Epoxidized soybean oil-based paper composites (ESOPCs) were prepared by fabricating poly epoxidized soybean oil (PESO) with paper. With boron trifluride diethyl etherate as catalyst, epoxidized soybean oil was in situ polymerized on the surface of the paper and within the interspaces of the paper cellulose fibers. Fourier transform infrared analysis confirmed the polymerization of epoxidized soybean oil. Scanning electron microscopic analysis showed that ESOPCs had nanostructured wrinkle morphology on the surfaces and the PESO combined tightly with the paper cellulose fibers. The tensile strength of ESOPCs was 17.3-24.8 MPa, which was higher than that of most vegetable oil-based neat polymers. Thermogravimetric analysis indicated that ESOPCs were thermally stable up to 360 degrees C in a nitrogen atmosphere. Water vapor permeability (WVP) tests revealed that the WVP of ESOPCs was 3.52-4.45 x 10(-12) g/m/s/Pa, significantly lower than many of other biobased polymeric materials, which would promote the application of vegetable-based polymers as potential water-resistant materials. (C) 2014 Wiley Periodicals, Inc.