This work was aimed to study the effect of natural polyphenol extract (Acacia catechu) on physicochemical properties of starch/PVA-based film. Acacia catechu extracts were incorporated in the starch/PVA- (60？:？40%) based films at different concentrations (0.1% to 15%) to the total weight of starch/PVA-based film. The tensile strength (TS) of the starch/PVA blend film was 24？MPa and significantly increased (33.8？MPa) by the addition of acacia (0.5%). Different percentages of urea (1% to 15%) were incorporated in the starch/PVA/acacia-based film. The best tensile strength (11？MPa) and elongation at break (59%) were obtained at 5% urea concentration. This 5% urea-incorporated film was irradiated at different radiation doses; the film showed the best results at 100 krad (tensile strength 15？MPa and elongation at break 69%). Molecular interactions due to incorporation of Acacia catechu were supported by FTIR spectroscopy. Thermal properties (TG/DTA) of all the films were carried out successfully. Water absorption trend of all the films was comparatively high. Urea-incorporated film degraded 94%, and irradiated urea incorporated film degraded 91% within 70 days into the soil. 1. Introduction Pure starch lacks the tensile strength, processability, and dimensional stability, and when in a starch/PVA blend film, the percentage of starch is higher than PVA; the tensile strength of the film is relatively poor. Other effective means commonly used to modify the PVA/starch composites in order to improve their mechanical and water resistance properties include (1) chemically modifying PVA or starch [1], for example, esterification, oxidation, etherification, cross-linking, and methylation [2–8], (2) physically modifying the SP (starch/PVA) composites, for example, by adding corn fibers to the blends [9], or (3) chemically modifying the SP composites during or after the blending process, for example, cross-linking reactions, grafting [10, 11]. Examples of cross-linking reagents include glutaraldehyde [12], boric acid [13], and epichlorohydrin [14], and those of methods include radiation [15] and photo-cross-linking [16]. However, cross-linking agents such as those mentioned above are costly and sometimes display toxicity. Thus, their potential applications in biodegradable packaging material are limited. Catechu (or Khair), a hot water extract of red heartwood of Acacia catechu [17], is a brown-colored material with a bitter taste. It belongs to the family Leguminosae-mimosaceae. It has some medicinal values and is abundantly grown in the region of South Asian
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