**3.3. Measurement of bending property**

jute fibre has some of the unique features which others do not have, like high moisture regain, coarseness, biodegradability, high surface roughness, etc. Following are some of the important

Tensile is one of the most important properties to be evaluated for any textile material. To evaluate this property, all the samples are tested for tensile strip test on Universal Tensile Tester (UTM) following the standard test method ASTM D1682-64 under standard atmospheric condition (65 ± 2% relative humidity and 27 ± 2 °C temperature). For needle-punched nonwo‐ ven, the sample specimen width is 25.4 mm and the gauge length is to be set at 75 mm. The strain rate has to be set in such a way that the failure of the samples occurs between a timespan of 20 ± 3 seconds, depending on the type of fabric samples. Maximum load (in terms of Newton unit) breaking extension in percentage have to be recorded. From the value of breaking

> = ´ ´ <sup>100</sup> *BL <sup>T</sup> SW FW*

where, T – fabric tenacity (cN/tex); BL – breaking load (N); SW – specimen width (mm); and

The initial modulus and secant modulus have also been calculated from the respective stress–

The jute needle-punched nonwoven fabrics are porous in nature and hence they are permeable. To study the air permeability property, this test is carried out. Evaluation of air permeability nonwoven fabric samples can be done using any reliable air permeability tester (Shirley Air Permeability Tester). The results are expressed as the units of volume of air in cubic-centimetre, passed per second, through one square centimetre of fabric at a pressure difference of 10 mm or 1 cm head of water. But in some cases, the range of flow metre available in the instrument may not achieve the high flow rate required for this specific pressure difference. In such a case, superimposed layers of fabric on one another have been tested at a time and the flow rate reading for a single layer was calculated by multiplying the result by number of layers. Air permeability value was calculated by dividing the flow rate reading in cc/sec at 1 cm pressure

permeability (SAP) value was used to compare the permeability of different fabric samples.

= ´ <sup>0</sup> *SAP AP T*

s; and T0, the mean thickness in meter at 1.55 kPa pressure of the fabric sample. This test is

The SAP values of all the samples were determined from the following formula [10]:

(1 inch2

/s/cm; AP, the air permeability in cm3

). Sectional air

/cm2 /

tests to be carried out to suit its suitability in some of those application areas.

load, the tenacity values are calculated by the following formula [9]:

head of water by the test area, which is in this instrument 5.07 cm2

where, SAP is the sectional air permeability in cm3

).

**3.1. Measurement of tensile property**

FW – fabric weight (g/m2

**3.2. Measurement of air permeability**

strain curves.

280 Non-woven Fabrics

The stiffness of the jute needle-punched nonwoven textile fabric is used for technical textile, and samples are investigated by examining different bending parameters, for example, flexural rigidity and bending modulus, at 65 ± 2% relative humidity and 27 ± 2 °C temperature after conditioning the sample for 24 hours. The flexural rigidity of the fabric samples was deter‐ mined by measuring the bending length following the standard cantilever principle by using the stiffness tester. The average value was calculated from 10 specimens in both warp and weft directions of the woven fabrics. Similarly for nonwoven samples both machine and cross directions of the fabric specimens were considered. The specimen size of each sample was 150 mm x 25 mm for higher flexible fabrics. The bending length was measured directly from the instrument. Flexural rigidity was calculated from the following formula [9]:

$$FR = \frac{WC^3}{10^4} \times 9.81$$

where FR = flexural rigidity in Newton in Newton-cm; W = fabric area density (g/m2 ); and C = bending length in cm.

For bending modulus, the thickness of each sample was measured under the pressure of 1 lb/ in2 by using a thickness tester (ASTM D5199-917 ). The bending modulus of the samples was determined from the following formula:

$$\mathcal{B}M = \frac{12G}{\mathcal{g}^3}$$

where BM= bending modulus in Newton/cm2 ; G= g = thickness (cm) of sample at 1 lb/in2 .

In case of thick and rigid fabric, the above method of measurement of bending length is not valid. In such a case, a loop method is suggested [11].

#### **3.4. Design measurement of water imbibition property**

For the measurement of water retention characteristics, the samples were cut into equal size of 4 cm x 4 cm and weight under the following natural atmospheric conditions, for example, dry bulb temperature 87°F, wet bulb temperature 81°F, and relative humidity 77%.

The samples are soaked in distilled water for about 48 hours. Later, all these samples are hung in free air for about 40 minutes to drip out the excess water absorbed by the samples. These samples are then kept on a blotting paper for 5 minutes to absorb further excess water present on the surface of the samples. Now, the weight of the wet samples is taken to find the absorb‐ ency of water by using the following formula [9]:

$$WA = \frac{W\_{\text{net}} - W\_{\text{dry}}}{W\_{\text{dry}}} \times 100$$

where WA is water absorbency in percentage, Wwet is the weight of fabric in wet condition, and Wdry is the weight of the fabric in dry condition.

Release of moisture with respect to time are determined for all samples unit they achieved the constant weight.

#### **3.5. Compression**

Compression is one of the important properties to be measured to evaluate the performance of the needle-punched nonwoven jute fabric for some specific application point of view like carpet, geotextile, etc. The initial thickness, compression, thickness loss, and compression resilience can be calculated from the compression and decompression curves. For measuring these properties, a thickness tester is required. The pressure foot area is 5.067 cm2 (diameter = ϕ2.54 cm). The dial gauge with a least count of 0.01 mm and maximum displacement of 10.5 mm is attached to the thickness tester. The compression properties are studied under a pressure range between 1.55 kPa and 51.89 kPa.

The initial thickness of the needle-punched fabrics is observed under the pressure of 1.55 kPa. The corresponding thickness values are observed from the dial gauge for each corresponding load of 1.962 N. A delay of 30 seconds is given between the previous and next load applied. Similarly, 30 seconds delay was also allowed during the decompression cycle at every individual load of 1.962 N. These compression and recovery thickness values for correspond‐ ing pressure values are used to plot the compression–recovery curves.

The percentage compression, percentage thickness loss, and percentage compression resilience are estimated using the following three relationships [12]:

$$C = \frac{T\_0 - T\_1}{T\_0} \times 100$$

$$TL = \frac{T\_0 - T\_{21}}{T\_0} \times 100$$

$$CR = \frac{W\_\odot}{W\_\odot} \times 100$$

where C is the compression in percentage, TL is the thickness loss in percentage, CR is the compression resilience in percentage, T0 is the initial thickness, T1 is the thickness at maximum pressure, T2 is the recovered thickness, Wc is the work done during compression, and Wc′ is the work done during the recovery process.

The average of 10 readings from different places for each sample need to be considered. The coefficient of variation should be within 6%, if not a greater number of readings is necessary. All these tests must be carried out in the standard atmospheric condition of 65 ± 2% RH and 20 ± 2°C. The fabrics are conditioned for 24 hours in the above mentioned atmospheric conditions before testing.
