A further decrease in the film permeability (by 10–27%) was
achieved by extrusion blow moulding, the less-permeable films being obtained at a blow
moulding ratio of 4. Such a reduction in the permeability was caused mainly by ordering of
the MMT platelets within the PLA matrix during the blow moulding process, which has
been proved by transmission electron microscopy (TEM). The obtained results confirm the
effectiveness of extrusion blow moulding as a technique for manufacturing nanocomposite
films containing PLA as a matrix, which exhibit favourably modified barrier properties.