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swelling-behaviour
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Full-polysaccharide superabsorbent hydrogels based on carboxymethylcellulose and sodium alginate
, Article Journal of Polymer Materials ; Volume 23, Issue 1 , 2006 , Pages 61-69 ; 09738622 (ISSN) ; Pourjavadi, A ; Madhavinia, G. R ; Sharif University of Technology
2006
Abstract
A novel full-polysaccharide superabsorbent hydrogel was synthesized via chemical crosslinking of carboxymethylcellulose (CMC) and sodium alginate (Alg) using epichlorohydrine (ECH) as a crosslinker. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR spectroscopy. The influence of ECH concentration and Alg/CMC weight ratio as well as reaction time and temperature on water and saline (0.9 wt% NaCl) absorbency of the hydrogels were systematically investigated. Meanwhile, the overall activation energy for the crosslinking reaction between CMC and Alg polysaccharides was estimated to be 11.6 kj/mol. Under the optimised conditions...
Effect of carbon-based nanoparticles on the cure characteristics and network structure of styrene-butadiene rubber vulcanizate
, Article Polymer International ; Volume 61, Issue 4 , 2012 , Pages 664-672 ; 09598103 (ISSN) ; Shojaei, A ; Sharif University of Technology
2012
Abstract
The network structure of styrene-butadiene rubber (SBR) in the presence of carbon black (CB) with two different structures and multi-walled carbon nanotubes (MWCNTs) was investigated. Swelling behaviour, tensile properties at various strain rates and cure kinetics were characterized. Experimental data were analysed using the Flory-Rehner model as well as the tube model theory. It is found that the network structure of CB-filled SBR follows a three-phase composite model including rigid particles, semi-rigid bound rubber and matrix rubber. This bound rubber is postulated to be critical for the mechanical and deformational properties, development of crosslinking density in matrix rubber and...