Preparation And Properties Of Superabsorbent Resin With High Salt-resisting And Moisture-tolerating Properties

Superabsorbent resin?SAR?is a kind of three-dimensional polymeric network,which possesses extraordinary properties of water absorbency and water retention.SAR can retain the absorbed fluid for long periods even under certain pressure.Because of superior properties compared to ordinary absorbing materials?cotton,sponge and pulp?,SAR has many applications in many fields including food industry,wastewater treatment,agriculture,drug-delivery systems,hygienic products,horticulture and so on.Most of SARs are synthesized by acrylic acid,its salts and acrylamide.Vinyl monomers based SARs are costly and show unsatisfactory property in salt-containing environment and humid environment,which restrict applications of SAR in manufacture,storage and transport.The experiments grafted different materials,such as sodium humate?SH?,chitosan?CTS?,poly?vinyl alcohol??PVA?and diatomite?DT?,to vinyl monomers to achieve products.SH is an organic material,which widely distributed in nature and contains a large number of functional groups.Meanwhile,SH has capacities of adsorption,exchange,complexation and chelation.Because of biocompatibility and special groups,natural polymer?CTS?has been widely employed in many fields.Synthesized polymer?PVA?was widely used resulting from its physical properties,chemistry resistance and biodegradability.Diatomite attracts considerable attention because it has porous structure,low density and high surface area.This paper wants to provide theoretical guidance for moisture-resisting and salt-tolerating capacity by comparing different types of SAR.In this paper,acrylic acid?AA?and 2-acrylamido-2-methylpropane sulfonic acid?AMPS?was used as monomers,which blended with SH,PVA,CTS and DT to form three different types of SRAs:single network?SH/AA/AMPS?,interpenetrating network?PVA/CTS/P?AA-AMPS??andorganic-inorganicnetwork?PVA/DT/P?AA-AMPS??.The main contents are as follows:?1?Preparation and properties of superabsorbent resin of SH/AA/AMPS:the superabsorbent resin?SAR?containing sodium humate?SH?has been synthesized by free-radical graft copolymerization with acrylic acid,2-acrylamido-2-methylpropane sulfonic acid and sodium humate as monomers in aqueous solution,using N,N'-methylenebisacrylamide as crosslinker and potassium persulfate as initiator.The optimum condition shows that when the content of initiator,crosslinker and sodium humate was 1.3%,0.7%and 0.9%,the neutralization degree was 60%,the temperature was 70?,the absorbency of SAR was up to 1380g/g in distilled water and 117g/g in 0.9wt%NaCl solution.Compared with SAR without SH,moisture of SH based SAR decreases 8wt%and also has better water absorbency in different cation solutions(Na⁺,Ca²⁺,Fe³⁺).?2?Preparationandpropertiesofsuperabsorbentresinof PVA/CTS/P?AA-AMPS?:the IPN superabsorbent resin was synthesized by aqueous solutionpolymerizationmethod,usingacrylicacid?AA?and2-acrylamido-2-methylpropane sulfonic acid as monomers,poly?vinyl alcohol??PVA?assynthesizedpolymer,chitosan?CTS?asnaturalpolymer,N,N'-methylenebisacrylamide as crosslinker and potassium persulfate as initiator.The optimum condition shows that when the content of initiator,crosslinker,poly?vinyl alcohol?and chitosan was 1.3%,1%,0.6%and 0.9%,the temperature was 70?.Under optimum condition,the absorbency of the superabsorbent resin was up to 1800g/g in distilled water and 110g/g in 0.9wt%NaCl solution.The moisture absorption of IPN-SAR is lower?nearly 10-30 times?than that of single network SAR and IPN-SAR has superior absorbency capacity in various saline solutions with different cations(Na⁺,Ca²⁺,Fe³⁺).?3?Preparation and properties of PVA/DT/P?AA-AMPS?:Organic-inorganic superabsorbent resin was synthesized by aqueous solution polymerization method,using acrylic acid?AA?,2-acrylamido-2-methylpropane sulfonic acid and poly?vinyl alcohol??PVA?as organic materials,diatomite?DT?as inorganic material,N,N'-methylenebisacrylamide as crosslinker and potassium persulfate as initiator.The optimum condition shows that when the content of initiator,crosslinker,AMPS and diatomite was 1.2%,1%,25%and 0.6%,the temperature was 70?,Under optimum condition,the absorbency of the superabsorbent resin was up to 1574g/g in distilled water and 101g/g in 0.9wt%NaCl solution.The moisture absorption of organic-inorganic SAR is lower?nearly 30-40 times?than that of organic SAR and organic-inorganic SAR has superior absorbency capacity in various saline solutions with different cations(Na⁺,Ca²⁺,Fe³⁺).