Graft copolymerization of nitrile monomers onto bleached jute fiber using potassium persulfate system and their textile characteristics

Abstract

Graft copolymerization of nitrile monomers, such as acrylonitrile and methacrylonitrile, onto bleached jute fiber was carried out by using K 2 S 2 O 8 /FeSO 4 redox system in nitrogen atmosphere and their effect on the textile characteristics was also investigated. Percent graft yield increased with the increase of concentrations of monomer, initiator, and catalyst, reaction time, and reaction temperature up to a certain value, and, thereafter, it decreased. The effect of percent grafting efficiency was similar to that of percent graft yield, except for the monomer concentration. The increase of percent graft yield was dependent on the availability of jute-macroradicals as well as monomer radicals. Sometimes the predominancy of homopolymerization over grafting and the premature termination of growing grafted chains occurred because of the higher monomer radicals and excess primary radicals, SO 4 Ϫ• and • OH, from K 2 S 2 O 8 initiator. The percent graft yield of acrylonitrile and methacrylonitrile was 20.5 and 29.1%, respectively. Higher graft yield for methacrylonitrile might be due to the methyl group present in it. Infrared spectra at 2229 -2235 cm Ϫ1 of acrylonitrile-and methacrylonitrile-grafted jute strongly supported the graft formation. Grafting of jute fiber improved the thermal stability, protected from photooxidative degradation, and decreased swellability as well as dyeability, etc.

Characterization of grafted jute fiber using acrylate monomers pretreated with alkali

“…Dirt and waste materials were removed by treating the fiber with 6.5 g of detergent and 3.5 g of soda per liter at 70-75 °C for 30 min (Farouqui and Mondal 1989). This raw jute fiber was bleached with a 5 g/L sodium chlorite solution of pH 4 at 85-90 °C, for 90 min, in a fiber-liquor ratio of 1:50 (Mondal et al , 2004. After being washed well with distilled water, this fiber was rinsed with a 0.2 % sodium metabisulfite solution for 15 min.…”

“…One twist per 2 cm was given, along with the length of the fiber between the jaws, for measuring tensile strength. In each experiment, breaking strength for 10 specimens was taken and the mean of 10 readings was assumed to represent the tensile strength of the fiber (Mondal 2004). Breaking load was calculated as kg/yarn.…”

“…Decrease in graft yield beyond the optimum temperature might be the result of homopolymer formation over grafting. It is also possible that the growing grafted chains were prematurely terminated by the excess Fe(III) ions produced by the oxidation of the Fe(II) ions (Mondal et al , 2004. At temperatures over 60 °C, for both the EA and HEMA, the reaction became reversible.…”

“…This grafting has been done using chemical Mondal et al 2004Mondal et al , 2006Mondal 2003;Mondal and Haque 2007), photochemical (Ghosh and Paul 1983) and radiation-induced (Khan et al 2010(Khan et al , 2015Zaman et al 2012) methods. In these attempts, the grafted fiber has shown improved thermal, tensile and color fastness properties.…”

“…Other work has been done on graft copolymerization of jute fiber with nitrile (Mondal et al , 2004Mondal 2003), acrylate (Mondal and Haque 2007;Mondal et al 2006Mondal et al , 2013, acrylic and amide monomer (Mondal et al 2002) monomers. The purpose was to develop the grafting process and improve the resultant physical properties of the modified products.…”