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.