Methods For Measuring Performances Of Starch Grafted Super Absorption Polymer And Residual Monomer Enrichment

Super absorbent polymer (SAP) is a new type of material. It applies in many places for the water absorption reaching to several hundreds even to thousands. But the methods of performances have not been unified. Experiment errors are brought by the different methods. In this paper, measurements for the performances of SAP and the enrichment process of acrylic acid and acrylamide were explored. Operating procedures were generalized.It can be concluded that water absorption of SAP can be determined more accurate by the filtration method by a lot of experiments. The suggested measurement for water absorption of SAP is concluded, 0.10-0.12 mm grain of SAP, dipped in distilled water which weight is more than 1200 times to the weigh of SAP for 40min with a 100 mess sieve, the filtration time is 60min.The method for measuring the liquid absorption speed (LAS) of SAP was investigated. The filtration method with 100 mesh sieve was used to measure the absorption time dependence of water-absorbency, then the LAS was derived. The suggested conditions for the measurement are distilled water as liquid media and 0.10-0.12mm grain of resin as absorption agent with the ratio of water/resin (w/w) higher than 1200:1 at 25℃, the average absorption speed in 16 min determined is a good index for the liquid absorption speed of SAP.A simple apparatus was made to determine water-retention rate of the SAP gel. The suggested conditions for the measurement are 120 times weight to the gel, the press time is 20min. The water-retention rate at 45℃for 8 h can represent the dehydration of SAP gel in normal condition.A apparatus was designed to measure transmutation of gel of the SAP. The feasible condition to measure the transmutation of gel of SAP is the gel being pressed by a weight which is 120 times to the gel for 30 min.Acrylic acid and acrylamide were enriched from SAP by a Soxhiet extraction. The feasible condition are 5-8g of sample, the recycling time was 20 min one time with 70% methyl alcohol and distilled more than 10h.