Separation methods are still not efficient. An example is
media density as the fundamental for separation and/or
preconcentration in the recycling of plastics, but the current
use of static media processes limits the capacity and
size of material that can be treated commercially. To improve
the commercial recovery of recyclable plastics, Gent
et al. [69] in 2009 reviewed cylindro-conical and cylindrical
cyclone-type media separators (such as those used for
processing coal) and suggested their use as a potential substitute.
Another example that was explained in detail in
Section 4 regarding the recycling of PET mixed with PLA,
is the limitations of NIR sorting systems, not only their difficulty
in identifying polymers with special colours or
structures, but also their high cost. Finally, the introduction
of LCA and systems analysis throughout the design, use
and recycling of bioplastics and biocomposites makes it
necessary ultimately to guarantee their sustainability as
suitable alternatives to traditional plastics and composites.
To maximise the effective use of ‘green’ plastics, it is
important to prepare for their recycling through a suitable
labelling system and initiatives to increase public awareness
and education about different types of plastics [114].
As a general short final conclusion, research on the recycling
of bio-based materials, especially bio-blends and biocomposites,
is still at a preliminary stage and lacks a deep
understanding of the different factors affecting the performance,
economy and sustainability of recycled bioplastics.