Preparation and swelling properties of hydrolysis-resistant superabsorbent composite based on acrylic acid and sodium bentonite

Synthesis and characterization of cationic modified starch grafted acrylic acid-based absorbent resin dust suppressant

In this paper, corn starch was used as the base material, and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride was used as a cationic surfactant to modify it. Subsequently, acrylic acid was then used as the primary raw material, and through the combined action of potassium persulfate and N,N'-methylene bisacrylamide, a cationic modified starch grafted acrylic-based water-absorbent resin dust suppressant (CACS) is synthesized via graft polymerization. During the preparation process, the water absorption performance is employed as the key indicator to optimize the process parameters: the degree of neutralization of acrylic acid is set at 50%, the corn starch dosage is 10 wt%, the volume ratio of CHPTA to acrylic acid is 1:20, the initiator concentration is 0.5 wt%, the coupling agent concentration is 0.1 wt%, and the reaction temperature is maintained at 65 °C. Under these conditions, the water absorption performance of CACS reaches 394.43 g/g. The water absorption and retention properties of the resin are evaluated, and its structure and morphology are characterized using FT-IR, SEM, TG, XRD, and other analytical techniques to validate the effectiveness of the preparation method. Furthermore, samples are prepared into solutions of varying concentrations and sprayed onto the loess surface to assess their dust suppression performance. The results indicate that the soil sample treated with a dust suppressant concentration of 0.25 wt% exhibits a wind erosion resistance rate of 99.58% at a wind speed of 12 m/s and an evaporation resistance rate of 48.28% at a high temperature of 50 °C.

Comparison of Structural, Water-Retaining and Sorption Properties of Acrylamide-Based Hydrogels Cross-Linked by Physical and Chemical Methods

Two series of hydrogels based on acrylamide and its copolymers with acrylonitrile and acrylic acid were synthesized by two cross-linking methods - chemical (using N,N'-methylene bis-acrylamide) and physical (using montmorillonite (MMT)) ones. The structure of the gels was characterized by Fourier Transform Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The swelling and sorption properties were analyzed as a function of both the monomer composition and the cross-linking method. The shift of the band corresponding to Si-O (995-1030 cm-1 ) confirmed the formation of intercalation structures for MMT-cross-linked gels. Moreover, physically cross-linked gels demonstrated a non-monotonic dependence of the swelling degree on the MMT concentration, and acrylamide-acrylic acid copolymer MMT-cross-linked gels showed pH sensitivity and the highest swelling degree of 150 g/g. The highest sorption capacity towards cadmium(II) ions was demonstrated by acrylamide-acrylic acid copolymer gels, both covalently cross-linked (30 mg/g) and MMT-cross-linked (8.9 mg/g).