Dr. N.N. MAHAPATRA
Business Head(Dyes)
Shree Pushkar Chemicals & Fertilisers Ltd.
Long fibres are derived from the stems of the mallow plant Urena lobata, which is indigenous to Brazil. Known as Aramina fibres, they are utilised for producing cords, twine, and burlap fabrics. This plant, classified as a noxious weed in the U.S. since 1999, belongs to the Malvaceae family and is a perennial grass commonly found in tropical and subtropical regions such as Brazil, India, Madagascar, and Africa. The fibres are harvested when the plant is in full bloom, characterised by pink flowers, and are noted for their creamy white colour, lustre, softness, and flexibility—qualities that make them comparable to jute.
In Kenya, where most vegetable fibres are imported except for cotton and sisal, there is a pressing need for research into alternative vegetable fibre sources. This study specifically focuses on assessing the quality of Aramina fibres from Urena lobata, which proliferates as a weed in the region.
Production of Aramina Fibers
The extraction of Urena lobata fibres is achieved through natural water retting. This process involves stripping the bark from the woody portion of the plant and subjecting it to partial retting by immersion in water for approximately two weeks. From 22 kg of unretted green bark, about 2.6 kg of fibres can be extracted. It is important to note that unretted bark contains impurities and moisture, making it significantly heavier than dry fibres.
Properties of Aramina Fibers
Urena lobata can grow between 3 to 7 feet in its wild state but can reach heights of up to 13 feet when cultivated. The fibre strands exhibit a cream colour and possess an appealing lustre. While primarily cultivated in the Congo region, smaller quantities are also produced in Brazil, India, and the Philippines. The fibre has a staple length of 13.5 cm and shares burning characteristics with other natural cellulose fibres like cotton and linen.
The moisture regain value of Aramina fibres is recorded at 9.7%, with wet fibres being 42.9% stronger than their dry counterparts. The elongation percentage is noted at 1.035 when dry and increases to 1.3% when wet. The moisture content significantly influences both elongation and fibre strength (tenacity), which measures 2.0 g/d for wet fibres compared to 1.4 g/d for dry ones—similar to jute.
Chemically, Aramina fibres are sensitive to acids; thus, they cannot be dyed with acidic dyestuffs or stored in acidic solvents. This characteristic plays a crucial role in forming oxycellulose for regenerated fibre manufacturing. The resilience and pliability of these fibres enable them to be spun into yarns that can be dyed and transformed into various products.
Applications of Aramina Fibers
Aramina fibres find applications in making cords, twine, and burlap fabrics, with ongoing evaluations for their potential use in pulp and paper production. They can also be utilised in coarse textiles.
Various crafting techniques such as crocheting, plaiting, hand weaving, card weaving, and macramé knots can be employed to create items including shoulder bags, table mats, floor mats, belts, plant hangers, and toothpick holder covers. Given its local availability in Kenya at an economical price with good spinning and dyeing qualities, Aramina fibre is recommended for both large-scale and small-scale textile industry usage.
Additionally, these fibres can serve as composite reinforcements. Natural fibre reinforcements have gained attention due to their biodegradability, cost-effectiveness, CO2 neutrality, ready availability, non-abrasiveness, low weight, renewability, and favourable mechanical properties compared to synthetic alternatives. However, challenges such as hydrophilicity, reduced interfacial bonding, and diminished thermal strength may limit their application in composites reinforced with natural fibres.
