EMERGING ISSUE UPDATE
Issue: #2
June 2014
Conventional vs. Biodegradable Plastics
Conventional Plastics
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Plastics are typically organic polymers often containing other inorganic compounds. Plastics are most commonly derived
from petrochemicals, but some are partially natural. Raw materials to make plastics can be fossil fuels, such as crude oil, natural gas and
coal, or cellulose, salt and other materials.
There are two broad categories of plastic materials: thermoplastics and thermosetting plastics. Thermoplastics can be heated up to form
products and then if these end products are re-heated, the plastic will soften and melt again. This gives them the potential to being
recycled. In contrast, thermoset plastics can be melted and formed, but once they take shape after they have solidified, they stay solid and,
unlike thermoplastics, cannot be remelted. Hence, they cannot be recycled.
Global production of plastics in 2012 rose to 288 million tonnes – a 2.8% increase compared to 2011.
Around 5-8% of the world’s oil production is used for plastics production.
Producing 1kg of plastics generates about 3-6kg of CO2 (including production and incineration);
whereas recycling of plastic saves on average about 2.5kg CO2 per kg of plastic.
China remains the leading plastics producer with 23.9%, and the rest of Asia (incl. Japan, 4.9%) accounts
for an additional 20.7%. CO2 emissions for Asia from plastics production can be estimated between
385 and 770 million tones.
In the US, packaging applications accounted for 43% of total plastics produced in 2012. In Europe,
packaging applications are the largest application sector for the plastics industry and represent 39.4%
of the total plastics demand. Recycling and energy recovery rates for plastics packaging in Europe are Image Credit: Wikimedia Commons
higher than for other plastics, 69.2% compared to 61.9% for all plastics.
Recyclability depends on the type of plastics. Recyclable types of plastics (thermoplastics) include: expanded polystyrene (EPS), polyolefins,
polyethylene teraphtalate (PET), polystyrene, polyurethanes (PUR), polyvinyl chloride (PVC).
Biodegradable Plastics
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Biodegradable plastics can be divided into two types: plastics derived from renewable raw resources, called bioplastics, and plastics made
from petrochemicals with biodegradable additives which enhance biodegradation.
Biodegradable plastics are plastics that can be decomposed by bacteria or other living organisms. Biodegradable
means that an object can be broken down biologically to the point where microorganisms can
completely metabolize them to carbon dioxide (and water). However, the conditions under which these plastics
decompose are often very specific and depend on the composition of the plastic.
There are many different types of biodegradable plastics, which are at different stages of development. Over the
past couple of years, biodegradable plastics have steadily increased their market share. For example, in the years
2000 to 2008, the worldwide consumption of biodegradable plastics based on starch, sugar, and
cellulose – so far the three most important raw materials – increased by 600%. As of 2013, 5-10% of Image Credit: Wikimedia Commons
the plastic market focused on biodegradable polymer derived plastics.
Life cycle analyses show that bioplastics can reduce CO2 emissions by 30-80 percent compared to conventional plastics (depending on
the material and application). However, taking the whole range of biodegradable plastics, life cycle assessments that were undertaken to
determine whether the carbon, fossil fuel and water usage in these materials is more efficient than polymers made by conventional plastics
have resulted in mixed findings.
Asia has the biggest share in global biodegradable plastics production (36.2%), followed by South America (28.1%), and Europe (22.8%).
Comparison
Conventional plastics
Biodegradable plastics
Recyclability
Thermoplastics such as expanded polystyrene (EPS), polyolefins, polyethylene teraphtalate (PET), polystyrene, polyurethanes (PUR), polyvinyl chloride (PVC)
Biodegradable plastics can be decomposed by bacteria or other
living organisms into carbon dioxide (and water)
CO2 emissions
1kg of plastics generates about 3-6kg of CO2
Plastics derived from renewable raw resources (bioplastics) can
reduce CO2 emissions by 30-80 percent; other biodegradables are
not necessarily less carbon-intensive
Other environmental
concerns
Thermosets not recyclable; contaminated plastics not easy to
recycle; recycling opportunities in many countries not fully
used
Raw materials for bioplastics competing with food crops.
Read More
USEPA: http://www.epa.gov/osw/conserve/materials/plastics.htm
PlasticsEurope: http://www.plasticseurope.org/Document/plastics-the-facts-2013.aspx?Page=DOCUMENT&FolID=2; http://www.plasticseurope.org/cust/
documentrequest.aspx?DocID=46091
Bayer Material Science: http://www.materialscience.bayer.com/en/media/special/backgrounders/plastic-production
OECD: http://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=DSTI/STP/BIO(2013)6/FINAL&docLanguage=En
European Bioplastics: http://en.european-bioplastics.org/wp-content/uploads/2012/publications/Imagebroschuere_Dec2012.pdf
This update is compiled by the International Environmental Technology Centre (IETC). For any questions or comments on
this document, please contact Surendra Shrestha (surendra.shrestha@unep.org / +81-6-6915-4581).