Preparation And Properties Of Electrospun Water-absorbing Fibers

Water-absorbing fiber is a new functional fiber that developed from water-absorbing polymer.It has good water absorption capacity,water absorption rate and water-holding capacity due to its unique structure which is three-dimensional cross-linked network and numerous hydrophilic groups on the macromolecular chain.Water-absorbing fiber has been widely used in medical and hygienic materials,filtration and separation materials,and industry,agriculture,forestry and so on.In this paper,the polyacrylic acid absorbent fiber was prepared and the properties were analyzed.The poly(acrylic acid-acrylamide)/polyvinyl alcohol solution was prepared when the polyvinyl alcohol(PVA)solution was added to copolymer of acrylic acid(AA)and acrylamide(AM).And then,the poly(acrylic acid-acrylamide)/polyvinyl alcohol solution was electrospun to get water-absorbing fibers with micro/nano structure,and the hygroscopicity,water-absorbing performance and water retention of fibers were studied.The preparation of water-absorbing fibers was studied and the effects of spinning voltage,nozzle diameter and receiving distance on the fiber morphologies and fiber diameters were analyzed.The results show that the micro-nanofibers have better morphologies when the polymer solution is at a voltage of 15-18 kV,the nozzle diameter is in 0.25-0.70 mm,the solidification distance is in 18-22 cm,and the spinning advancing speed is in 5-15 ul/min.Through theorthogonal experimental analysis,it was found that when the spinning voltage was 17 kV,the curing distance was 20 cm,and the diameter of nozzle was 0.25 mm,the water-absorbing fiber with the smallest average diameter can be obtained.The structures and water absorbability of water-absorbing fibers were studied.The results of infrared spectroscopy show that there are ether bonds than can indicate the cross-linking of fiber is chemical cross-linking;the fiber has good water absorption capacity because of a large number of hydrophilic groups.The thermogravimetric analysis of electrospun water-absorbing fibers could further verify the structure of fibers,the spectrogram mainly included four mass loss zones,which were free water,polyvinyl alcohol,polyacrylic acid,and polyacrylamide.Under the environment of air relative humidity was 65%(20 °C),the effective time of moisture absorption of the electrospun water-absorbing fibers lasted about 50 minutes,and then fibers could continue to absorb;the viscose fiber's effective water absorption time was obviously much smaller,which was only about 15 minutes.The water absorption capacity of water-absorbing fibers was from 50 g/g to 265 g/g under different fiber diameters,different thermo-crosslink temperatures,and thermo-crosslink times.When the fiber was treated at 130 °C for 10 min,its water absorption ratio reached the highest value which was 262 g/g.The water retention performance test showed that,after drying at 35 °C and 60 °C for 2 hours,the rate of water retention separately were 64.5% and 47%.