Chemical Modification of Jute Fiber

jute fiber

Jute is a natural biodegradable fiber with advantages such as high tensile strength, excellent thermal conductivity, coolness, ventilation function et al.1-2. Recently, due to the improvement of people’s living standards and need for environmental protection, the demand of natural biodegradable and eco-friendly fibers is rising worldwide day by day. Ramie, flax, hemp and some other vegetable fibers have been used as textile materials, but jute fiber is basically used for traditional purposes such as manufacture of sackings, hessian, carpet backing and the like. Taking account of the costliness of ramie and the shortage in sources of flax, and the challenges from the synthetic fibers in the traditional jute products market, if jute could be used to replace ramie and flax partially as textile material, not only the cost could be reduced but also a new market would be provided for jute products.

Jute fiber is a bast fiber obtained from the bark of jute plant containing three main categories of chemical compounds namely cellulose (58~63%), hemicellulose (20~24%) and lignin (12~15%), and some other small quantities of constituents like fats, pectin, aqueous extract, et al. Jute fiber is composed of small units of cellulose surrounded and cemented together by lignin and hemi-cellulose10-11. The low cellulose content, coarseness, stiffness, low extensibility, low grip performance and some other disadvantages seriously restrict the raw jute fiber from spinning. So a series of wet chemical processing sequences are needed to improve the spinnability of jute. The qualities of the fiber and yarn mostly depend on the degumming effect. So degumming is one of the most important sequences in the chemical processing of jute.

Generally, there are three methods for degumming, i.e., mechanical, chemical and biological methods. The mechanical methods such as steam explosion2,14, microwave and ultrasonic 15 have very limited effect on improving the spinnability of jute fiber. Biodegumming is an eco-friendly method has some advantages viz. mild conditions and high efficiency. However, the application of enzymes for degumming is hindered by some factors such as high substrate specificity, low activity stability, high cost, and low total gum decomposition16-18. The chemical method is the most commonly used method for degumming, but this traditional method has some major disadvantages like serious environmental pollution, lengthy time required and high cost 19. Taking account of these problems, it is urgent to improve the degumming method for natural fibers.

In our previous study, the pre-chlorite treatment of jute fiber before degumming has been reported to lighten the burden of degumming and enhance delignification20. In this paper, we report the chemical degumming of the pre-chlorite treated jute fiber. Both the gum decomposition and the spinnabilities viz. fineness, breaking strength and breaking extension were tested to optimize the conditions for degumming. Changes in the constituent content of the treated jute fiber were also analyzed.

Materials and Method:
Materials
Jute:
Lightly combed and dewaxed raw jute fiber.

Chemicals:
Sodium chlorite and sodium silicate, Acetic acid, sodium acetate, sodium hydroxide and sulphuric acid , Penetrating agent TF-107B and degumming agent TF-125A .

Methods
Pre-chlorite treatment
The samples were treated in a bath with sodium chlorite 1.5g/L, pH 3, liquor ratio 1:10, and kept at 30℃ for 30 min. and then thoroughly washed.

Scouring
The pre-chlorite treated jute fiber was treated with sodium hydroxide 5-30g/L, sodium silicate 1.0-5.0g/L, TF-107B 0.5-6.0g/L, TF-125A 1.0-8.0g/L, and kept at 60-100℃ for 60-240 min. with fiber to liquor ratio 1:10-1:40. At the end of the desired treatment, the fibers were neutralized with sulphuric acid, and then thoroughly washed with distilled water.

Testing
Breaking strength and breaking extension were tested using a XQ-1 fiber breaking strength machine in a constant 20℃ temperature and 65% relative humidity room (in accordance with ASTM Method D-5035). The fineness was tested according to GB/T12411.3. The constituent contents were tested according to GB/5889–86.