Optimized synthesis and swelling properties of a pH-sensitive semi-IPN superabsorbent polymer based on sodium alginate-g-poly(acrylic acid-co-acrylamide) and polyvinylpyrrolidone and obtained via microwave irradiation

Abstract

A pH-sensitive superabsorbent hydrogel composite, sodium alginate-g-poly(acrylic acid-co-acrylamide) in the presence of polyvinylpyrrolidone (PVP), was prepared using the semi-interpenetrating polymer network (semi-IPN) technique and microwave irradiation. Potassium peroxodisulfate (KPS) was used as an initiator, N,N,N′,N′-tetramethylene diamine (TEMED) as a reaction accelerator, and N,N′-methylene bisacrylamide (MBA) as a crosslinker. The Taguchi method was employed to optimize the synthetic conditions for the hydrogel based on water absorbency. The Taguchi L 9 (3 4 ) orthogonal array was selected for the experimental design. The mass concentrations of MBA (C MBA ), KPS (C KPS ), and sodium alginate (C NaAlg ) as well as the molar ratio of acrylamide to acrylic acid (R AM/AA ) were chosen as the four factors in the design. Based on an analysis of variance in the test results, the optimal conditions were found to be 0.18 g/L of MBA, 0.60 g/L of KPS, 7.73 g/L of NaAlg, and R AM/AA = 1:1. The maximum water absorbency of the optimized hydrogel was found to be 1551 g/g. The relative thermal stability of the hydrogel in comparison with sodium alginate was proven using thermogravimetric analysis. The prepared hydrogel was characterized by FTIR and scanning electron microscopy (SEM). The influences of environmental parameters such as the pH and the ionic strength of the solution on the water absorbency were also investigated.

Superabsorbent hydrogel made of NaAlg-g-poly(AA-co-AAm) and rice husk ash: Synthesis, characterization, and swelling kinetic studies

“…Superabsorbent hydrogels (SHs) are water insoluble three-dimensional crosslinked polymer network that can absorb and retain great amount of aqueous solutions or biological fluids within own structure even under certain pressure (Bao, Ma & Li, 2011;Tally & Atassi, 2015). The good swelling and water retention capacity as well as desirable biodegradability of SHs make them able to be applied in various fields such as agriculture (Curcio & Picci, 2008), hygiene products (Kosemund, Schlatter, Ochsenhirt, Krause, Marsman & Erasala, 2009), wastewater treatment (Kaşgöz, Durmuş & Kaşgöz, 2008), tissue engineering (Wang, Strand, Du & Vårum, 2010), and drug delivery systems (Merino, Martín, Kostarelos, Prato & Vázquez, 2015).…”

Microwave-Assisted Synthesis of a Semi-interpenetrating Polymer Network Slow-Release Nitrogen Fertilizer with Water Absorbency from Cotton Stalks

“…To solve these problems, the semi-interpenetrated polymer network (semi-IPN) was introduced. Semi-IPN is a way of blending two polymers, in which the linear polymer chains are diffused into a preformed polymer network to produce an additional noncovalent interaction between the two polymers without forming chemical bonds . The product generated by the semi-IPN technology usually exhibited surprising performances superior to either single polymer, namely, the semi-IPN structure can improve the swelling capacity, mechanical stability, and the specific surface area of the product .…”

A Bio-Based Hydrogel Derived from Moldy Steamed Bread as Urea-Formaldehyde Loading for Slow-Release and Water-Retention Fertilizers

“… 26 Parts of the N released could be confined in the hydrogel due to the improved internal surface area and well-developed pore channels of SBS- g -P(AA/AM). 27 Xiang et al also reported similar results for a UF-loaded kaolin- g -poly(acrylic acid- co -acrylic amide) hydrogel in soil. 8 …”