Water vapor sorption and permeability of sustainable alginate/collagen/SiO2 composite films

Films based on polysaccharides and proteins have been widely studied as possible substitutes for food packaging from fossil sources. However, its notorious sensitivity to water is still one of the primary drawbacks. In this study, sodium alginate (SA) and hydrolyzed collagen (HC) blend films containing SiO2 nanoparticles were prepared to reduce the water sensitivity. The behavior of these films regarding water vapor sorption and permeability (WVP) was reported for nano-SiO2 concentrations ranging from 2 to 10%. At each concentration evaluated, several classical mathematical models of moisture sorption isotherms were adjusted to identify the mechanisms of interactions between films and water. A reduction of approximately 8% in the film water content, and 30% reduction of WVP were observed for concentrations of nano-SiO2 higher than 6%. In addition, it was exposed that the moisture sorption exhibited a type III isotherm behavior, suggesting reduced interactions between the polymeric matrix and water vapor at low water activity. Therefore, SA/HC/SiO2 composite films could represent a simple, economical and sustainable alternative for packaging material with reduced sensitivity to water vapor.

Automated summary

Research on blend films of sodium alginate (SA) and hydrolyzed collagen (HC) containing SiO2 nanoparticles showed that concentrations higher than 6% led to significant reductions in film water content and WVP. The moisture sorption behavior exhibited a type III isotherm, indicating reduced interactions with water vapor at low water activity. These findings suggest that SA/HC/SiO2 composite films could be a simple, economical, and sustainable alternative for packaging with reduced water sensitivity.