Preparation Of Polylactic Acid-based Nano-antibacterial Composite Membrane And Migration Of Nano-silver

Polylactic acid(PLA)as the main raw material.Nano silver(Nano-Ag)and nano titanium dioxide(Nano-TiO2)for nano antibacterial additives.The PLA antibacterial food packaging materials were made by solvent evaporation method.Based on thermodynamic properties,microstructure observation,mechanical properties and wettability performance test,the PLA/Nano-Ag composite film was proved more suitable for application in antibacterial preservation of fruits and vegetables.In order to study the migration rule of Nano-Ag,designing four kinds of food migration of simulation experiment.The main results were as follows:(1)PLA as the main raw material,Nano-Ag and Nano-TiO2 according to the proportion of 1%and 3%add into the PLA respectively,made the PLA/Nano-Ag and PLA/Nano-TiO2 composite film which have the antibacterial function.Through the Microwave digestion-ICP-AES method test the embedding rate of two composite film.Concluded that the Ag embedding rate in PLA/1%-Ag and PLA/3%-Ag were 0.5%and 2%.The Ti embedding rate in PLA/1%-TiO2 and PLA/3%-TiO2 were 0.1%and 0.5%.To optimize the parameters of microwave passive and the ICP-AES instrument measurement conditions.(2)Two kinds of composite films for thermodynamic properties,mechanical properties,wettability and antibacterial performance index of the test.Concluded that the Nano-Ag was more likely to be dispersed in the PLA.Under external force,the Nano-Ag/PLA composite film tensile ability better.Because Ag+ are hydrophilic group,it can quickly gathered in the composite film surface and quickly form hydrogen bonding with water molecules.So.improving the wettability of composite film.And when the Nano-Ag content is 1%,the PLA/1%-Ag composite film can reach more than 92%of the bacteriostatic rate(escherichia coli and staphylococcus aureus),get the requirements of antibacterial plastic standard.Therefore,the PLA/Nano-Ag composite film is more suitable for application in antibacterial preservation of fruits and vegetables.(3)In order to study the Nano-Ag migration rule in food.PLA/Nano-Ag composite film as matrix material.Designning with fat,acid,alcohol and aqueous food migration experiment.Migration of design temperature of 4? respectively(low temperature),28?(room temperature),40(temperature).Concluded that as the extension of the migration time,the migration rule of Nano-Ag in four kinds of food simulate fluid increase gradually and maintain a constant when reaches a certain content.The higher the temperature,the shorter time reach balance,the bigger migration amount.The Nano-Ag migration rate from high to low:N-hexane>4%Acetic acid>65%Ethanol>Distilled water.With the increase of Nano-Ag embedding rate,mobility was not as synchronous growth.As a result,the migration rate in PLA/1%-Ag>the migration rate in PLA/3%-Ag.