▎ 摘　　要

NOVELTY - Packaging film comprises 125-130 pts. wt. pineapple leaf fiber, 6-6.5 pts. wt. composite cellulase enzyme, 2.8-3 pts. wt. nano-magnesium oxide particles, 4.4-4.5 pts. wt. citric acid, 19-20 pts. wt. welan gum, 26-28 pts. wt. pullulan, 4-5 pts. wt. nano-graphene, 4-5 pts. wt. ethylene glycol, 9-10 pts. wt. lentinan, 19-20 pts. wt. cellulose, 5-6 pts. wt. dimethyl silicone oil, 4-5 pts. wt. propyl gallate, water and de-ionized water. USE - Used as packaging film. ADVANTAGE - The packaging film has high resistance to stress, good salt tolerance, good acid-base stability, high thermal stability and biodegradability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing packaging film, comprising (i) drying pineapple leaf fiber, crushing using a crusher for 30 minutes to cotton shape, then uniformly mixing and stirring to obtain slurry by adding citric acid and water (4 times), heating slurry to 60 degrees C, continuing enzymolysis for 40 minutes by adding composite cellulase enzyme, carrying out vacuum-filtering and washing with water, to obtain purified pineapple leaf fiber, adding nano-magnesium oxide particles and deionized water (10 times) to pineapple leaf fiber, then subjecting to high-pressure homogenization mechanical treatment at 700 bar for 30 minutes, treating at 1400 W for 50 minutes, to obtain homogeneous mixture, carrying out intermittent steam explosion blasting treatment of the homogeneous mixture for 5 times each time for 10 minutes, to obtain nano cellulose solution of pineapple leaf; (ii) mixing welan gum, ethylene glycol and deionized water (0.5 times), heating and stirring at 100 degrees C for 40 minutes, adding nano-graphene for 10 minutes, to obtain nano-graphene modified rubber, adding polysaccharide of pullulan, heating and stirring for 20 minutes at 60 degrees C, cooling, grinding and drying to obtain blended modified pullulan polysaccharide; (iii) adding nano-cellulose solution of pineapple leaf, obtain blended modified pullulan polysaccharide with the remaining raw materials (3-4 times), emulsifying the mixture by microwave at 350 W for 3 minutes, to obtain emulsified homogeneous membrane solution, where the ultrasonic power is 1000 W, and emulsification shearing rate is 15000 rotations/minute; and (iv) spreading emulsified homogeneous film solution on the glass substrate with the film thickness of 1 mm, drying under constant temperature in an oven at 50-55 degrees C under humidity of 55-60% for 3-4 hours.