Kraftliner paper coated with cationic starch/glycerol and poly(vinyl alcohol) blends to generate water vapor and O2 barriers

This work aimed to evaluate blend formulations with cationic starch/glycerol and poly(vinyl alcohol) for applications as a kraftliner paper coating. Blends of both polymers in 5 different proportions were tested in formulations. Uncoated kraftliner paper and double wet-and-dry paper were used as controls. The formulations were applied in two layers of 15.0 ± 0.5 g/m² on 86 ± 1 g/m² paper with a coating machine. Suspension characterization and the physical properties of the coated papers were evaluated, as well as the barrier to water, water vapor, oxygen, and oil/grease, scanning electron microscopy, and Fourier transform infrared spectroscopy following standard methods. The papers coated with cationic starch showed low water resistance. However, the blends formed with poly(vinyl alcohol) presented oxygen and water vapor barriers, reaching values lower than 10 cm³ (STP)/(m².day) and 586 ± 23 g/m².day, respectively. Combining materials can improve the barrier properties of coated papers to create biodegradable and renewable formulations, promoting sustainable packaging. [Display omitted] •Paper coating up to 75 % (m/m) composed of cationic starch showed an oxygen barrier.•Adding poly(vinyl alcohol) to cationic starch coating reduced water vapor permeation.•Poly(vinyl alcohol) in paper coating contributes to the oil barrier on folded paper.•Cationic starch improves the thermal resistance of coated paper.•Adding poly(vinyl alcohol) to the coating mixture decreases paper water absorption.