Method for preparing poly(acrylic acid-acrylic amide)/hydrotalcite high water absorption resin

[0014] Example 1

[0015] First, add hydrotalcite and modifier into N,N'-dimethylacetamide, stir vigorously at 70-80°C for 22-24 hours, filter with suction, wash and dry to obtain organically modified hydrotalcite , the modifier can be sodium methacrylate, sodium propene sulfonate or sodium dodecylsulfonate.

[0016] Add 150 g of cyclohexane and 0.99 g of dispersant Span-60 into a four-port glass jacketed reactor, and stir at room temperature. 22.5 grams of acrylic acid was placed in a beaker, and neutralized with 23.4 grams of 40% sodium hydroxide aqueous solution at 0°C. Add 2.25 g of acrylamide and 0.25 g of organically modified hydrotalcite (1 wt%) into the neutralized acrylic acid aqueous solution and stir evenly to prepare an emulsion. Finally, 0.045 grams of potassium persulfate and 0.0045 grams of N, N'-methylenebisacrylamide were added to the above-mentioned emulsion, stirred evenly, and placed in a reaction kettle. Under the protection of nitrogen, first react at 50°C for 1h, then react at 60°C for 2h, and finally azeotropically dehydrate as completely as possible at 75°C. After the reaction, filter with suction and wash with a mixed solution of water and methanol (1:9V/V) for 3 to 5 times, and dry in vacuum at 70°C for 24 hours to obtain granular poly(acrylic acid-acrylamide)/hydrotalcite nano-superabsorbent Sexual resin.

[0017] Determination of water (salt) rate: use the tea bag method to measure its water (salt) rate, weigh 0.5g of resin and place it in a 100-mesh nylon bag, and put it into 500ml of deionized water and 200ml of 0.9% NaCl solution In the beaker, after the resin fully absorbs water and swells, take out the suspension and weigh its gel quality, and then calculate the saturated water absorption (salt) rate Q (g/g) according to the formula:

[0018] Q=(m 2 -m 1 )/m 1

[0019] where m 1 、m 2 Respectively, the mass (g) of the resin before and after water (salt) absorption.

[0020] Its water absorption rate is ≥678.3g/g, and its salt tolerance rate is ≥97.3g/g.

[0021] Example 2

[0022] Same as Example 1, except that 0.5 gram of organically modified hydrotalcite (2wt%) was added to obtain the water absorption of granular poly(acrylic acid-acrylamide)/hydrotalcite nano superabsorbent resin ≥ 736.7g/g, Salt tolerance ≥121.3g/g.

[0023] Example 3

[0024] Same as Embodiment 1, the difference is that 0.74 gram of organically modified hydrotalcite (3wt%) is added to obtain granular poly(acrylic acid-acrylamide)/hydrotalcite nano superabsorbent resin with water absorption ≥ 1106g/g, resistant to Salt rate ≥ 145.3g/g.

[0025] like figure 1 As shown, use the SIRION-100 scanning electron microscope (FEI, USA) to observe the particle morphology characteristics of the material; as figure 2 As shown, in order to observe its porous network structure, the resin was fully swollen, freeze-dried and used for structural characterization (SEM, Hitachi, S-3000N; Gatan, Alto-2100), and the sample must be gold-plated before testing.