The Effects of Clay Platelets Orientation Achieved via a Dry Lamination Process on the Barrier Properties of Clay Polymer Nanocomposites

Clay platelets have been used to make clay polymer nanocomposite (CPN) in order to enhance the barrier properties of plastic substrates and sputtered barrier films. Clay platelets tend to be randomly dispersed and should be oriented in the film direction to achieve effective barrier properties. In this work, well-oriented nanocomposites were prepared on substrates by adopting a dry lamination process between two heated rubber rolls during the curing step. Dry lamination enabled the clay platelets to be oriented upon application before the sample was completely cured, and the final curing step froze the structure to maintain the orientation. The dry lamination time was optimized at a maximum peak of isothermal curing reaction using DSC. Through characterization via XRD and TEM, it was confirmed that clay platelets are well dispersed and exfoliated in the CPN. The CPN with highly oriented clay platelets enhanced the barrier properties to reach a water vapor transmittance rate of 5.5×10^-4 g/m²/day, while maintaining optical properties.