P. K. Ray

37—THE PROPERTIES OF JUTE FIBRES AT DIFFERENT STAGES OF PLANT GROWTH

An investigation is described in which cell-wall thickness, linear density, and filament tenacity were studied for jute fibres of both the C. capsularis and C. olitorius species at different stages of growth of the jute plant. It is shown that the cell-wall thickness goes on increasing for 120 days and then levels off, whereas the linear density goes on increasing for only about 60 days and then falls and levels off after 80 days. The fact that, despite the increase in cell-wall thickness, the linear density does not increase afier 70–80 days indicates that filaments become split at some stage prior to ihe determination of linear density. Breaking strength at first increases rapidly and then levels off after 80 days and falls after 120 days. Variation in breaking strengih is consistent with the variation in multicellular character, cementing material, and fine structure of the fibre with the growth of the plant.

31—THE EFFECT OF THE APPLICATION OF BATCHING OIL ON THE FINE STRUCTURE AND MECHANICAL PROPERTIES OF JUTE

An investigation is described in which jute filaments obtained from breaker-card sliver were subjected to the following treatments: (i) samples were made moisture-free but retained the batching oil; (ii) samples were made both moisture-free and oil-free; (iii) moisture-free and oil-free samples were soaked in water and again made moisture-free. Jute filaments were also obtained from raw fibre and from raw fibre from which natural fat and wax had been removed. The X-ray crystallinity was determined for all the samples in the moisture-free condition. The results obtained are explained on the basis of a paracrystalline structure of cellulosic fibre, some regions of which are capable of diffracting X-rays and at the same time are accessible to moisture. It has been proposed that, when the fibre is treated with an oil–water emulsion, water molecules penetrate into the amorphous regions and into portions of the region of intermediate order (paracrystalline), the resultant swelling then producing fissures that o...