Forming process 90/0 fabric orientation

Air-laid nonwovens n. Fabrics made by an air-forming process. The fibers are distributed by air currents to give a random orientation within the web and a fabric with isotropic properties. 

Other phenomena have been observed during the forming process (Lin et al., 2007 Boisse et al., 2011 Mohammed et al., 2000), such as the variation of the volume fraction of fibres on the permeability of the resulted textile stmcture, the influence of the local orientation of multifilaments yams on the global rigidity of the fabric, and the localization of plies on the fabric surface. 

Lankhorst Pure Composites produces and sells PURE . This product is made of different grades of polypropylene that are combined using a co-extrusion process. The core is a highly oriented, high modulus PP tape which is skinned with a specially formulated PP that allows welding of the tapes together. Parts are usually made from semifinished products in the form of fabrics and are found in antiballistic applications as well as automotive, construction and consumer products, such as suitcases and sporting apparel. 

An unusual feature of fabricating HMW-HDPE into film is the length the molten polyethylene travels during the film-forming process before the bubble is inflated. The bubble shape is illustrated in Figure 6.17 and is referred to as high-stalk extrusion. This extrusion shape is used in order to produce film with more balanced orientation (more balanced properties in the MD and TD direction). After the melt exits the die, the melt is drawn down by about a factor of 20 in the machine direction before the bubble is inflated with a blow-up ratio of 4, i.e., the diameter of the bubble is four times the diameter of the die. Hence, the melt is drawn down by a factor of 80. Consequently, a final film thickness of 0.5 mils is obtained with a die... 

Textile technology is used to mechanically or aerodynamicaHy arrange textile fibers into preferentially oriented webs. Fabrics produced by these systems are referred to as dry-laid nonwovens. Dry-laid nonwovens are manufactured with machinery associated with staple fiber processing, such as cards and gametts, which are designed to manipulate preformed fibers in the dry state. Also included in this category are nonwovens made from filaments in the form of tow, and fabrics composed of staple fibers and stitching filaments or yams, ie, stitchbonded nonwovens. 

We use the spinning process to make polymer fibers and filaments that can be converted into fabrics and cordage. During fiber spinning, molten polymer is pumped through holes in a plate to form a multiplicity of strands that are rapidly stretched and cooled. The finished product comprising oriented fibers is either wound up on spools or converted directly into a non-woven fabric. 

Having said this, it was felt therefore that there is a need for a book addressing analysis and characterisation of polymers from the point of view of what we wish to call the primary analytical question. Many excellent textbooks and reference works exist which address one or more individual analytical techniques, see, for example, references [1-10]. These books form the basis of the knowledge of the technique expert. They also contain many excellent and varied examples on successful applications of analytical techniques to polymer analysis and characterisation. There are also books which address the multitude of analytical techniques applied in polymer analysis, see, for example, references [11-24], However, a synthetic chemist may wish to know the constitution of his/her polymer chain, a material scientist may want to find out the reasons why a fabricated sample had failed. What technique is best or optimal to study chain constitution will depend on the situation. Polymer failure may result from morphological features, which needs to be avoided, a contaminant, a surface property degradation, etc. When a sample has been processed, e.g., a film blown, molecular orientation may be the key parameter to be studied. A formulation scientist may wish to know why an additive from a different supplier performs differently. It is from such points of view that polymer analysis and characterisation is addressed in this book. 

In the Z-type deposition film, however, the long spacing of 7.2 nm did not agree with the predicted value of 3.9 nm rather, it was the same value as that of the Y-type deposition film. This result demonstrates that the Z-type film does not possess the Z-type layer structure but the Y-type layer structure. It should be assumed that the molecules were turned over in the deposition process and formed the Y-type layer structure, since the Z-type layer structure in which a hydrophilic group touches on a hydrophobic group is unstable. The conclusion from the examination of long spacings well supports molecular orientations in the LB films determined from the linear Stark effect measurements. From the linear Stark effect and the X-ray diffraction measurements, it is demonstrated that the hetero Y-type deposition method is useful for fabrication of stable noncentrosymmetric LB films. 

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