Study On Preparation,Characterization And Their Retention And Drainage Aid Performance Of Guar Gum Derivatives

Guar gum derivatives are derived from guar gum powder which has introducted specific functional groups after a series of chemical modification,and they are widely used in the manufacturing process for non-toxic and improving the retention and drainage effects significantly.In this paper,the preparation and characterization of cationic guar gum?CGG?and cationic carboxymethyl hydroxypropyl guar gum?CCMHPG?and amphoteric guar gum in ionic liquids and their retention and drainage aid performance in deinked pulp were studied.In order to achieve optimization of the manufacturing process parameters,the effects of CGG,CCMHPG and amphoteric guar gum on the FPR and water filtration performance were analyzed and compared,and the application effects of CCMHPG / PAC binary particles retention and drainage system were discussed.Firstly,two kinds of ionic liquids chlorinated 1-ally1-3-methylimidazole?[AMIM]Cl?and chlorinated 1-butyl-3-methylimidazole?[BMIM]Cl?were synthesized one-step using conventional heating method.And then the ionic liquids acetate 1-allyl-3-methylimidazolium?[AMIM]Ac?and acetate 1-butyl-3-methylimidazolium?[BMIM]Ac?were synthesized in two steps.The FT-IR showed the characteristic peaks of the imidazolium cation group,and the chemical shifts of each peak were also one-to-one correspondence with the four products in the ¹H-NMR and ¹³C-NMR.Secondly,four cationic guar gums were prepared in four ionic liquids using guar gum powders as raw material and 3-chloro-2-hydroxypropyltrimethylammonium chloride?CTA?as the cationic etherifying agent.It was determined that CGG synthesized in ionic liquids [AMIM]Ac had the highest nitrogen content,so [AMIM]Ac was selected as the reaction medium for subsequent experiments.The effects of the etherification agent dosage,the reaction temperature,the reaction time,the alkalization time and the alkali dosage on the nitrogen content and viscosity of the product were investigated by orthogonal experiments and single factor experiments to determine the optimum synthesis conditions.The results showed that the nitrogen content of product was 1.95%,and the viscosity value was 583 mPa·s.CGG synthesized in ionic liquids had higher nitrogen content and viscosity than that synthesized in ethanol and isopropanol,indicating that ionic liquids has a catalytic and protective effect on the etherification of guar gum.The structure of CGG was characterized by FT-IR and ¹H-NMR.The scanning electron microscopy?SEM?showed that the morphology of CGG was changed.Thirdly,CCMHPG was prepared innovatively in one step using [AMIM]Ac as the reaction medium,and CTA,sodium chloroacetate and propylene oxide as modifiers.The effects of the three modifiers' dosage,the alkali dosage,the reaction temperature and the reaction time on the degree of substitution and viscosity of the product were studied to determine the optimum preparation conditions.The results showed that the water solubility of the reaction product was good,the viscosity of 1% aqueous solution was 1072 m Pa·s,the cationic substitution degree was 0.24,the carboxymethyl substitution degree was 0.41 and the hydroxypropyl substitution degree was 0.36.CCMHPG showed an advantage in both viscosity and solubility compared to the amphoteric guar prepared under the same conditions.¹H-NMR showed that quaternary ammonium groups,carboxymethyl groups and hydroxypropyl groups were successfully grafted onto guar-gel molecules.SEM showed that wrinkles and scaly cracks were observed on the surface of the particles.Finally,compared with different kinds of CGG,the FPR of CGG-5 was the best?the addition amount of CGG-5 was 0.06%,FPR was 72.3%?.Comparing the FPR of CCMHPG with different substitution degree,it was found that adding 0.04% CCMHPG-1 could achieve the best retention effect of 77%.Amphoteric guar gum can also improve the FPR significantly,the amount increased from 0 to 0.05%,FPR increased from 46.6% to 72%.Compared with three kinds of guar gum derivatives?CGG-5,CCMHPG-1 and AGG?,CCMHPG-1 had the best retention and drainage aid performance.The CCMHPG / PAC binary system was used for deinking pulp,the retention rate was 94.3% and the beating degree was 43°SR when adding 0.8% PAC and 0.04% CCMHPG.