Developing Acrylated Epoxidized Soybean Oil Coating For Improving Moisture Sensitivity And Permeability Of Starch-based Film

Development of biodegradable starch-based materials used for food packaging has attracted great attention since the well recognized the issues of environmental and food safety.However,compared with the conventional non-biodegradable plastics used in the food packaging industries,the starch-based films have some weakness,typically are moisture sensitivity and low water vapor barrier since the hydroxyl group containing in starch.In order to improve starch-based film characteristics,the use of bio-based modifiers and green modification technology has become a new research idea and frontier.Surface acrylated epoxidized soybean oil(AESO)-based coatings were developed to reduce moisture sensitivity and permeability of starch-based films.In this process,interface modifier was introduced to further improve the adhesion strength between starch-based film and coating layer producing a novel water-resistant starch-based material.By the methods of Fourier transform infrared spectroscopy,scanning electron microscopy,water absorption test,moisture permeability and tensile test,surface topography,cross-sectional structure,water and water vapor barrier properties,interface bonding properties,transmittance and mechanical properties of starch-based films after coating and interface modification were systematically investigated.The relationship between the microstructure and macroscopic properties of the starch composite films was established.The results showed that:The effect of AESO coating on the water and water vapor barrier properties of starch-based films was discussed.The coated AESO layer can be clearly identified as a continuous layer on the surface of the starch-based film.The water vapor permeability of the starch composite films was reduced by about 10 times,the water absorption was decreased by around 8 times,and the starch composite films can be stably existed in water for 1 hour.As the AESO concentration and initiator content increased within the range of the study,the mechanical properties of the starch composite films did not change significantly.The effect of interface modifier on the adhesion strength and water-resistant properties of starch composite films were investigated.After interface modification,the gap between the coating and the starch-based films disappeared in the SEM images.The adhesion strength was doubled and the water absorption of the modified starch composite films was reduced by about 10 times,which constituted a causal relationship with the microstructure change observed in the SEM images.With the increase of the interface modifier content in the study,the water absorption of the starch composite film decreased first and then increased.The adhesion strength and transmittance both showed a consistent increase first and then decreased.There was no significant change in the mechanical properties of the starch composite film.After coating and interface modification,the water vapor permeability was significantly reduced by about 10 times,the adhesion strength was increased by 2 times,the water absorption was decreased by around 10 times,and the mechanical property was not changed significantly.Then a safe and environmentally-friendly method for preparing water and water vapor barrier starch-based films was constructed.