Fuente: WIPO "tomato" The present invention provides a preparation method for biodegradable polymer nanocomposite films with superior gas barrier, tensile properties, and dimensional stability at the retort temperature utilizing a one-step-reactive compounding process to achieve improved interaction between a biodegradable polymer, which is an aliphatic-aromatic copolyester based on the monomers 1,4-butanediol, adipic acid, terephthalic acid, succinic acid, and lactic acid in the polymer chain, and nanoparticles, including layered silicate type nanoclay and Metal Organic Framework (MOF). Various biodegradable polymers, such as PBAT, PLA, PHA, PBS, PCL, and PHBV, can be used as the supportive outer layers in a nanocomposite multilayer films, providing versatility in applications. The one-step-reactive compounding method offers an economical and environmentally friendly approach for the preparation of these advanced biodegradable polymer nanocomposite films.