Application of ftir in the determination of acrylate content in poly(sodium acrylate-co-acrylamide) superabsorbent hydrogels

Abstract

Recebido em 25/11/11; aceito em 30/1/12; publicado na web em 15/6/12 Hydrogels have been prepared by free-radical solution copolymerization of acrylamide and sodium acrylate (NaAc), with molar ratio ranging from 25/75 to 80/20, respectively, using methylene bisacrylamide as the crosslinking agent. A FTIR spectroscopy procedure to determine the acrylate/acrylamide ratio in these hydrogels was proposed based on absorbance at 1410 cm -1 (nCOO -) and 2940 cm -1 (nCH and nCH 2 ). A straight line with a good linear correlation coefficient (0.998) was obtained by plotting the acrylate content (Ac%) versus relative absorbance (A rel = A 1410 /A 2940 ). Results were confirmed by the amount of sodium cation released in acid medium determined by atomic absorption spectrometry.

Polymeric polyelectrolytes obtained from renewable sources for biodiesel wastewater treatment by dual-flocculation

“…The band at 1670 cm -1 corresponds to C=O bond stretching characteristics of the acrylamide unit. The bands at 1565 and 1408 cm -1 are due to carboxylate group stretching of acrylate [53].…”

Synthesis and Characterization of Poly(Acrylamide-Co-Acrylic Acid) Flocculant Obtained by Electron Beam Irradiation

“…At 1653-1645 cm -1 , a stretching of the C=O group from the AMD and AA unit appears in all spectra. At this wave number there is also the OH angular deformation from water, which explains the existence of this band in the polyacrylate spectrum 35 . The characteristic peak which appeared in the range of 1620-1600 cm -1 is due to the NH 2 bending from AMD.…”

“…The absorption located in the regions 3350-3330 cm -1 and 3200-3185 cm -1 corresponds to the asymmetric and symmetric NH 2 stretching vibrations from acrylamide 35,36 . On the other hand, the broad absorption bands from 3400 cm -1 to 2950 cm -1 can be assigned to the -OH from the carboxylic group 37 .…”

“…The absorption band in the region 1455-1445 cm -1 , is assigned to CH 2 stretching vibration. The absorption located in the regions 1450-1410 cm -1 has been assigned to C-N stretchingvibrations 35,36 . Bands at 1560 and 1406-1410 cm -1 are due to the symmetric and asymmetric stretching of COO − of acrylate (acrylic acid neutralized with NaOH) 34 .…”

Composite Superabsorbent Hydrogel of Acrylic Copolymer and Eggshell: Effect of Biofiller Addition

“…The hydrogels were synthesized by free-radical copolymerization following the procedure reported by Magalhães et al 22 with a few modifications. Acrylamide (1.05 g, 0.015 mol, in 1 mL) was added to 24 mL of distilled water constantly bubbled with nitrogen.…”