Preparation And Properties Study On Super Absorbent PVA Fiber

Super water-absorbent fiber (SAP) is a kind of functional fiber, which develops on the base of super water-absorbent polymer (SAP). SAF has good performance of water-absorption capacity and water-retention capacity. It has good strength and can maintain the fiber integrity after absorbing water. It is easy to process, so SAF has a great application prospect. At present, only several developed countries are able to produce SAF, while in China SAF is at the initial stage.This paper is about the preparation of SAF, using low-temperature water-soluble PVA fiber as raw material and maleic anhydride as cross-linking agent. The experiment is to make a chemical cross-linking reaction to PVA fiber to form a cross-linked network structure and then to test the various properties of the super absorbent PVA fiber. The main contents are as follows:Study the influence that reaction conditions of chemical cross-linking have on water absorbency of super absorbent PVA fiber. And the reaction conditions include cross-linking temperature, cross-linking time and the amount of maleic anhydride. The results show that the water absorbency will increase at the beginning and then decrease, with the increased use of amount of maleic anhydride, as well as the impact of the cross-linking temperature and cross-linking time. Super absorbent PVA fiber that has an appropriate cross-linking degree can be prepared under the condition: the amount of maleic anhydride is 5:100～25:100, cross-linking temperature is 75℃～90℃and cross-linking time is 1～5hours. When the amount of maleic anhydride is 20:100, cross-linking temperature is 85℃and cross-linking time is 3hours, the water absorbency can be up to 135 times.Study the influence that alkali treatment conditions have on water-absorption rate of super absorbent PVA fiber. The results show that alkali treatment can increase the water-absorption rate effectively. The reasonable alkali treatment conditions are as follows: NaOH concentration of 3%, alkali processing time is 4min. The water-absorption rate is high and the fiber need only 4～6s to reach the half amount of saturated absorbent, much higher than SAP.Characterize the molecules structure and surface morphology of super absorbent PVA fiber using IR method and scanning electron microscopy (SEM). IR spectra shows that the chemical groups on the PVA macromolecular have changed because maleic anhydride graft to the PVA molecules. As a result, cross-linking network structure has formed between PVA macromolecular. The SEM photographs about the vertical surface of super absorbent PVA fiber show that there is a lot of grooves and cracks on the fiber surface, which help improve the water absorption rate and water absorbency.Study the mechanical properties of super absorbent PVA fiber. Test results show that the strength of super absorbent PVA fiber is enough for non-woven processing and is suitable for processing of absorbent non-woven materials.In a word, low-temperature water-soluble PVA fiber can change into super absorbent PVA fiber by chemical cross-linking method. The super absorbent PVA fiber which is prepared meets the performance requirements of SAF and is suitable for non-woven processing, so as to carry on further studies of non-woven processing.