Use of Epoxidized Natural Rubber (ENR) for property improvement of gelatin film

Epoxidized Natural Rubber (ENR) was incorporated into bovine gelatin film for enhancing flexibility, water-vapor barrier and water resistance of gelatin film. The impact of gelatin/ENR (G/ENR) ratios (10/0, 8/2, 6/4, 5/5 and 0/10) and ENR types (i.e. ENR-10, ENR-25 and ENR-50 containing epoxy content of 12, 28 and 57 %mol, respectively) on properties of films from bovine gelatin was investigated. As epoxy content and level of ENR increased, the films had decreased tensile strength (TS) and transparency but increased Elongation At Break (EAB) and yellowness (b*-value) (p<0.05). Water-Vapor Permeability (WVP) of gelatin-based films decreased with ENR addition (p<0.05). Incorporation of ENR-25 at the G/ENR ratio of 6/4 rendered the blend film with the increases in EAB (or flexibility) and water-vapor barrier property by approximately 1.8 and 1.3 times, respectively, compared to those of the gelatin film. The improved properties of G/ENR blend films were most likely due to the compatibility between gelatin and ENR associated with their chemical interactions, as evidenced by SEM and FTIR results.