Preparation Techniques and Property Evaluations of Highly Air Permeable Needle-Punched Geotextiles

Geotextiles are made of polymers, and their conjunction with different processes and materials can provide geotextiles with desirable characteristics and functions, such as filtration, separation, and drainage, and thereby meets the environmental requirements. Chemical resistant and mechanical strong polymers, including polyester (PET) and polypropylene (PP), are thus used to prolong the service life of the products made by such materials. This study proposes highly air permeable geotextiles that are made with different thicknesses and various needle punching speeds, and the influences of these two variables over the pore structure and mechanical properties are then examined. PET fibers, PP fibers, and recycled Kevlar fibers are blended, followed by being needle punched with differing spaces and speeds to form geotextiles with various thicknesses and porosities. The textiles are then evaluated for their mechanical strength and porosity. The test results show that a thickness of 4.5 cm and 1.5 cm demonstrate an influence on the tensile strength of the geotextiles, which is ascribed to the webs that are incompletely needle punched. However, the excessive needle punching speed corresponding to a thickness of 0.2 cm results in a decrease in tensile strength, but there is also an increase in the porosity of the geotextiles.