Research On Synthesis Of Polyaspartate And Interpenetrating Polymer Network Superabsorbent

Polyaspartic acid(PAsp)is a kind of biodegradable superabsorbent polymer,which has a large number of hydrophilic groups.However,the practical application of pure PAsp is limited because of its simplex in properties,such as poor salt resistance and gel intensity.And there are lots of defects in synthesis process of PAsp superabsorbent polymer,such as the difficulty of product reprocessing,the toxicity of the diamines.Therefore,this paper was to add the modification(3-aminopropyl)triethoxysilane(KH550)in the preparation of PAsp superabsorbent polymer,resulting in the traditional synthesis process was improved and the product was obtained in water.This method overcame the difficulty of product reprocessing and avoided using the toxic diamine.And the salt resistance of product was improved because of introducing the silicon groups.On the basis of the study,the interpenetrating polymer network was introduced in order to improve the salt resistance and water-retaining property of KPAsp and broaden the range of application.In this paper,polyaspartic acid superabsorbent(KPAsp)was produced using polysuccinimide(PSI)as the raw materials and KH550 as the modification agent by hydrolysis and crosslinking.And the effect of the preparation factors on the water absorbent was investigated.The results showed that the polyaspartic acid superabsorbent can be modified by KH550 and the effects of some reaction conditions on the absorbent properties were significant,such as the content of modification agent,the pH of hydrolysis,the crosslinking time and temperature.The maxium swelling ratio was 455g/g in distilled water and 115g/g in 0.9%NaCl solution on the optimized conditions as follows:1.2mol%of KH550(based on PSI),the use ratio of PSI and DMF was lg/lOml,50 ℃ of graft reaction temperature,3h of graft reaction time,20wt%of the hydrolysis concentration,4h of hydrolysis reaction time,10 of hydrolysis pH,75 ℃ of crosslinking reaction temperature,2h of crosslinking reaction time.It is found that the product exhibited quite good water-retentaining property and remarkable sensitivity to salt solutions,tempreture and pH.The structure and morphology of product were characterized by scanning electron microscope(SEM).On the basis of the above mentioned work,a novel super absorbent polymer of KPAsp/PAA interpenetrating polymer network was synthesised by synchronization method,using hydrolyzed PASP and partly neutralized acrylic acid(AA)as raw material,potassium peroxydisulfate as initiator,N,N-methylene double acrylamide as cross linking agents.Effects of synthetic parameters on the absorbing properties of KPAsp/PAA IPNSAP were studied.When the mass ratio of AAc(Na)to PASP was 1:1,the content of initiator was 0.5wt%,the content of crosslinking agent was 0.4wt%,the neutralization degree of AA was 80%,the reaction temperature was 75℃ and the reaction time was 2h,the swelling ratio of KPAsp/PAA IPNSAP couled reach 1034 g/g and 192 g/g in distilled water and 0.9%NaCl solution,respectively.Compared with KPAsp,the swelling ratio of KPAsp/PAA IPNSAP was improved of127.3%and 67.0%.And it is found that the KPAsp/PAA IPNSAP exhibit quite good water-retentaining property and salt resistance.