Research On Application And Preparation Of PLA/PHB Composite Packaging Film

Bio-based degradable composite material formed by PLA and PHB were prepared using melt blending technique.Different plasticizer or solubilizing agent were added to the composite material to acquire perfect moisture permeability and oxygen transmission permeability package film which use plant essential oil as antibacterial agent.The film that used in fruits and vegetables can reduce the environment pollution and it could degrade into carbon dioxid and water completely.Changing the ratio of PLA and PHB to find a best mixed proportion.When the ratio of PLA/PHB is 70/30,the tensile strength is lower than that of neat PLA.The elongation at break increased significant from 2.86%to 3 18.41%.The film with this ratio has a moisture permeability coefficient of 9.52×10-15g·cm/cm2·s·Pa and oxygen permeability coefficient of 2.58×10-14cm3·cm/cm2·s·Pa.ATBC and GTA were used as plasticizer and PBAT was used as solubilizing agent to modify PLA/PHB composite material.The experiment show that the tensile strength of film decreased and the elongation at break increase singnificant with the increasing of ATBC and GTA.It can also find out that the oxygen and moisture mermeability coefficient were changed.DSC test show that the compatibility of PLA and PHB was improved after increased plasticizer.The PLA/PHB film blending with GTA has a stratiform structure that was seen by SEM.The film increased with PBAT show a perfect oxygen and moisture permeability coefficient when the content of PBAT is 10%.The degradation experiment was conducted to test the degrade speed of different films.The degrade speed of PLA/PHB is increaseing with the increase of PHB.The experiment show that the material contented ATBC or PBAT has a higher speed when the content of plasticizer is increasing.However,GTA has no influence on the degradation of composite film.Preservation experiment of grapes packaged with PLA/PHB/10%PBAT film added plant essential oil as antibacterial agent was conducted and use PLA/PHB/10%PBAT film and PE film as controlled groups.The experiment index such as decay rate,the grain percentage,total soluble solids and sensory suality of grapes packaged with PLA/PHB/10%PBAT film added plant essential oil show better than other groups.The decay rate and grain percentage of controlled groups increase fast after 6 day while test group present a good state which turn out the PLA/PHB/10%PBAT film has a great preservation effect on fruits and vegetables.