Geotextiles chemical bonding

Chemical bonding. A binder such as glue, rubber, casein, latex, cellulose derivative, or a synthetic resin is used for bonding the filaments or short fibres together and these materials are known as chemically or adhesive bonded nonwoven geotextiles. 

Both woven and nonwoven geotextiles are made from four polymeric materials (polyamide, polyester, polyethylene, and polypropylene) and natural materials. Woven geotextiles may be fabricated with monofilament yams, muldfilament yams, or a combination of each. Nonwoven geotextiles are bonded by one of the several methods thermal, mechanical, or chemical. With the many combinations of materials and processes, it is not difficult to see that the physical properties of geotextiles will vary greatiy among products (Yeo, 2008). 

Nonwoven geotextiles. Nonwoven fabrics are defined as a sheet, web, or batt of directionally or randomly oriented fibres/filaments, bonded either by friction, and/or cohesion, and/or adhesion. In general, nonwoven fabric formation can be considered as a two-step process web formation (aligning the fibres with certain orientation characteristics) and bonding these fibres by mechanical, thermal, or chemical means. This two-step process has formed the classification of nonwoven structures, i.e. carded, airlaid, spunlaid, meltblown, needlepunched, hydroentangled, adhesive bonded, thermal bonded, stitch bonded, etc. Some of the important processes that are used for the manufacture of nonwoven geotextiles are discussed below. 

Nonwoven geotextiles are composed of directionally or randomly oriented fibers which are mechanically (needle punching), chemically, or thermally bonded into a loose web. 

The third stage in this process consists of bonding the web into a geotextile possessing the physical and mechanical characteristics that approach those of the finished product. The bonding process can be done using mechanical, thermal or chemical means. These are the principle operations of this stage of the process ... 

After bonding of the geotextile using mechanical means, some thermal or chemical processes, as shown in Section 3.2.1, can be applied to give the product its final physical, mechanical and hydraulic properties. Once the product has attained its final characteristics, it will be inspected, cut and packaged. These procedures can be more or less automated, as was explained in the previous section. 

Nonwoven geotextiles are produced mechanically or chemically, or by heat-bonding fibers together to form a stable network. Nonwoven geotextiles have higher flexibility and movement than do woven geotextiles. Because of this, they are ideal for use in separation applications where the earthen base may have irregularities to which the nonwoven can mold. The thickness and puncture resistance of a... 

---