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Influence of the initiator system on the spatial inhomogeneity in acrylamide‐based hydrogels
Author(s) -
Orakdogen Nermin,
Okay Oguz
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.24977
Subject(s) - ammonium persulfate , self healing hydrogels , monomer , acrylamide , persulfate , copolymer , polymer chemistry , redox , polymerization , potassium persulfate , radical polymerization , materials science , gel point , sodium metabisulfite , polymer , chemistry , composite material , organic chemistry , catalysis , metallurgy
The effect of the initiator system used in the gel preparation on the spatial inhomogeneity in poly(acrylamide) (PAAm) and poly( N,N ‐dimethylacrylamide) (PDMA) hydrogels was investigated by static light scattering and elasticity measurements. The hydrogels were prepared by free‐radical crosslinking copolymerization of the monomers acrylamide (AAm) or N,N ‐dimethylacrylamide (DMA) with N,N ′‐methylenebisacrylamide as a crosslinker. Two different redox‐initiator systems, ammonium persulfate (APS)– N,N,N′,N ′‐tetramethylethylenediamine (TEMED) and APS–sodium metabisulfite (SPS), were used to initiate the gelation reactions. Compared to the APS–TEMED redox pair, no significant scattered light intensity rise was observed during the crosslinking polymerization reactions initiated by the APS–SPS system. It was found that both PAAm and PDMA gels are much more homogeneous when the APS–SPS redox pair was used as the initiator. The results are explained by the formation of shorter primary chains as well as the delay of the gel point in APS–SPS initiated gel formation reactions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3228–3237, 2007