Poly(lactic acid) nanocomposites: water barrier properties and electrospinning

The PhD thesis investigated poly(lactic acid) nanocomposite in terms of water barrier properties and electrospinning. The thesis addresses two different but related topics. The first topic is improvement of the water vapour barrier properties of PLA films. The effect of montmorillonite clay and its alignment on water vapour permeability and the effect of crystallinity (introduced by annealing) on nanoclay alignment and barrier properties were investigated (Chapter 4). PLA nanocomposites containing 0 to 5 wt.% montmorillonite layered silicate were prepared. Both amorphous and semi-crystalline PLA nanocomposite films were obtained by compression moulding. Thermal properties of the samples were measured by DSC. The nanoclay dispersion was measured using TEM and WAXD. Water vapour transmission rates through the films were measured at 38℃ and at a relative humidity of 90%. A new tortuous path model was developed to quantify the effect of crystallinity, nanoclay concentration and nanoclay alignment on water vapour permeability and showed a good fit with the experimental data from the annealed PLA nanocomposites. [Continues.]