sacks, carpet backing, etc. The stenter process is used to make biaxial oriented poly(vinylidene dichloride) ("ding" film), polyester, polyamide and polypropylene films. 

Heat-shrinkable sheets (thickness 0.040 to 0.120 inch, or 1 to 3 mm) and films (thickness 0.001 to 0.020 inch or 0. 025 to 0.5 mm) are fabricated from many of the same materials as shrinkable tubing.91 They are produced by extrusion as a tube, sheet or blown film. Irradiation is done by the equipment shown in Figure 8.10. Orientation (stretching) after irradiation can be done by several methods, namely by differentially heated and driven rolls (in the machine direction) or by a tenter frame (see Figure 8.11) in the transverse direction. If desired, biaxial stretching can be done. 

EVOH have superior gas barrier properties.80 89 They are often used as the internal layer in multilayer food packaging films, blow molded rigid containers, gasoline tanks for automobiles for a variety of purposes, etc. EVOH can be fabricated by the usual melt processing methods. The barrier properties of films decrease in the presence of moisture, so multilayer with protective polypropylene (especially biaxially oriented material), low-density polyethylene, nylons, or other moisture barrier films provides films or products that are useful even with liquids. The... 

Where a clear, thermoformed product is desired, many fabricators use OPS. Because of the low elongation of general-purpose polystyrene, it is necessary to orient the sheet biaxially to obtain the required physical properties for satisfactory part trimming and end use. If there is insufficient elongation in the... 

As a result of this the manufacturers of polymers have found it necessary to exercise leadership in pioneering the methods by which their polymers are formed—sometimes to the extent that the manufacturer has himself often sold the polymer in the fabricated form. Hercules, for example, pioneered in the manufacture and sale of polypropylene resin. We soon realized, however, that the conversion of this resin to fiber and to film and to foam, would have to be done by us because of the complex technologies and large investments involved. Consequently, the resin manufacturer now finds himself selling polypropylene fiber, biaxially-oriented film, and foam—successfully too if I may be allowed to add. 

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