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Brasil
PackTrends
2020
167
quality and new technologies
which assure biodegradability, fast compostability and
formation of non-toxic substances. Certification systems
established by the Biodegradable Products Institute –
BPI, DIN/CERTCO and other institutions validate the
performance of biodegradable materials.
According to the PMMI (PACKAGING..., 2011)
trends report 2011, “even though the concept of
compostable and/or biodegradable material has much
appeal, currently a very little package material is really
composted. There is not a significant composting
infrastructure spread over the United States. In Europe,
the European Union’s Landfill directive restricted the
biodegradable waste landfill. As a result, some European
countries have a well-established infrastructure of
composting and other does not. In Japan, a 2001
law, the Food Recycling Law, helped the increase of
composting plants and composting rates”. In Brazil,
in 2008, the composting corresponded to 0.8% of
the collected waste allotting (IBGE, 2010), which is
inexpressive, but with the institution of the National
Policy of Solid Waste, it is expected a growth of the
composting plants.
Biopolymers can be organically formed in the
nature by living organisms (agropolymers) or to be
chemically synthesized from renewable sources. The
production of biopolymer can be via polymerization of
natural molecules or chemical modification of a natural
polymer.
The agropolymers are a vegetable or animal source
biopolymer, obtained straight from the biomass. Usually
they are derived from starch (corn, potato, wheat),
cellulose, proteins (whey, soya) and from lipidicmaterials
(triglycerides). The chitosan is a natural modified
biopolymer (carbohydrate), obtained from chitin, which
is a biopolymer present on crustaceans carapace, but
it can also be found on some fungi and yeasts. Chitin
and chitosan are highly available biopolymers and their
structures allow uncountable modification possibilities,
functionalities and applications.
It has to be stuck out that the biopolymers
derived from polysaccharides (starch) have received a
lot of attention due to its compostability, good barrier to
gases and versatility. They can be used in starch blends
or mixed with cellulose, compostable polyesters, lignin,
pectin, protein or transformed into nanocomposites.
However, its high sensitivity to humidity has limited its
applications, which is very relevant in a tropical country
like Brazil, with a high environmental humidity.
The agropolymers can also be produced by
biotechnology, which means by algae and bacteria that
ferment sugars and produce polyesters (as the family of
polyhydroxyalkanoates – PHA), or by acid fermentation
that generates lactic acid, that is lately esterified
and polymerized at polyacid lactic – PLA. Algae and
bacteria can also be used to generate raw material for
biopolymer production.
Genetically modified plants have been developed
to incorporate enzymes used by bacteria in the organic
manufacturing of biopolymers. The genetic code of
bacteria has been transplanted into certain plants,
such as the soya, in order to produce the biopolymer
at the normal cellular process. After collecting it, the
biopolymer is extracted from the plant with a solvent.
Since it has been tried to improve the sustainable
profile of the agroplymers, efforts in research have been
aimed at the production of those materials from food
and beverages industry residues, agriculture residues,
and logging residues (cellulose and lignin). The issue
of the use of renewable source energy is also a relevant
requirement to reduce the environmental impact of
biopolymers when comparing to the conventional
process at the petrochemistries.
Cellulose is an organic polysaccharide composed
of long glucose chains. It is usually present in plants and
can be produced by some bacteria. It is the basic raw
material for manufacturing paper, cardboard, corrugated
paperboard, cellophane and cellulose acetate. They
can be chemically modified in aquasoluble polymer,
compatible with starch and gums.
The nanoparticles can be obtained from
biopolymers as whiskers, starch, proteins and chitin.
Chitosan nanoparticles can be used as vehicles of
specific compounds in active packages, besides its
antimicrobial property. On the other side, other inorganic
nanoparticles can be incorporated in biopolymers to
improve its properties.