188 ISSN 1229-9197 (print version) ISSN 1875-0052 (electronic version) Fibers and Polymers 2020, Vol.21, No.1, 188-195 Low Velocity Impact Performance and Puncture Resistance of Nonwoven Geotextiles with the Change of Process Parameters Rupayan Roy 1 *, Manali Chatterjee 2 , and S.M. Ishtiaque 1 * 1 Department of Textile Technology, Indian Institute of Technology Delhi, New Delhi 110016, India 2 Department of Jute and Fibre Technology, University of Calcutta, Ballygunge, Calcutta 700035, India (Received October 19, 2018; Revised June 24, 2019; Accepted July 11, 2019) Abstract: In the present work, an attempt has been made to study the effect of structural changes on the sustainable properties of needle punch nonwoven geotextile. There are two important process parameters, which influence the structure significantly. The parameters are punch density and depth of penetration of the needle. This research work is designed by considering the two parameters. Whereas, three-levels of each parameter taken and nine samples prepared by using two- factor three-level full factorial design. The structural analysis was carried out by an image analysis technique. All measured physical and mechanical properties of nonwovens have a strong correlation with the structural parameter. The significant effect noticed on fabric thickness, tensile strength, pore diameter, puncture resistance and impact resistance with the varying considered parameters; punch density and needle depth penetration. Keywords: Nonwoven structure, Needle-punched nonwoven, Pore diameter, Puncture resistance, Impact resistance Introduction Civil construction is one of the largest application fields of textiles. The geotextile is the main application in the segment of construction. These geotextiles are mainly made by nonwoven techniques [1,2] and contribute seventy-five percent of geotextiles used as nonwoven. The geotextiles performs several functions like separation, reinforcement, filtration, drainage etc. and their performance depends on the structural properties [3-5]. Basically, the nonwoven geotextiles are randomly oriented fibrous material are integrated thermally, chemically and mechanically depends upon the material used. The fibre laying methods are also different for different functional geotextiles [6,7]. The parallel and cross laying makes nonwoven anisotropic in nature, on the other hand, random laying makes isotropic nonwovens. The mechanical strength of nonwoven is governed by the orientation of fibres [8,9]. Many researchers have investigated the way out to evaluate the fibre orientation. Hearle and Stevenson [10,11] used a projection method for measuring the fibre orientation and fibre curl in nonwoven structure. However, these methods ignore the fact that the constituent fibres are distributed randomly in X, Y and Z planes. Roy and Ishtiaque [12] studied the fibre orientation in X, Y and Z planes by using tracer fibre technique and accordingly proposed few new indices. However, the method cannot be used for higher thickness. Jeddi et al. [13] compared the results with the image analysis technique using the two dimensional Fast Fourier transform of the image. Pourdeyhimi and Ramanathan [14] concluded that Fourier Transformation analysis is more accurate and robust over the Image Analysis. Neckář and Das [15] evaluated orientation of fibres in the carded web using tracer fibre technique to measure the frequency distribution of the angle of inclination of fibres. Nonwoven thickness plays an important role to govern the properties. Areal density and punching parameters i.e. punch density and needle penetration depth have large impact on the fabric thickness [16]. The researchers have concluded that needle punch nonwoven fabrics are thirty percent more effective than other nonwoven fibrous structure [6]. Road construction is the biggest application area for nonwoven geotextile, where the fabric needs to perform a separation function. According to the study of Tushar [17], puncture resistance is lower when the specimen is prestress. The low- velocity impact test also can be a useful parameter for the application of separation. However, the literature is silent about the impact performance of needle punched nonwoven. Therefore, the proposed work is focused to study the impact performance of needle punched nonwoven by varying the punching parameters. Further, the paper describes the some other important properties of geotextile like thickness, strength, mean flow pore size and puncture resistance. Experimental Materials Polypropylene fibre (density-0.92 g/cm 3 ) of 4.5 denier and 44 mm staple length was considered to prepare a set of 9 samples as shown in Table 1. The fibres were circular in cross section and the diameter was 0.024 mm. Preparation of Samples All samples were prepared in DILO Machines GmbH (Germany) needle punched nonwoven line. A two-factor *Corresponding author: rupayan666@gmail.com *Corresponding author: ishtiaque@textile.iitd.ac.in DOI 10.1007/s12221-020-8974-0