Compatibilization and gas barrier effect of graphene nanoplatelets in PP/ EVOH blend biaxial stretching film

초록

Expanding the application scope of polypropylene (PP) by enhancing its oxygen barrier properties while maintaining recyclability is crucial for reducing plastic waste. According to recent circular economy guideline, no compatibility issues arise with PE or PP mechanical recycling when barrier materials like ethylene vinyl alcohol copolymer (EVOH) are used in concentrations below 5 wt%. In this study, 0.05-0.2 wt% graphene nanoplatelets (GNPs) were incorporated into a PP/EVOH blend as a compatibilizer. The PP/EVOH/GNP blends were biaxially stretched, transforming the EVOH dispersed phase from droplets into a layered structure, while the GNPs were more uniformly dispersed. Owing to these effects, oxygen permeability is drastically reduced, and the oxygen barrier properties are improved by 85 % in comparison to those of PP. After stretching, the nanocomposite film also demonstrated excellent water vapor barrier and mechanical properties. The biaxially stretched PP/EVOH/GNP nanocomposite film, obtained by a simple manufacturing method, shows significant potential as an economically viable and ecofriendly packaging material, offering a suitable alternative to existing barrier films.

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