<![CDATA[Moisture-resistant kraft paper is important for food packaging because it helps preserve product quality and extend shelf life. However, untreated kraft paper exhibits limited barrier performance owing to the porous and hydrophilic nature of its cellulose structure. Herein, the mechanical and barrier properties of kraft paper were enhanced by applying poly (lactic acid) (PLA) coatings using a dip-coating technique with PLA concentrations ranging from 1 to 5 g/100 mL and either single- or double-dip-coating cycles. The results showed that increasing the PLA concentration and applying a double dip-coating treatment consistently improved coating thickness, tensile strength, elongation at break, water resistance, and water vapor barrier performance. The best performance was achieved with the double-dipped sample coated with 5 g of PLA, which increased the thickness by up to 17%, improved tensile strength by more than 200%, increased elongation at break by 55%, reduced Cobb water absorption by 82.45%, and decreased the water vapor transmission rate by 31.19%. Scanning electron microscopy images confirmed that high PLA loading and repeated dip-coating produced smooth and dense surfaces through fiber encapsulation, pore filling, and enhanced physical integration between PLA and cellulose fibers. These findings demonstrate that PLA-coated kraft paper is a promising biodegradable and scalable material for food-packaging applications requiring improved mechanical integrity and enhanced moisture-barrier performance.]]>
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