52
3 Chitin
Chitin producers
Waste
processors/
agents
Other shell
waste
applications
Chitin
distributors
and
suppliers
Chitin based
product
manufacturers
Shell waste generators
Fig. 3.4 Illustration of the value chain of chitin production
Combining chitosan with other polymers significantly improves its applicability
as a packaging material. A recent example of this is the clear plastic film of chitosan
combined with other biodegradable polymers, cellulose and polylactic acid (PLA).
A synergistic effect can be achieved between two polymers, in this case chitosan (a
main chitin derivative) and cellulose (the most abundant natural polymer on earth).
A multilayer film made of chitosan nanofibers and cellulose nanofibers coated on
polylactic acid achieved a film with up to 73% lower oxygen permeability than when
the film is made with PLA only. This is also a significant improvement to films made
up of chitosan or cellulose alone (Satam et al. 2018).
While PLA is a naturally derived polymer sourced from lactic acid obtained
from milk or bacteria, it is non-toxic, biodegradable and biocompatible; however
on its own, it has poor film-forming properties. On the other hand, chitosan forms
excellent films; however, it has much higher oxygen and water vapor permeability, and these are not desirable for applications such as food packaging where the
food or drug or electrical component needs to be dry and airtight at least over the
duration of storage. Cellulose, although hydrophobic, has poor film-forming properties but forms anionic nanofibers with good mechanical strength. By combining
the cationic chitosan nanofibers and anionic cellulose nanofibers and spraying layer
by layer unto polylactic acid films, a composite film with low oxygen permeability
and moderate mechanical property is formed. Alternating three layers of chitosan–
cellulose–chitosan nanofiber layers on a PLA layer produced films with the least
oxygen permeability and haze resulting in transparent packaging films with excellent physicochemical properties that rival those of petroleum-sourced transparent
films. Other methods of creating chitosan composite films include solvent casting
and spin coating.
3 Chitin
Chitin producers
Waste
processors/
agents
Other shell
waste
applications
Chitin
distributors
and
suppliers
Chitin based
product
manufacturers
Shell waste generators
Fig. 3.4 Illustration of the value chain of chitin production
Combining chitosan with other polymers significantly improves its applicability
as a packaging material. A recent example of this is the clear plastic film of chitosan
combined with other biodegradable polymers, cellulose and polylactic acid (PLA).
A synergistic effect can be achieved between two polymers, in this case chitosan (a
main chitin derivative) and cellulose (the most abundant natural polymer on earth).
A multilayer film made of chitosan nanofibers and cellulose nanofibers coated on
polylactic acid achieved a film with up to 73% lower oxygen permeability than when
the film is made with PLA only. This is also a significant improvement to films made
up of chitosan or cellulose alone (Satam et al. 2018).
While PLA is a naturally derived polymer sourced from lactic acid obtained
from milk or bacteria, it is non-toxic, biodegradable and biocompatible; however
on its own, it has poor film-forming properties. On the other hand, chitosan forms
excellent films; however, it has much higher oxygen and water vapor permeability, and these are not desirable for applications such as food packaging where the
food or drug or electrical component needs to be dry and airtight at least over the
duration of storage. Cellulose, although hydrophobic, has poor film-forming properties but forms anionic nanofibers with good mechanical strength. By combining
the cationic chitosan nanofibers and anionic cellulose nanofibers and spraying layer
by layer unto polylactic acid films, a composite film with low oxygen permeability
and moderate mechanical property is formed. Alternating three layers of chitosan–
cellulose–chitosan nanofiber layers on a PLA layer produced films with the least
oxygen permeability and haze resulting in transparent packaging films with excellent physicochemical properties that rival those of petroleum-sourced transparent
films. Other methods of creating chitosan composite films include solvent casting
and spin coating.