Preparation Of VAE/MMT Nanocomposite Waterborne Barrier Coatings

Coating technology is a simple and effective way to improve the barrier properties of polymer packaging materials with the advantages of simple process,high production efficiency and non-toxic environmental protection.In this work,the water-based nanocomposite barrier coatings of VAE/MMT were prepared to improve the barrier property of polymer packaging material.First,the coating grade VAE emulsion and MMT silicates were selected as film-forming matrix and inorganic filler respectively with water as a dispersant.The nanocomposite barrier coatings were prepared by mixing and ultrasonic processes with the addition of coating additive.The influences of the amount of MMT and PVA on the properties of the coatings were discussed.Testing results show that the addition of MMT will reduce the water absorption by 64.25%and increase the amount of residual carbon.The coating is still stable in acid,alkali and salt with good hydrophobicity,thermal stability and corrosion resistance.PVA can increase the smoothness of coatings by reducing the polarity,VAE/MMT coatings shows flame retardant effect,by comparing PMMA coated by VAE/MMT with PMMA of decreasing heat release and C02 emissions rate of 48.9%and 56.7%respectively.Second,the KH550,KH560 and KH570 were used to modify MMT in order to improve the compatibility of MMT with VAE and the dispersion of MMT in the coatings.The VAE/OMMT nanocomposite barrier coatings were prepared by blending modified MMT with VAE emulsion.The FTIR and XRD testings showed that both the KH550 and KH560 can be successfully grafted onto the MMT surface and enter the interlayer to expand the spacing of the MMT layer.Due to the demulsification of VAE emulsion by the amines in KH550 with,the KH560 was chosen to modify montmorillonite.Finally,the VAE/MMT-KH560 nanocomposite coatings were coated on the PET films.The performance testing showed that:the coated PET films have good transmittance of 67.2%after coated with 0.5 ?m coating thickness,good barrier properties with decreasing the WVTR and OTR of PET films by 81.8%and 95.3%when total coating concentration is 1%,and the weight ratio of m(VAE):m(MMT-KH560)=1:1.