Graft copolymerization of acrylic acid onto guar gum

Abstract

ABSTRACT:The graft copolymerization of acrylic acid (AA) onto guar gum (GOH) was carried out by a peroxydiphosphate (PDP)-silver(I) system. Grafting ratio, efficiency, add-on, and conversion increase upon increasing the concentration of PDP and acrylic acid, whereas they decrease upon increasing the concentration of guar gum. Upon increasing the concentration of silver and hydrogen ions up to 2.0 ϫ 10 Ϫ3 and 4.87 ϫ 10 Ϫ2 mol dm Ϫ3 , respectively, the grafting ratio and efficiency increase but decrease upon further increasing the concentration. The increase in temperature from 30 to 45°C increases the grafting ratio but the conversion efficiency decreases. The optimum time period for graft copolymerization was found to be 2 h. The graft copolymers were characterized by infrared spectroscopy and thermogravimetric analysis.

Synthesis, swelling behaviors, and slow‐release characteristics of a guar gum‐g‐poly(sodium acrylate)/sodium humate superabsorbent

“…Both GG‐ g ‐PNaA and GG‐ g ‐PNaA/SH (15 wt %) show three‐stage thermal decomposition, and the weight‐loss rate of GG‐ g ‐PNaA is obviously faster than that of GG‐ g ‐PNaA/SH. In the initial stage, a weight loss of about 19.1% between 25 and 340°C for GG‐ g ‐PNaA indicates the loss of moisture absorbed in it, the dehydration of saccharide rings, the breaking of COC bonds in the chain of GG, and the elimination of the water molecule from the two neighboring carboxylic groups of the grafted chains due to the formation of anhydride 26. However, this process is delayed and shows a weight loss of 17.8% in the temperature range of 259–376°C for GG‐ g ‐PNaA/SH.…”

“…In the initial stage, a weight loss of about 19.1% between 25 and 340 C for GG-g-PNaA indicates the loss of moisture absorbed in it, the dehydration of saccharide rings, the breaking of CAOAC bonds in the chain of GG, and the elimination of the water molecule from the two neighboring carboxylic groups of the grafted chains due to the formation of anhydride. 26 However, this process is delayed and shows a weight loss of 17.8% in the temperature range of 259-376 C for GG-g-PNaA/SH. The successive weight losses of about 13.8% from 340 to 430 C for GG-g-PNaA and of about 8.9% in the range of 376-433 C for GG-g-PNaA/SH can be attributed to the destruction of carboxylic groups and CO 2 evolution as well as main-chain scission.…”

Synthesis and Characterization of Poly(Methyl Methacrylate) Grafted from Acacia Gum

“…Grafting efficiency (GE) and rate of grafting (R g ) were used to evaluate the graft polymerization according to the following relation as used earlier. [7][8][9][10] GE (%) = 100 . (Wg -Wn) / Wm (1) where Wg, W n , and W m are the weight of graft polymer (synthesized), natural polymer (procured) and monomer (charged), respectively.…”

Synthesis of acryloyl guar gum and its hydrogel materials for use in the slow release of l-DOPA and l-tyrosine

“…Guar gum has been modified by derivatization, grafting and network formation to improve its property profile for a wide spectrum of end-uses. The grafting of methacrylamide (Behari, Kumar, Tripathi, & Pandey, 2001), acrylamide (Singh, Tiwari, Tripathi, & Sanghi, 2004), acrylonitrile (Trivedi, Kalia, Patel, & Trivedi, 2005) and acrylic acid (Pandey, Srivastava, Tripathy, & Behari, 2006;Taunk & Behari, 2000) has been reported to affect its water retention properties. Shi and Zhang (2007) grafted poly(N-isopropylacrylamide) on O-carboxymethyl-O-hydroxypropyl guar gum and investigated the temperature induced phase transition behavior of the graft copolymers.…”