Preparation Process And Properties Of Cellulose Water Retention Material

With strong water-reserving capacity, water retention material(WRM) is one the newtype of functional polymer materials and has been widely used in many fields on account ofits excellent properties. A new water retention material was prepared by activation and graftmodification on the basis of hydroxyethylcellulose(HEC). The Properties and the optimumprocess conditions of preparing the product were studied in this thesis, providing an importanttheoretical basis for its further industrial application.To obtain the material with better salt tolerance and better water-reserving capacity,2-chloro-4,6–di(N,N-dimethyl-N-benzyl-1,3-propanediamine)-1,3,5-triazine(BT), as themodifier, was grafted onto HEC to add the different hydrophilic groups such as quaternaryammonium salt and amidogen, which made the hydrophilic groups of HEC diversification.The main influencing factors of the synthetic process and material performance such asactivation time, reaction temperature, the concentration of NaOH, the molar ratio of monomerto HEC and so on were researched in this paper to obtain the optimum process conditions ofpreparing the product. Besides, the pH and temperature during the imbibition tests of WRMwere also researched to conclude the optimal water absorption conditions of HEC-BT. Theperformance and repeatability of WRM were researched. At last, the structures of WRM wereconfirmed by IR, TG, XRD and SEM.The results of all the experiments are as follows: (1) The pretreatment of HEC withNaOH is a very significant impact on graft modification, which could improve the reactionperformance of HEC. The optimum conditions of activation are: the concentration of NaOH is30%; activation temperature is 50°C; activation time is 5h. (2) The optimum processconditions of preparing HEC are: reaction temperature is 75°C; reaction time is 6h; the molarratio of the monomer to HEC is 2:1. The max water adsorption ratio, the max salt-solutionabsorption ratio and the max Urine-solution absorption ratio are 251g/g, 124g/g and 130g/g respectively, with better water retention performance and repeatability. (3) The results of IRindicat that WRM prepared in this paper is the graft copolymer of HEC and BT. The results ofIR indicat that the phenomena of the graft copolymer reaction occurs not only at amorphousregion but also on the surface of HEC. The results of TG indicate that the thermostability ofthe grafted product is reduced, compared with HEC. The results of SEM indicate that thereare small and dense cavities on the surface of WRM, which reveale excellent water retentionperformance. Besides, the applied experiments indicate that there will be better capacity ofhumidity guarantee when the WRM is added to the soil.