Study On Preparation And Properties Of Sodium Alginate Superabsorbent Polymer

As an abundant ocean resource, algae has the characteristic of strong revegetate and biodegradable ability. It is expected that it could be used as a new resin in material field. Sodium alginate resins are used commercially in the form of ionic gels crosslinked with mutivalet metal cation. However, Sodium alginate resins show low water absorbencies and poor mechanical property due to their own properties and high crosslink desity of the gels. In this dissertation, sodium alginate is etherificated in order to meliorate its compatible performance and chemical stability. By polymer molecular design, a series of complex superabsorbent resins based on etherificated sodium algiate (ESA) are prepared. The effects of various factors including monomer types, monomer concentration, solution media and crosslink temperature on water absorbency and mechanical strength of resins are studied. The surface configuration, thermal stability, degradation behavior, swelling stability and moisture retention properties in soil are also studied. The research proposes a new technical approach for the application of ESA superabsorbent in material field.The result of the experiments shows that viscosity is degraded and chemical stability is enhanced for sodium alginate by etherificate, and the best etherificate degree (Ds) is within 0.2-0.5 while the optimized ESA content is within 20%. Under the optimized reaction condition, Grafting ratio is high and ESA/AA and ESA/AA/AM resins have higher water and saline absorbency.Polymer network with different compositions is synthesized, characterization result with IR, DSC and SEM proves that there are physical intertwises and chemical bonds among molecule chains on polymer surfaces. SEM analysis indicates that with the composition ratio, m(ESA/AA):m(PVA)=88 : 12 , m(ESA/AA): mP (AM) =92: 8 and w (PVA+P (AM)) =10%, m (PVA): m[P (AM) ]= 70:30, the ESA/AA/PVA, ESA/AA/P(AM), ESA/AA/PVA/P(AM) resins...