Electrospun Polybutylene Succinate Coatings for Sustainable Cardboard Packaging: Structure-Property Relationships

Producing thin biopolymer-coated paper and cardboard is essential for a large range of applications, such as food packaging, as it allows to maintain flexibility while reducing the environmental impact and enhancing barrier properties. This study investigates electrospinning to generate polybutylene succinate (PBS)-coated cardboards with contrasted structures (i.e., different thicknesses of the individual layers). Four contrasted structures of PBS-coated cardboards are produced, presenting low polymer thickness remaining on top of the substrate (10 to 25 µm) but differing in the thickness of their characteristic layers (including the impregnated layer). The effect of the electrospinning parameters (deposition time, method (direct vs indirect)) and annealing parameters on polymer-coated cardboards' structures are investigated. The annealing pressure only reduced the coated cardboard thickness, while the electrospinning method influenced the overall structure by affecting both the thickness of the impregnated layer and of the remaining layer of cardboard. The mechanical properties tested by tensile test are maintained or enhanced after coating while oxygen barrier properties are largely enhanced for some samples. Decreasing the impregnated layer thickness resulted in a Young's modulus increase (+3 to +23%) and a decrease in stress at break (-40 to -70%), highlighting the impact of polymer-coated cardboards's structures on their mechanical properties.