Synthesis And Performance Study Of Polyacrylate Superabsorbent Polymer

Superabsorbent Polymer (SAP) is a kind of water swelling polymer, with theunique absorption ability and water retention capacity, which is widely used inpetroleum chemical industry, water treatment, agricultural industry, forestry andgardening, etc. At present, there are many reports about synthesis and characterizationof SAP, However, there has been no significant breakthrough about salt-resistantsuperabsorbent. The purpose of this paper is to improve the system stability,absorptive power and salt-resistance capacity, so we did a lot of research onpolymerization process. In this paper, we did three parts of research on the synthesisof superabsorbents, which are based on polyacrylate superabsorbent polymer.(1) Synthesis of PAANa PAANa was prepared by using the inverse suspensionpolymerization, with H-261as the dispersant, APS-NaHSO3as the low temperatureinitiator. For index on the stability of the reaction system and product performance,the conditions of polymerization process was studied detailly, such as neutralizationdegree of acrylic acid; initiator ratio; reaction temperature, etc. At the same time,orthogonal experiment (L1837and L93~4) were used twice to survey the processconditions widely, and then we determined the synthetic conditions of PAANa. Thepure water absorption of the product is1000g/g, the salt water (0.9%NaCl)absorption is54g/g.(2) Synthesis of salt-resistent superabsorbents (P(AA/AM)Na) In order toimprove salt-resistance, the monomer ions were added in the polymerization system,which was acrylamide (AM) or methyl methacrylate β hydroxyl ethyl (HEC). Theaddition amount of the monomer ions, the sorts of reductants were investigatedthoroughly. The pure water absorption of the product is1400g/g, the salt waterabsorption is72g/g.(3) Synthesis of salt-resistent superabsorbents (P(AA/MA)Na) P(AA/MA)Nawas prepared by using the inverse suspension polymerization, with H-261as the dispersant, APS-U as the low temperature initiator. And then, the process parameterswere studied detailly, such as neutralization degree of MA, H-261dosage, etc. Thepure water absorption of the product is2069g/g, the salt water absorption is107g/g.The structures and the heat-resistant quality of the obtained products werecharacterized by IR, SEM and TG-DTA, etc. Test results show that there are lots of–COOH in the products and double bond had completely polymerized;(P(AA/AM)Na) has the biggest particle size, but P (AA/MA)Na scattered bestly andhas the densest internal pore; three kinds of resin have a similar thermal capacity andstability is quite good within100℃.In addition, comprehensive research was done on the performance study ofSuperabsorbents, such as the water absorption ability, bibulous rate, weatherresistance, resistance to view of electrolyte performance, etc. The results show thatthese three kinds of SAP not only have great water imbibition and water retentivity,but also have good salt tolerance and weather resistance. Meanwhile, we detect theresidual monomers of samples by HPLC, test results show that the content of AA isvery low, conforming with the state standards.Secondary polymerization was used to synthesis large particle size of resin, withAA as the lord monomer, AM as comonomer, APS-rongalite as the low temperatureinitiator system. The size of resin is at4~6mm after sucking water.