Synthesis of responsive microcapsule (4H7MC-ECH-g-β-CD) and preparation of UV-responsive controlled-release packaging film

The synthesis of green UV-controlled release active packaging films using 4-hydroxy-7-methoxycoumarin as photosensitizing factor, β-cyclodextrin as main molecule and PLA-PVA as film-making base solution was reported. Firstly, 4-hydroxy-7-methoxycoumarin and β-cyclodextrin reacted to obtain 4H7MC-ECH-g-β-CD. 4H7MC-ECH-g-β-CD can undergo reversible photodimerization reaction at 365/256 nm in solid state. Then p-methoxybenzaldehyde/4H7MC-ECH-g-β-CD inclusion complex was prepared, investigated the loading capacity and found to be maximum at 40 ℃ and 3 h. Molecular docking proved that they formed stable inclusion complex. In the study of UV-controlled release of inclusion complex and film, it was found that the release rate of p-methoxybenzaldehyde was as follows: the release rate of samples irradiated with 365 nm < the release rate of samples irradiated with 256 nm < the release rate of samples without any treatment. This suggested that UV light can be used as a condition to control the release of p-methoxybenzaldehyde to regulate the release from inclusion complex and film.