The limited availability of petroleum resources and the lack of biodegradability of plastics are the issues facing human and environment. For this reason, the production of biodegradable plastics from agricultural sources can solve these problems. Corn starch and soy protein are inexpensive, abundant, biodegradable, and nontoxic materials that interact well with each other and therefore can be used to produce biodegradable films. However, to overcome their weakness in some physical and mechanical properties, it is preferred to use in the form of a composite by employing reinforcing materials. Graphene is a two dimensional carbon nano filler with unique properties used in a variety of applications. In this study, initially, graphene and graphene oxide were synthesized by green method. The results of XRD, FTIR, and SEM were successfully confirmed the production of garphene and graphene oxide platelets. Then, the effect of adding graphene and graphene oxide platelets in the range of 0.5 to 2 % wt. content into starch/protein blend was investigated to enhance the final properties of starch/protein film. The results showed that the graphene and graphene oxide improved some properties. The modulus of starch/protein film was increased from 252 to 578 MPa by adding 0.5 % wt graphene and to 449 MPa by adding 2% wt graphene oxide, respectively. The thermal stability of CS/SPI/GO 2 composite film is more than 50 °C above the starch/protein film. The water solubility of composites by adding 2% wt graphene oxide and 0.5% wt graphene was reduced18% and 10%, respectively, compare to starch/protein films. Graphene reinforced composites films showed good barrier properties for water vapor by decreasing water vapor permeability (WVP) by 20%. In addition, the composite film with 0.5 % grapheme content had the lowest oxygen permeation rate 3.48 (cm 3 µm/m 2 d kpa) among than the other composite films.
