Facile fabrication of hydrophobic cellulosic paper with good barrier properties via PVA/AKD dispersion coating

Due to the micro-sized pores on cellulosic sub-strate surface and the hygroscopic nature of cellulosic fibers, paper has poor barrier properties. Dispersion coating can improve the barrier properties of cellulosic paper noticeably by forming a continuous, non-porous polymer film on paper surface. In this work, the excellent film-forming performance of polyvinyl alcohol (PVA) was used to seal the surface pores of paper, thus enhancing the barrier properties. Alkyl ketene dimer (AKD) was also added as a coating component to improve the water resistance of paper. Results showed that after PVA/AKD coating hydrophilic base paper changed to hydrophobic one, as proved by water contact angle (WCA) measurements. The water vapor transmission rate (WVTR) of base paper decreased sharply from 543 g/m(2).day to 2 g/m(2).day in the case of PVA/AKD triple coating, where the threshold of WVTR was reached. Meanwhile, the pristinely non-grease resistant base paper converted to a product with the highest grease resistance level. Furthermore, both elongation at break and tensile strength of base paper improved markedly after PVA/AKD coating. It was concluded that these improved properties were contributed by the combined use of PVA and AKD in the coating.