Study On Preparation And Properties Of Electrospun Fibers Film From Naturally Colored Cotton

In this paper nanofibers or submicron fibers have been successfully prepared through elelctrospining naturally colored cotton cellulose solution, after hot alkali treatment and being solved in lithium chloride (LiCl)/N,N-dimethyl acetamide(DMAc); absorbtion property of electrspun fibers film to copper ion also have been elevated by chloroactic acid etherification at the surface. And it was discussed in more detail that cellulose LiCl/DMAc solution of naturally colored cotton fibers was chosen for electrospining , technics parameters affected electrospun fibers appearance, diameter and physics properties, and their film adsorped copper ion.Cellulose solution of naturally colored cotton fiber was non-newtonian in LiCl/DMAc,and fluidity property of cellulose solutions were very low with concentration above the 1.2% . Cellulose solution fluidity property of brown cotton fiber was the same as that of green cotton fiber, but non-newtonian index of the former was higher than that of latter., and thus it was difficult to be electrospun. Along with temperature increasing or cellulose concentration decreasing, fluidity property of their cellulose solutions went better and non-newtonian index increased. In addition, solution apparent viscosity firstly increased and then decreased obviously. At last, brown cotton fiber was chosen to be electrospun at 25-35℃temperature and the concentration below 1.2% after 1h treatment of hot ailkali, and submicron fibers was obtained with the average diameter of 96.9861nm and the Standard Deviation of 23.2210.LiCl/DMAc of high boiling point made electrospun fibers fuse and bundle tegother during the course of cellulose solution LiCl/DMAc of naturally colored cotton fiber electrospining, by which jet division theory was proved. High humidity which benefited the decreasing of electrospun fiber fusing and bundling, could be obtained through pasting wet dustproof cloth to surface of fiber-collecting roller. Also fibers fusing and bundling could decreased after they immerging in -15℃methanol/water coagulation, which washed out LiCl and DMAc inside the electrospun fibers, as well as fibers diameter decreasing 300-500nm. It was observed that corona discharge occurred easily as well as electric charge leaking, which was detrimental to jet formation, pulling and division During the electrospinning of brown cotton cellulose solution in LiCl/DMAc, low concentration, high flow rate and temperature were beneficial to jet formation, pulling and division. And its solution elelctrosping could not be insured only by elevating flow rate when its fluidity was very low, but realized through elevating temperature. In addition, solution jet could not be divided when flow rate is very high. X-ray diffraction pattern of cellulose electrospun fibers from brown coton with Type-II crystalline peaks of at 12.1903·, 20.1058·and 21.898·was shown, and it was of the crystalline degree of 11.232%, which decreased along with flow rate increasing. In addition, mechanics property of brown cotton cellulose electrospun fibers was different from one direction to another. Broken elongation intensity decreased at the direction parallel to roller rotation direction along with flow rate increasing, but increased at the its vertical direction. Therefore brown cotton cellulose electrospun fibers were arranged in the direction parallel to roller rotation direction.It was noted that brown cotton cellulose electrospun fibers contained about 300mmg/g after 4 h chloroactic acid etherification through chemical charactering and analyzing. And IR spectra showed that carboxyl, conjugate carbonyl and hydroxyl groups were related with adsorption of brown cotton electrospun fibers film to copper ion, which were etherified with chloroactic acid. And along with pH increasing its adsorption increased rapidly at the range of 1-4, but very slowly at the range of 4-7. Therefore it was indicated adsorption for copper ion mainly was concerned with carboxyl ion at the chloroactic acid etherified electrospun fibers film of brown cotton. Through assuring models of brown cotton cellulose electrospun fibers film absorption kinetics for copper ion and isothermal line, it was indicated that Lagergren second order equation was superior, which proved that absorption for copper ion belonged to chemical absorption in agreement with the chemical bond between carboxyl ion and copper ion, and that Langmuir isothermal line was superior to Freundlich, which proved that adsorption for copper ion was the single molecular layer of saturation and uniformity.