Chitosan Nano-composite Coating

The new pesticide formulation of nanometer compound membrane is take nano-TiO₂ and the chitosan as the principal constituent, reacted with the original pesticide completely, forms a thin membrane on the fruits and vegetables after spurting. This kind of dosage-form of pesticide can reduce blow flutter,evaporate,drain, enhance the adhesion and infiltration of the pesticide, , improve the ability of the water resistance. It is a sort of effective, secure, economical and convenient new pesticide formulation.The paper studies the optimal condition of modifying nano-TiO₂ powder, and the compound membrane of chitosan /TiO₂ and the pesticide with the modifying nano-TiO₂ powder is gained, and proving with the researches of mechanical properties test and antibacterial activity test.According to the researches of lipophilic degree, choose the best modified pharmaceutical of sodium laurate from three kinds of modified pharmaceutical, and optimize its dosage and the best reaction condition.The chitosan/modifying nano-TiO₂ and pesticide compound membrane is prepared with solution method. The configuration of membrane is ascertained by FTIR and TEM. And compare with the membrane of chitosan by measuring the viscosity, thickness, percent water absorption, optical transmittance, the measurements of mechanical properties and antibacterial activity. It was found that there was hydrogen bonding interactions between chitosan and nano-TiO₂. So the mechanical properties is enhanced, (longitudinal strength: 15.0%, break elongation ratio: 27.2%, right angle peel strength: 35.6%), and the antibacterial activity is also enhanced.According to the researches of antimicrobial test, it is found that the antibacterial activity of chitosan/nano-TiO₂ compound membrane and chitosan/nano-TiO₂ with pesticide compound membrane is good, such as Escherichia coli of Gram-Negative Bacteria, Bacillus subtilis and Salmonella Dublin of Gram-Positive Bacteria; Also have certain antibiosis effect on fungi, for example, yeast and penicillium; the antibacterial activity on the above-mentioned bacteria and fungi of simple pesticide that aqueous solution is not good; and the antibacterial activity on agriculture pathogen of chitosan / nano-TiO₂ compound membrane is worse than chitosan / nano-TiO₂ with agricultural chemicals compound membrane. The conclusion is that, the chitosan and nano-TiO₂ can strengthen the antibacterial result of pesticide, enhance the mechanics performance of the chitosan membrane, prolong the effect of pesticide.