Superior hydrophobicity of pomelo peel film: Impact of silane integration

This study aimed to develop a film from pomelo peel (PP) to enhance its hydrophobic properties for potential use as a hydrophobic laminated layer in single-use packaging applications. The optimal ratio of 2 % PP and 4 % glycerol of PP weight film yielded the most favorable mechanical properties for the film, as demonstrated by the maximum tensile strength recorded at 11.36 ± 1.54 MPa and a Young's modulus of 143.75 MPa. Additionally, the film was further enhanced by incorporating various additives, including maleic anhydride, lignin, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS), and aminopropyltrimethoxysilane (APTMS), at concentrations of 1 % and 3 % (w/w) to the PP powder. The additives were incorporated into the bulk solution to form a dispersion during the film grafting process. Notably, the addition of 1 % AEAPTMS achieved the highest water contact angle (123°) and the slowest rate of water absorption. Fourier transform infrared spectroscopy (FTIR) analysis revealed that the increased hydrophobicity was due to the reduced presence of O–H functional groups available for water interaction. TGA and DTG confirmed the interaction between the additives and the PP film. SEM/EDS images revealed a surface and cross-section with a smooth, glossy, concrete-like appearance when lignin and both silane supplements were present. Adding 1 % AEAPTMS to the base pomelo peel film proved to be the most effective and straightforward method for enhancing hydrophobicity without sacrificing the film’s mechanical strength.