硕士论文的摘要
ABSTRACT
For the functionalization of polysaccharide hydrogels, three kinds of environment-friendly hydrogels, dextran hydrogel(Dex), carboxylmethyl dextran hydrogel(CMDex) and carboxylmethyl dextran-based hydrogel(CMDex/NIPA), were used as the matrixes of the hybrid materials and the templates to synthesize silver nanoparticles in the hybrid materials.UV-visible, TEM and XRD analyses were used to characterize the silver nanoparticles formed in the hydrogels.The antibacterial and catalytic properties of silver nanoparticles/hydrogel hybrid materials were also examined.
The results showed that spherical silver nanoparticles with narrow size distribution were formed in three kinds of hydrogel matrixes.For the silver nanoparticles/dextran hydrogel hybrid system, because of the existence of reducing groups (-CHO) in dextran chains, highly stable and uniformly distributed silver nanoparticles in the range of 20-30 nm can be prepred directly via in situ reduction of silver nitrate without adding any reducing agent.The size and content of silver nanoparticles formed in the hybrid materials were modulated by the concentration of AgNO3, temperature and the cro-linking density of the hydrogels.Silver nanoparticles can also be obtained in the hybrid materials using the other two modified dextran hydrogel systems by the addition of ascorbic acid as the reducing agent.Because of the good water-absorbing ability of CMDex, full swollen hydrogel networks could provide large free space for the production of large silver nanoparticles.Therefore, the sizes of silver nanoparticles produced were about 50 nm.Silver nanoparticles with the size range of 50-60 nm were obtained using CMDex/NIPA hydrogel as the template by changing the cro-linking density of the hydrogel networks.
The antibacterial and catalytic properties of the three silver nanoparticles/hydrogel hybrid materials were examined.The results proved that all of the three hybrid materials have good antibacterial and catalytic performances.This study has provided a way for adjusting the size of silver nanoparticles and preventing them from congregating in the hybrids.The obtained sivler nanoparticles/hydrogel hybrid materials have widely potential applications.
期刊论文的摘要
ABSTRACT：A type of novel hybrid hydrogels from sodium humate(SH), polyacrylamide (PAM), and hydrophilic Laponite clay were prepared using potaium persulfate (KPS) as the initiator andN , N\' – methylenebisacrylamide (MBA) as the cro-linker.The morphology of the hydrogels was characterized by Field Emiion Scanning Electron Microscope (FESEM).The adsorption-desorption kinetics of methylene blue (MB) were also investigated.It was shown that SH/PAM/Clay hydrogels exhibited excellent performance in MB adsorption.The maximum absorption concentration of MB was 800 mg.l-1 per gram of hydrogel.The adsorption concentration of hyrdrogels increased with increasing SH or clay content.Le MB were desorbed with increasing SH content, while the clay content had no significant influence on the amount of MB desorbed.This effect was attributed to the formation of a ionic complex between the imine groups of MB and the ionized carboxylic groups of SH.MB diffusion proce was dominant in MB desorption.
