Effect of blend ratio on the mechanical and sorption behaviour of polymer-polymer microfibrillar composites from low-density polyethylene and polyethylene terephthalate

The morphology of the neat blends, microfibrillar blends and the corresponding microfibrillar composites based on low-density polyethylene and polyethylene terephthalate was analyzed. As the polyethylene terephthalate concentration increased, an increase in the diameter of polyethylene terephthalate spheres/fibrils was observed. The fibrils with relatively uniform diameter distribution were obtained in the range of 15-25 wt% polyethylene terephthalate concentration. The tensile properties of the blends and microfibrillar composites increased with polyethylene terephthalate concentration up to an optimum level. The neat blends exhibited inferior tensile properties in comparison with the microfibrillar composites. As the polyethylene terephthalate concentration increased, the solvent uptake reduced. The diffusivity and permeability of the microfibrillar composites were lower than the corresponding blends. The solvent uptake was found to be lowest for the composite with 25 wt% polyethylene terephthalate concentration. The polyethylene terephthalate microfibrils in the microfibrillar composites offered a tortuous path for the diffusion of the solvent.