1 Enhancement of tensile strength and biodegradation resistance of jute Materials Science Centre IIT Kharagpur Debasis Roy, Prosenjit Saha, Suvendu Manna

Reagent preparation Phenol-formaldehyde (PF) resin Vegetable oil emulsion Alkaline surfactant

3 Treatment

4 Geotextiles manufacture

5 Treated geotextiles

6 ParametersUntreated Fiber level Fabric level Standard Area density (g/m 2 ) ASTM D Thickness (m m) ASTM D Yarn linear density (ktex) 0.68(a), 0.99(b) 0.46(a ), 0.46(b) 0.68(a), 0.99(b) ASTM D Fabric mesh (threads/mm) 5.5(a), 3.9(b) 7.1(a), 3.9(b) 5.5(a), 3.9(b) BIS Weave pattern 1 up 1 down 1 up 2 down 1 up 1 down --- AOS 95 (  m) ASTM D Permittivity (cm/sec) ASTM D (a) Machine direction, (b) cross machine direction Geotextiles specifications

7 Sample Tensile strength (kN/m) ± CL Elongation at break (kN/m) ± CL MDCDMDCD Untreated22±621±511±108±2 Fiber level19±221±312±509±3 Fabric level25±423±313±409±2 MD: machine direction, CD: cross machine direction, CL: 95%confidence limit, narrow width tensile strength and elongation at break were measured as per ASTM D-751, 2006 Mechanical properties: Geotextiles

8 SampleWater absorption (% by wt.) ± CL Initial120-d chemical exposure 120-d physical exposure 200-d biological exposure Untreated270±35380±52310±71387±58 Fiber level 90±22110±20120±21109±13 Fabric level 120±30140±34124±35136±22 Water absorption was estimated as per Alvarez et al., 2006 Short and long term water absorption of geotextiles

9 Durability: Geotextiles Soil burial (IS: 1623, 1992): Soil burial test: 31° C, 90 % rel. hum., soil : fiber :: 100 : 1 (w:w), soil water cont. 30% Regular changes of soil compost to supply fresh nutrient Saline exposure: Periodic exposure to 30 ppt NaCl saline solution Physical weathering, AAW (ASTM D-4355:07): 500 h exposure to UV light and cyclic water spray pH exposure: Dipping of samples to the solution with pH ranges from 3 to 10 for prolonged days

10 Durability: Geotex…

11 Durability in pH exposure: Geotex…

12 Effect of biodegradation in soil burial

13 Effect of physical weathering

14 Service life estimation: From AAW From AAW results the service lives for geotextiles were estimated Data from AAW were fitted with the equation Y= A x exp(bt), where Y is the narrow strip tensile strength at time t, A, b are constant. Half life was estimated by calculating time of exposure to reach the 50% strength of initial strength by best-fit relationship (Koerner et al., 2005) Total AAW UV irradiation was scaled with total yearly UV irradiation in Kolkata (Wypych, 2003)

Service life estimation: From biodegradation… Laboratory based compost environment is more severe than typical outdoor environment Untreated geotextile degrades within 90 days in laboratory while in outer environment it lasts for months Laboratory results were scaled up with factor of 8 with outer environmental results Hence laboratory based half life was scaled up by 8 times to simulate environmental half life

Treatment Half life in AAWHalf life in soil burial Laboratory (h), r 2 Field (months) Laboratory (days), r 2 Field (months) Raw357, , Fiber level 1613, , Fabric level 1226, , Life expectancy of geotextiles

Industrial trial

Field trials

Summary and Conclusions A non-hazardous, non-expensive chemical treatment process has been developed for enhancing hydrophobicity, tensile strength and resistance to biological, chemical and physical degradation of jute An alkaline solvent free emulsion of neem oil and mostly plant based phenolic resin were used for fiber treatment Vegetable oil was found to transesterify the cellulose chain of jute

Summary and Conclusions… After degradation study long term tensile strength retention for treated fabrics was found remarkably higher than that of untreated fabric Developed treatment process was applied to manufacture industrial textile such as jute geotextile within an industrial set up of a jute mill The feasibility of proposed treatment process was found satisfactory The process was found to enhance service life of treated geotextiles upto 3-4 times compared to untreated geotextiles without compromising strength, porometry and flexibility of the textiles

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