A water superabsorbent resin synthesized by starch grafting acrylic acid (AA) and acrylamide (AM) and its microstructure and physicochemical property analysis

Water superabsorbent resin has widely use potential in industrial field. Nevertheless, certain drawbacks restrain design and commercial profit achieving. A core lies in an efficient balance between water absorption, degradation and “green production”. Exploring a method to prepare a material that sustaining proper water absorption, degradation and “green production” or ensuring a fine cognization on reaction mechanism is in demand. In this work, pure corn starch was irradiated by an electron beam (EB) in air then treated by AA, AM grafting. Later, microstructure and macroscopic properties were explored by FT-IR, XPS, 13 C NMR, XRD, TGA, water and NaCl solution absorption, water retention, solid residue (SR) and monomer use efficiency rate (ER) analysis. Main results reveal that a reaction temperature, period, AA neutralization level, AM-AA, (NH 4 ) 2 S 2 O 8 and N, N-methylenebisacrylamide (MBA) amounts as 60 ℃, 2 h, 80 %, M AM :M AA :M St = (05 _ 0.8):10:1, M (NH4)2S2O8 :M St and M MBA :M St as 1 and 0.1 _ 0.5 wt% is an optimized condition for starch grafting AA, AM. Grafting reaction mainly occurred at C-6 site C-OH bond, initialing severe amorphization and a thermal-decomposition temperature elevation near 120 °C. Pure water and NaCl solution absorption capabilities-( Q H2O and Q NaCl solution ) were linearly promoted vs absorbed dose. A sample- St(500 kGy)- g -AA-AM-sustaining Q H2O and Q NaCl solution as 1098 and 82.1 g/g was achieved, which is in lined with commercial use standard (GB/T 22875–2018, Q H2O ≥ 20 g/g, Q NaCl solution ≥ 40 g/g). In addition, this sample displayed rapid water absorption response, excellent water retention and monomer use rates. A period as 3 min absorption achieved more than 80 wt% water absorption capability. A 60 °C, 24 h period heating leaved off more than 40 wt% absorbed water. AA, AM use rate is close to 95 %, according to “green production” category. It seems a possessing fine comprehensive property and being cleanly produced water absorbent resin was prepared via EB irradiation and starch grafting AA, AM and reaction mechanism was presented. This prepared material possibly sustains potential commercial profit and given reaction mechanism might promote starch AA, AM grafting product design.