Porous Superabsorbent Hydrogel Composites: Synthesis, Morphology and Swelling Rate

Abstract

Summary: Novel porous hydrogel composites with very high swelling capacity and enhanced rate of water absorption were synthesized in aqueous media at room temperature under normal atmospheric conditions. The porosity was induced through either foaming conducted in the course of polymerization or non‐solvent dewatering of the as‐synthesized gels. Kaolin was incorporated as an inorganic component in the polymerization process. The foaming technique was used to form porosity using three systems of different porogens (porosity generators), i.e. sodium bicarbonate, acetone and their combination. The as‐synthesized gels were dried through oven drying and non‐solvent dewatering. Morphology and swelling rate of the superabsorbent hydrogel composites (SHCs) were studied versus either the porogen system or the drying method. It was found that the simultaneous polymerization‐foaming technique had great influence on the improvement of porosity, morphology of the porous structure and the rate of water absorption. It was also shown that the drying procedure had remarkable influence on preserving the preformed porosity. Methanol as a dewatering solvent produced SHCs with higher porosity and swelling rate in comparison with the porosity of the hydrogels dewatered in acetone. Our invented methodology including simultaneous polymerization and foam formation using dual‐porogen system and the subsequent methanol‐dewatering approach was found to be the most efficient, highly practical, and cost‐effective route for preparing improved superabsorbing hydrogel materials.

Fast‐swelling oxidized starch phosphate–poly(acrylate/acrylamide/2‐acryloylamino‐2‐methyl‐1‐propanesulfonic acid) superabsorbent composite

“…The results indicate that the IR spectra of potato starch in Fig. 1a contain the OAH stretching absorption at 3408 cm 21 . The band at 2927 cm 21 corresponds to m CH , which is confirmed by d CH at 1463 and 1376 cm 21 .…”

“…The sample powders were mixed with KBr and pressed into discs for the infrared measurement. Transmittances were recorded between in the range of 4000 and 400 cm 21 .…”

“…1a contain the OAH stretching absorption at 3408 cm 21 . The band at 2927 cm 21 corresponds to m CH , which is confirmed by d CH at 1463 and 1376 cm 21 . The band peak at 1655 cm 21 was assigned to AOHÁÁÁO-bending of the intramolecular hydrogen bond.…”

Optimization of synthetic conditions CMC-g-poly (acrylic acid)/Celite composite superabsorbent by Taguchi method and determination of its absorbency under load

“…The introduction of inorganic fillers to a polymer matrix increases its strength and stiffness properties. Recently, much attention has been paid to inorganic materials for the preparation of superabsorbent composites, such as montmorillonite [4,5], attapulgite [6,7], kaolin [8,9], mica [10,11], bentonite and sercite [12,13]. Mineral powders of Celite are hydrated layered aluminosilicates with reactive -OH groups on the surface.…”

Synthesis and properties of methacrylic acid based hydrogels modified with zeolites

“…Takvo ponašanje može da se objasni stvaranjem dodatnog fizičkog umreženja, prostim zauzimanjem slobodne zapremine u polimernoj matrici ili nastankom interakcija polimer-neorgansko punilo. Trend opadanja SD eq sa porastom koncentracije punila u kompozitima polimer/neorgansko punilo zabeležen je i za mnoge druge sisteme [283]. Kinetika bubrenja kompozita PMAA/zeolit u puferima pradena je na uzorcima sa 0 mas%, 15 mas% i 30 mas% zeolita.…”