Synthesis Of Super Absorbent Resin Of Starch/AA/AM/MA By Inverse Suspension Polymerization

Cassava starch grafted Super absorbent resin is a kind of new functional polymer materials, which are widely used in various fields such as petroleum industry, agriculture, medicine and hygiene. In this paper, a super-absorbent resin was synthesized by inverse suspension copolymerization and twice initiation, using industrial grade cassava starch, acrylic acid(AA), acrylamid(AM) and methyl acrylate(MA). It was systematically investigated that the effect of reaction conditions on water(or salt water) absorbency, system dispersion, recovery of solvent. The main contents and conclusions were as follows:(1) Although industrial grade acrylic acid and methyl acrylate contain inhibitor, a super-absorbent resin can be synthesized using industrial grade acrylic acid and methyl acrylate that shouldn't distillated first, cassava starch, acrylamid.(2) Adds proper hydrophobic monomer(MA) in the system that contains starch and hydrophilic monomer (AA and AM) , it was founded that the absorbing capacities of resin for water and salt-water is improved about 20%. (3) In maens of inverse suspension copolymerization, through adds dispersing agent and MA, the problems that polymer becomes gel (or adhesive) and isn't easily treated was solved. Simultaneously, polymer is coarse grained and wraps few solvent when adds MA, so the recovery of cyclohexane is improved.(4) The suitable synthetic conditions include:cyclohexane as continuous phase, T-70 as dispersing agent, the ratio solvent to water phase 1.90:1.00 (v/v) ; potassium persulfate and sodium bisulfite (their molarity were same) as initiator, concentration of initiator(twice initiation) 2.0,13.5 mmol·L^-1(only calculat one of they); N,N-mythylene bisacrylamide as cross-linking agent, dosages of cross-linking agent 0.3%(based on the total mass of AA and AM); m(starch):m(AA):m(AM)=1.0:4.5:0.9, dosages of MA 5.0% (based on the total mass of AA and AM). The reaction time 3 hours, stirring speed 360 r/min.The best absorbability of Super absorbent resin in salt free water≥600g·g^-1 and≥60g·g^-1 in 0.9% NaCl solution, that's Considerable to the product made by Sumitomo Seika.Finally, the structure of synthetic resin was identified by FT-IR. From analysis results, it was inferred that the product is copolymer of cassava starch, AA, AM, and MA.