Preparation Of Carboxymethylcellulose-based IPN Hydrogels And Their Applications

Carboxymethyl cellulose(CMC) is a kind of renewable natural macromolecule. It is widely used in the fields of food industry, paper making, textile manufacturing, medicine and health, daily-use chemicals and oil industry which attribute to its good solubility in water, biodegradable, non-toxic and non-pollution characteristics. CMC is used to form various functional hydrogels owing to a large number of reactive hydroxyl groups and it is polyelectrolyte with p H sensitivity for carboxyl groups in the molecule. However, hydrogels from CMC alone always show some performance deficiency such as low mechanical strength, brittle and single properties according to current reports. To meet application requirements, CMC based hydrogels are expected to be obtained by facile preparation methods with high strength. Also, research based on the relationship between the structures and properties of CMC based hydrogels to excavating its potential applicaions is an important direction in this filed.In this thesis, two kinds of CMC based hydrogels were prepared via interpenetrating polymer network(IPN) fractional step method and IPN synchronous method respectively. Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), thermal gravity analysis(TGA) and x-ray diffraction(XRD) were used to characterize the CMC/PMA IPN hydrogels and confirmed the IPN structure as well. Their potential applications are also discussed respectively.1. CMC/PMA IPN hydrogels were prepared by fractional step in 40wt% ethanol solution with N, N’-methylenebisacrylamide(MBA) as a crosslinker, potassium peroxodisulfate(KPS) as initiator. The results showed that CMC/PMA hydrogels exhibit dense and rigid polymeric network with homogeneous skeleton structure, uniform holes and good p H responsive. CMC/PMA IPN hydrogels showed a higher thermal stability than CMC hydrogels. Simultaneously adsorption of methylene blue(MB) of the obtained IPN hydrogels was also investigated systematically. The maximum adsorption amount of the IPN hydrogel to MB reaches 2370mg/g in this work when the initial concentration of MB is 100 mg/L, adsorption lasting for 48 h at the neutral p H.2. CMC/PMA IPN hydrogels were prepared by synchronous method on the basis of fractional step method. The effects of dosage of methyl acrylate(MA) monomer and MBA to mechanical properties and thermal stability of CMC/PMA IPN hydrogels were discussed. The results showed that the higher dosage of MBA and the higher content of PMA, the higher mechanical strength and thermal stability of the CMC/PMA IPN hydrogels. In addition, adsorption on phenol experiment showed that CMC/PMA IPN hydrogel is expected to be applied in the field of organics adsorption under neutral conditions.3. CMC/CTS IPN hydrogel microspheres were prepared by IPN synchronous method and emulsification chemical-crosslinking method successfully. The CMC/CTS microspheres exhibited uniform particle size, good three-dimensional network structure and thermostability. CMC/CTS IPN hydrogel microspheres had great influence on cationic demand of white water. With the increasing of the microspheres dosage or the content of CTS in the microspheres, cationic demand decreases obviously. The preferred results is that cationic demand of white water decreases 72.89% when mCMC:mCTS=1:2, C=20g/L, T=40℃, t=15min.