BIODEGRADABLE PLASTICS, METHOD OF PREPARATION, PLASTIC WASET,

1. BIODEGRADABLE PLASTICS
PRESENTED BY-: VIBHA
SINHA
MSC. IIIrd sem
PLANT BIOTECHNOLOGY

2. PLASTICS-
 A synthetic material made from a wide range
of organic polymers such as polyethylene,
PVC, nylon, etc., that can be moulded into
shape while soft, and then set into a rigid or
slightly elastic form.
 Now a days plastics are major pollutants .

3. BIOPLASTIC
Biodegradable plastics is plastic that
decompose naturally in the environment.
 This is achieved when microorganism in
the environment metabolize and
breakdown the structure of
biodegradable plastics .
The end result is one which is less
harmful to the environment then
traditional plastics
 A polymer derived from natural sources,
e.g corn or sugars.

4. HISTORY
Plastic was first invented in 1862
1862: The first ever man made plastic was a bio-plastic. It
was made from cellulose nitrate and wascalles Parkesine.
1924: Henry Ford uses food stock to create a bio-plastic for
car construction
1941: Henry Ford unveils the first bio-plastic car
1970’s: people demanded that research should be done on
creating a non oil based plastic because of the oil crisis
1990: A British Company called Imperial Chemical Industries
developed a bioplastic, Biopol, that was biodegradable.

5. EXAMPLES OF BIODEGRADABLE PLASTICS
Polyhydroxybutyrate
PHB is a poly(hydroxyalkanoate) (PHA), a biodegradable plastic
produced by microorganisms first discovered by Lemoigne in 1925.
Later, it was found that several other bacterial strains could also produce
PHB. Chemical synthesis has also been found by Shelton et al. Among
all, polyhydroxybutyrate (PHB) is the most common polymer . a linear
polyester of d(−)-3-hydroxybutyric acid . In general, PHB is a
semicrystalline surface-eroding polymer which undergoes hydrolytic
cleavage of the ester bonds .
L- and D-lactic acid
Many microorganisms produce lactic acid, Lactobacillus strains are
particularly useful due to their high acid tolerance and relative ease of
genetic manipulation. However, lactic acid bacteria also have
undesirable traits. They are fastidious in terms of nutrient requirements,
which often complicates product recovery, and additionally, incomplete or
negligible pentose utilization excludes the use of xylose, the second
most abundant sugar in nature, in fermentation processes.
Polystyrene to PHA
The conversion of PS to PHA was the first reported technology for the
recycling of waste plastics to a biodegradable plastic (PHA) (Ward et al.,
2006). This process involved the pyrolysis of PS to styrene oil, followed by
the bacterial conversion of the styrene oil to PHA by Pseudomonas
putida CA-3 (Ward et al., 2006). The pyrolysis (520 °C) of PS in a fluidized
bed-reactor (Quartz sand (0.3–0.5 mm)) resulted in the generation of an oil
composed of styrene (82.8%, w/w) and low levels of other aromatic
compounds.

6. MECHANISM
 Take some corn kernels.
 Process and mill them to extract the dextrose (a type of
sugar) from their starch.
 Use fermenting vats to turn the dextrose into lactic acid.
 In a chemical plant, convert the lactic acid into lactide.
 Polymerize the lactide to make long-chain molecules of
polylactide acid (PLA).
 Biodegradable plastics

8. TYPES OF
BIODEGRADABLE PLASTICS
Bio Based Plastics
These are bio or starch based plastics that are made
from soy, corn, or potatoes , breaking down 60 percent
or more, within 180 days or less. In order to do this, bio-
based plastics need water, heat, and aeration. Bio-based
plastics can take longer to decompose in landfills
because of non-availability of aeration. The bio based
plastics are non-recyclable. An example of bio-based
plastic is the cellulose fiber plastic, which is made from
reconstituted cellulose, and zein plastic, which is made
from corn protein.
Thermal Plastic
Thermal biodegradable plastic has an
additive that causes it to break down
when exposed to high temperatures. This
plastic is safe to use for foods because it is
non-toxic, and it can often be recycled.
These plastics come with an expiry date
and may start to degrade if stored in hot
temperature. They also start to degrade in
hot places like the trash bags and landfill.

9. Oxo-Biodegradable Plastic
This type of plastics needs oxygen in order to
breakdown. Oxo-biodegradable plastic is less
expensive to produce because it is easy to
make with machinery that currently
manufactures conventional plastics. When
aerated it gradually breaks down into
biodegradable fragments over a course of
several months to a few years .e.g bottles ,
carryout bags
Hydro-Biodegradable
These plastics break down when exposed to
humidity at a faster rate than oxo-
biodegradable plastic. When combined with
moisture, they expand the plastic's molecular
structure and allow the bioactive compounds
to metabolize and neutralize the plastic.
Microbial Biodegradation
Biodegradation of plastics can be achieved by enabling
microorganisms in the environment to metabolize the
molecular structure of plastic films to produce an inert humus-
like material that is less harmful to the environment. The use
of bioactive compounds, compounded with swelling agents,
ensures that the plastic degrades first into humus, and then
into carbon dioxide or methane and water, when buried. This
requires no aeration and needs nine to 19 months to break
down.

10. ADVANTAGE AND DISADVANTAGE OF
BIOPLASTICS
ADVANTAGE
Carbon emission reduction
Consumes less energy
Less landfill area needed
Recyclable
DISADVANTAGE
Need for composter
Engineering issues
Risk of contamination

11. APPLICATION
DISPOSABLE ITEMS
 Packaging
 Crockery ,cutlery
 Pots ,bowls , straw
 Used for bags, trays fruit and vegetable containers
 Egg cartons , meat packaging
 Bottes for soft drink and dairy product
NON DISPOSABLE ITEMS
 Mobile phone casing
 Carpet fibres
 Insulation car interiors
 Plastic piping
 Etc……

12. THANK-YOU
