Study On Preparation And Property Of Super Absorbent Resin Of Modified Guar Gum

The preparation of modified guar gum was studied by using guar gum as material, epichlorohydrin as crosslinking agent, sodium hydroxide as catalyst and ethanol as solvent in this paper. The effect of amount of epichlorohydrin, pH, reaction time, reaction temperature and alcohol concentration on the sediment volume of cross-linked guar gum was investigated. The results showed that amount of epichlorohydrin, pH, reaction time, reaction temperature and alcohol concentration all influence cross-linked reaction of guar gum. The sediment volume decreased first and then increased with the increase of pH. It decreased with the increase of amount of epichlorohydrin, pH, reaction time, reaction temperature and alcohol concentration within the certain scope.Then the super absorbent resin of modified guar gum was prepared by using cross-linked guar gum as material, acrylamide and acrylic acid as monomers, ammonium persulfate as initiator, N,N-methylene-bis-acrylamide as the crosslinking agent by the method of aqueous solution polymerization. The effect of neutralization degree of acrylic acid, mass ratio of acrylamide to acrylic acid, mass ratio of monomers to cross-linked guar gum, amount of initiator, amount of cross-linking agent, reaction time and reaction temperature on the sucked liquid ratio of super absorbent resin, grafting efficiency, draft ratio and monomer conversion ratio was discussed. The best conditions for preparing super absorbent resin of modified guar gum are:neutralization degree of acrylic acid 80%,mass ratio of acrylamide to acrylic acid 0.8, mass ratio of monomers to modified guar gum 6:1, amount of initiator 0.8%, amount of cross-linking agent 0.3%, reaction time 3.5h, reaction temperature 65℃.The structure of guar gum, modified guar gum and super absorbent resin of modified guar gum were identified by FT-IR,TGA and DSC. The result of FT-IR testing showed that new functional groups was not introduced into the modified guar gum, but the-OH group and telescopic vibration of C-H bond became strengthen, and the super absorbent resin of modified guar gum had stretching vibration band of carboxyl and amide group through measuring and comparing the infrared spectrogram.The thermal stability increase with increasing its cross-linked degree and the super absorbent resin of modified guar gum had good thermostability.The evaluations of some influential factors such as ability of absorbent water, water retention ability, recovery properties and stability. The result of testing showed that ability of absorbent water of super absorbent resin was fast and achieved saturating in the first 15min respectively, the super absorbent resin had outstanding water retention ability and recovery properties, the effect of temperature on the absorbency of super absorbent resin was weak, and it was used in a large temperature range.