▎ 摘　　要

NOVELTY - A polylactic acid composite membrane comprises a polylactic acid substrate, and a graphene barrier layer arranged on an upper surface and a lower surface of the polylactic acid substrate. USE - Polylactic acid composite membrane is useful for packaging foods, medicines and electronic devices. ADVANTAGE - The polylactic acid composite membrane is environmentally-friendly, has excellent water and oxygen barrier properties, transparency, surface gloss and appearance, and is capable of being printed on its surface. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation method of polylactic acid composite membrane, which involves dispersing graphene or its derivative in diluent and then mixing with photocurable resin and photoinitiator to prepare slurry, coating the slurry on the upper surface and the lower surface of the polylactic acid substrate and photocuring to obtain composite membrane.