Synthesis and Swelling Behavior of Super-Absorbent Soluble Starch-g -poly(AM-co -NaAMC₁₄ S) Through Graft Copolymerization and Hydrolysis

Abstract

By introducing sodium 2‐acrylamido‐tetradecanesulfonate (NaAMC14S) to graft copolymerization of soluble starch and acrylamide (AM), a novel super absorbent resin (SAR) of soluble starch‐g‐poly(AM‐co‐NaAMC14S) (SR‐14) is synthesized. Polymer gels are hydrolyzed with sodium hydroxide (NaOH) to convert the function group −CONH2 to −COO‐. The structures and qualitative changes of the polymer gels are characterized through Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), elemental analysis, and rheometer. Results show the polymer gels through the hydrolysis by NaOH increased the water absorbency of the final SR‐14 resin from 31.71 to 1183.43 g g−1 as the degree of hydrolysis (DH) increased from 0 to 80%. Drastic increases in the storage and loss modulus of SR‐14 reflected the intensive molecular structural changes induced by the addition of NaAMC14S. The changes in the molecular structures of SR‐14 can be attributed to hydrophobic associations among long‐chain alkane. Soluble starch‐g‐poly(AM‐co‐NaAMC14S) exhibits the maximum water absorbency of 2536.77 g g−1 in distilled water and 92.98 g g−1 in 0.9 wt.% NaCl solution. In the absence of NaAMC14S, however, the water absorbency of soluble starch‐g‐poly(AM) decreases to 1222.27 g g−1 in distilled water and to 62.29 g g−1 in 0.9 wt.% NaCl solution. Results indicate that NaAMC14S has potential applications as a material that can enhance the water absorbency of SAR.

Kaolin-Enhanced Superabsorbent Composites: Synthesis, Characterization and Swelling Behaviors

“…The FT-IR spectra of the ST, SA, SAP, SAPC and KL are shown in Figure 1. The FT-IR spectrum of ST is shown in Figure 1a, peaks at 1158, 1081 and 1005 cm −1 were the stretching vibration of the C-O-C bond [30,31]. After polymerization, these peaks shifted and weakened.…”

Superabsorbent Polymer with Excellent Water/Salt Absorbency and Water Retention, and Fast Swelling Properties for Preventing Soil Water Evaporation

“…For swollen hydrogel systems, according to the relative diffusion rate of water into the polymer matrix and the relaxation of the polymer chain, the diffusion mechanism of water molecules can be divided into ve types: (1) n < 0.5, pseudo-ckian diffusion; (2) n = 0.5, Fickian diffusion; (3) 0.5 < n < 1, non-ckian diffusion; (4) n = 1, Case II transmission diffusion; (5) n > 1, relaxation diffusion [49]. The equation is suitable for the initial stage of swelling process [35].…”

High crosslinked sodium carboxyl methylstarch-g-poly (acrylic acid-co-acrylamide) resin for heavy metal adsorption: its characteristics and mechanisms

“…The water absorbency of CMS-g-poly (AA-co-AM) resin with different crosslinking degrees in the deionized water was determined, and the method was referred to a literature (Lan et al 2019). Moreover, the heavy metal adsorption ca-pacity and mechanisms of the optimized resin product were observed in four solutions, including CrCl3, CuSO4, NiCl2, and ZnSO4 with a concentration of 200 mg/L.…”

“…In addition, the adsorbents are partially similar with a new functional polymer with highly insolubility character, called super absorbent resin (SAR), which have numerous hydrophilic groups, such as -COO − and -OH, and can conserve water at hundreds or even thousands of its weight. Meanwhile, in our previous research to obtain SAR by soluble starch and acrylamide under the graft copolymerization and hydrolysis reaction, we found that the water absor-bency of SAR was inversely related with the crosslinker concentration and the increase of the crosslinker concentration resulted in the decrease of water absorbency (Lan et al 2019). Based on the observation, we put forward a hypothesis that increasing the crosslinker content enormously can greatly hinder the water-absorbing expansibility of SAR, which might be conducive to material transfer process and make polymer falls back on excellent heavy metal adsorption capacity.…”