Study On Preparation,Characterization And Properties Of Functional Materials Based On Konjac Glucomannan

Due to the good biocopatiblility,the good biodegradability and the abundant raw materials,natural polysaccharides have been paid attention by the researchers at home and abroad in recent years.In this paper,four different kinds of functional materiels based on konjac glucomannan(KGM)have been prepared via graft copolymerization,esterification reaction and etherification reaction.The characterization and the related properties of the products were also systematically studied.This study could make full use of the resources of KGM in Wulin area,and increase the extra value of KGM,as well as promote the local economy.The main results are as follows:(1)Molecularly imprinted polymers(MIPs)for caffeine based on KGM was prepared using the grafted copolymer of KGM/acrylic acid as the functional monomers,and caffeine as the templates.The structure of MIPs was characterized with Fourier transform infrared spectroscopy(FTIR)and scanning electron microscope(SEM).Moreover,the adsorption properties of the MIPs to caffeine molecular were analyzed by ultraviolet spectrophotometertometer.The result of FTIR showed that caffeine plays the role of the template molecules during the preparation of MIPs.The SEM images revealed that the surface of the MIPs is rough.The adsorption test showed that the adsorption of MIPs to caffeine molecule is good,which could be described by Langmuir equation.Furthermore,the maximium adsorption of the MIPs was 62.97mg/ml according to Langmuir equation.In addition,the MIPs have good selectivity of caffeine.(2)The grafted copolymer(KGM-g-PTMAAC)of KGM/three methyl allyl chloride(TMAAC)was prepared using KGM as raw material and TMAAC as grafting monomer.The structure of KGM-g-PTMAAC was characterized with FTIR and SEM.The thermal properties of KGM-g-PTMAAC were studied with thermal gravimetric analysis(TGA).In addition,the flocculation properties of KGM-g-PTMAAC were investigated in a kaolin suspension.The result of FTIR showed that the cationic moiety containing quaternary ammonium have been introduced in the backbone of KGM.The SEM images indicated that the surface of KGM-g-PTMAAC is rougher than that of KGM.The TGA results revealed that the thermal stability of KGM-g-PTMAAC is different with that of KGM.The results of flocculation test showed that KGM-g-PTMAAC could be potentially used as a good flocculating agent.(3)The KGM octanoate has been prepared using the KGM as raw material,the pyridine as catalyst,and the octal chloride as modifying agent.The structure of KGM octanoate was characterized with FTIR and SEM.The thermal properties of KGM octanoate was studied with TGA.Moreover,the rheological properties of KGM octanoate was investigated by the rheometer.The FTIR result showed that caprylyl has been introduced in the backbone of KGM.The SEM images showed that the microstructure of KGM octoate is loose flocculent,which is enhanced with the increase of the degree of substitution(DS).The result of TGA revealed that the thermal stability of the KGM octanoate is better than that of KGM,and which is enhanced with the increasing of DS.With the increasing of DS,the elongation at break of KGM octanoate increased,the tensile strength decreased,viscosity and water absorption of KGM octanoate reduced.The rheology analysis showed that both the storage modulus(G')and loss modulus(G")for KGM and KGM octanoate increase with the increasing of the oscillation frequency.As the temperature increased,both G'and loss modulus G" decreased.Furthermore,as the increasing of DS,they both decreased.(4)The carboxymethyl konjac glucommannan(CMKGM)was prepared using the KGM as raw material.Moreover,the viscosity behavior of the CMKGM aqueous solution was inspected.The result of FTIR showed that the crboxymethyl groups have been introduced in the backbone of KGM.The result of SEM revealed that there are a lot of dent on the surface of CMKGM.The TGA result showed the thermal stability of CMKGM is enhanced.The result of viscosity test of CMKGM in aqueous solution showed that the shear viscosity increased with the decreasing of the shear rate and the increasing of concentration of CMKGM,respectively.In Addition,the shear viscosity decreased with the decreasing of temperature,and it increased at first and then decreases with the increasing of pH.