Gel Permeation Characteristics of Jute and Cotton

Abstract

Gel permeation chromatography measurements, which have been used to demonstrate changes in the pore structure of cotton resulting from chemical modification, were used to compare the pore structures of jute and purified cotton cellulose and to determine the effect of scouring on jute. Both native and scoured jute had greater pore volumes than purified cotton. Scouring effected an increase in the internal volume of the jute fiber over the measured range of pore sizes. Data on the fraction of the total internal water volume accessible to the water molecule itself indicated a similarity between cotton and scoured jute, but these and other data suggested a repelling interaction between the surfaces on the internal pores of native jute and the sugars used as test solutes. This repellant effect is attributed to the presence of lignin on these surfaces.Previous reports discussed using the gel permeation technique to measure pore structure and changes in pore structure produced by chemical modification of cotton cellulose [2, [5][6][7][8][9]. Chopped or ball-milled samples of the cellulosic substrate were used as the packing in chromatographic columns. The elution volumes of . selected solutes having a range of known, discrete molecular weights were measured to characterize pore structure. Our study extends this type of investigation to jute, a lignocellulosic bast fiber. The pore structure of jute is compared with that of purified cotton cellulose, and the effect of scouring on the pore structure of jute is elucidated. Experimental . MATERIALSThe jute (Corchorus capsularis) was grown in Kaliakair, Bangladesh, 20 miles north of Dhaka. The seeds were planted in the spring of 1981 and the jute harvested in early fall. The plants were retted in flowing river water (--35°C) for approximately two weeks, the fibers stripped from the stems, and then sun dried for 2-5 hours. The fibers had been in storage approximately 9 months at the time of testing.-The cotton was ACCO Absorbent Cotton U.S.P. 96-9117 from Absorbent Cotton Co., Division of Dart Industries.3Dextran T-40 (MW = 40,000) was from Pharmacia; glucose was from Mallinkrodt Chemical Works; maltose and rafhnose were from Calbiochem; stachyose was from Aldrich Chemical Corp.The water used to elute solutes through the chromatographic columns was deionized and then further purified by passage through a Water-I system from Gelman Sciences. It was degassed by sonication under reduced pressure for 20 minutes. METHODS -Jute was examined in both the native and scoured state. It was cut into 1 inch lengths and cleaned mechanically in an experimental carding cleaner designed for removing debris from wool. Part of this mechanically cleaned jute was purified by scouring. The jute was placed in a 4 liter stainless steel beaker and covered with 4 liters of the scouring solution which contained 2% NADH and 0.5% Prechem 70 (weight/weight). The mixture was brought to a boil and held there for 30 minutes. The scouring solution was then replaced with fresh scouring solution and the procedur...