Preparation And Properties Of Interpenetrating Polymer Network Super Absorbent Polymer Based On Polyaspartic Acid Series

Polyaspartic acid(PAsp)was a kind of non-toxious and biodegradable super absorbent polymer.Hower,the practical application of pure PAsp was limited because of its simplex in properties.In this paper,interpenetrating polymer network was introduced in order to improve salt resistance and water-retentaining property of PAsp.In chapter,crosslinked Polyaspartic acid was prepared using polysuccinimide(PSI)as the raw materials and hexamethylene diamine as the crosslinking agent.Then polyaspartic acid/polyacrylic acid super absorbent polymer with interpenetrating polymer network(PAsp/PAAc IPNSAP)was prepared using crosslinked Polyaspartic acid and partly neutralized acrylic acid(AAc)as raw materials,potassium peroxydisulfate as the initiator,N,N-methylene double acrylamide as the crosslinking agents,tetramethylethylenediamine as the catalyst.The effects of synthetic parameters on the absorbing properties of PAsp/PAAc IPNSAP were studied.When the mass ratio of AAc(Na)to PAsp,the content of initiator and crosslinking agent,the neutralization degree of AAc,the reaction temperature and time was kept as 1:1,0.45 wt%and 0.4wt%,75%,70 ? and 5h,respectively,the swelling ratio of PAsp/PAAc IPNSAP couled reach 826g/g in distilled water and 120 g/g in 0.9%NaCl solution.It was found that PAsp/PAAc IPNSAP could exhibit quite good water-retentaining property and remarkable sensitivity to salt solutions,tempreture and pH.The SEM charaterization of PAsp/PAAc IPNSAP revealed an structure with uniform surface,compact pores and without obvious phase separation phenomenon.In chapter,non-ionic co-monomer AM was introduced into PAsp/PAAc IPNSAP in order to synthesize PAsp/P(AAc-AM)IPNSAP with diverse hydrophilic groups,which was believed to be able to improve the water absorbency as well as the salt resistance and water-retentaining property of PAsp/PAAc IPNSAP.The effects of synthetic parameters on the absorbing properties of PAsp/P(AAc-AM)IPNSAP were studied.When the mass ratio of the monomers(AAc and AM)to PAsp and AAc to AM,the content of initiator and crosslinking agent is 1.35:1 and 6:4,0.5wt%and 0.06wt%,respectively,the swelling property of PAsp/P(AAc-AM)IPNSAP was the best.It was found that the swelling ratio of PAsp/P(AAc-AM)IPNSAP could be improved by 38.7%in distilled water and 91.7%in 0.9%NaCl solution,compared with PAsp/PAAc IPNSAP.Moreover,the water-retentaining property and the thermal stability increased significantly.The biodegradable properties of PAsp/PAAc IPNSAP and the mechanical mixture of PAsp and PAAc were also compared.After 28 days,the biodegra-dation ratio of PAsp/PAAc IPNSAP and the mechanical mixture of PAsp and PAAc was 68.4%and 50.1%,respectively,implying that the existence of interpenetrating polymer network could accelerate the biodegradation of super absorbent polymer.