Study On The Chitosan Film And Controlled-release Fertilizer

Chitosan is a kind of natural polymer which is nontoxic and harmless with unique chemical structure and extensive sources. Because of its excellent biocompatibility, biodegradability, film forming ability, antibacterial activity and other excellent properties, in recent years, chitosan and its derivatives have been widely used in drug sustained/controlled-release systems. The study on the use and development of chitosan is a hot spot in domestic and overseas.Nowadays, chitosan has been popularly used in medicine sustained/controlled-release system. However, there is very few report about using chitosan as a sustained-release vector of fertilizer. As a sustained-release vector of fertilizer, chitosan can extend the release time of ferilizer, restrain and resist bacteria, and it is easy to dissolve, meanwhile, there is no pollution on using it. Chitosan is regarded as an excellent sustained-release material, and it will be an important research subject on future agriculture. The flexibility of pure chitosan film is poor, and easy to swell. When it was used as the film material, chitosan must be modifed by cross-linking agent, plasticizing agent and porogenic agent in order to change the property of the film to meet the effect of controlled-release.In this paper, chitosan was modified by glutaraldehyde as the cross-linking agent. Then chitosan films were prepared by solution casting method. The modifed films were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The modified film's swelling was measured. The dosage of crosslinker and the process condition for preparing controlled-release film were discussed. The results showed that chitosan and glutaraldehyde has produced cross-linked structure and the reaction between them was good. Because of the addition of glutaraldehyde, the degree of film swelling had been improved. The result of the release experiment showed that as a sustained-release vector, chitosan could effectively achieve the purpose of sustained-release.