Research on improving the surface hydrophobicity of paper coated by poly-vinyl alcohol -itaconic acid grafting copolymer

Biodegradable surface sizing agent(poly-vinyl alcohol/itaconic acid/acrylamide)was synthesized via radical polymerization with MINITAB software. Fourier transform infrared spectroscopy and scanning electron microscopy were used to evaluate the structure of the surface sizing agent. In the meantime, a thin layer of PVA or PVA/IA/AM was coated on the surface of paper. The strength and water resistance of paper were studied and compared. The optimization experiment condition for the surface sizing agent was determined by Design of Experiment (DOE). It indicated that PVA/IA/AM copolymer not only improve the hydrophobicity of paper but also increase the paper surface strength. It was attributed that PVA/IA/AM could form the hydrophobic coating layer with spatial network structure on the surface of paper and increase the number of hydrogen bonding between the copolymer and fiber. Furthermore, the copolymer had better forming film characteristic and lower property of penetrating into the interior of paper than PVA when they were coated on the surface of paper.