Developing acrylated epoxidized soybean oil coating for improving moisture sensitivity and permeability of starch-based film.

Acrylated epoxidized soybean oil (AESO)-based coatings were developed to reduce moisture sensitivity and permeability of starch-based materials. The coating was applied on starch based films by dipping the samples on AESO-based coating solutions, followed by crosslinking with ultraviolet (UV) light. Effect of AESO concentration, photoinitiator content and processing conditions on the performance of coated starch-based film was systematically investigated, in particular the effect of coating on moisture absorption, permeability and mechanical properties. The modified surface was characterized by scanning electronic microscopy and Fourier transform infrared spectroscopy. The results showed that the moisture sensitivity of the starch-based sheets was reduced significantly since the crosslinked AESO acted as a hydrophobic layer. Moisture permeability was decreased more than 10 times after AESO treatment. It was found that the crosslinking density acted as one of the key factors, so even a very thin layer of AESO could achieve good water resistance.