Polyethylene or polythene film is usually stable and resistant to degradation. Methods are available to make it more degradable under certain conditions of sunlight, moisture, oxygen, and composting.

 

If traditional polyethylene film is littered it can be unsightly, and a hazard to wildlife. Some people believe that making plastic shopping bags biodegradable is one way to try to allow the open litter to degrade. Plastic recycling improves usage of resources. Biodegradable films need to be kept away from the usual recycling stream to prevent contaminating the polymers to be recycled. If disposed of in a sanitary landfill, most traditional plastics do not readily decompose. The sterile conditions of a sealed landfill also deter degradation of "biodegradable" polymers.

 

Polyethylene is a polymer consisting of long chains of the monomer ethylene (IUPAC name ethene). The recommended scientific name polyethene is systematically derived from the scientific name of the monomer.[1][2] In certain circumstances it is useful to use a structure–based nomenclature. In such cases IUPAC recommends poly(methylene).[2] The difference is due to the opening up of the monomer's double bond upon polymerisation.

 

In the polymer industry the name is sometimes shortened to PE in a manner similar to that by which other polymers like polypropylene and polystyrene are shortened to PP and PS respectively. In the United Kingdom the polymer is commonly called polythene, although this is not recognised scientifically. The ethene molecule (known almost universally by its common name ethylene) C2H4 is CH2=CH2, Two CH2 groups connected by a double bond, thus:

 

Polyethylene is created through polymerization of ethene. It can be produced through radical polymerization, anionic addition polymerization, ion coordination polymerization or cationic addition polymerization. This is because ethene does not have any substituent groups that influence the stability of the propagation head of the polymer. Each of these methods results in a different type of polyethylene.

 

Current plastic bag use and disposal, both by consumers and through waste management activities, not only create environmental problems, but also reinforce the perception of a wasteful society. Plastic bags as litter create a visual pollution problem, and affect our aquatic wildlife, while the heavy reliance on 'disposable' plastic bags by the American consumer raises questions of resource consumption and resource efficiency.

 

The present media debate on plastic bag use has been invigorated by reports coming from our government and environmental groups concerning the apparent success of their plastic shopping bag levy, indicating significant reductions in the use of plastic shopping bags. American Environment specialist, recognizing the community's concern, established an expert working group to provide a range of options for the National Packaging Council and governments for reducing the environmental impact of plastic carry bags.

 

The Plastic Bags Working Group found that Americans consume approximately 20 billion plastic carry bags a year, which equates to just under one bag per person per day. They concluded that plastic bags are America's highest volume 'add-on' packaging designed as a single use or disposable product and are not necessarily essential to product integrity. Approximately 53% of plastic bags are distributed from supermarket outlets, while 47% come from other retail outlets such as fast food shops, liquor stores, and general merchandising.

 

After intensive examination of the issues associated with plastic bag use and disposal, the Working Group identified four main areas of concern that it considered should be addressed by a mix of solutions:

 

Although studies show that plastic bags are numerically around 2% of the litter stream at most surveyed sites, the impact of these bags is nevertheless significant, particularly to aquatic life and in the loss of visual amenity. Plastic bags are also more noticeable in the litter stream because of their size, and because they take hundreds of years to break down. Plastic bags appear in the litter stream as a result of both inadvertent and intentional littering behaviour. Inadvertent litter is usually associated with windblown litter from disposal routes such as litterbins and landfill sites. Intentional litter results from inappropriate disposal actions by consumers.

 

The Environmental Group has identified a range of management options to address both behaviours. It recommends that current and future waste management and landfill management practices be investigated and that specific nationally consistent guidelines be developed to assist landfill operators to minimize off site litter in a variety of locations and circumstances. The Group also recommends that in the short term, active support be given to current consumer awareness and anti-litter programs, and in the longer term, that the effectiveness of the current programs be examined, with proposals being developed for a coordinated national anti littering and consumer awareness campaign, specifically focused on plastic bag use.

 

The Environmental Group has also developed management options designed to reduce, recycle and reuse plastic carry bags. To reduce the amount of carry bags used, the Environmental Group recommends the adoption and implementation by all retailers of a National Code of Practice for Management of Plastic Retail Carry Bags with defined targets and a comprehensive reporting system. It also recommends consumers shift to more durable, reusable, and recyclable bags. In parallel with the development of the Code, the Environmental Group recommends that a proposal for the introduction of a levy on plastic bags also be developed. This proposal should set out an implementation process and include a full impact assessment as required by the Council of American Governments.

 

To promote an increase in recycling, the Environmental Group recommends the National Packaging Covenant Council proceeds with its program to 'close the recycling loop' for plastic bags. It recommends that the Covenant Council investigate and develop mechanisms to improve the in-store recycling rate, and look at ways of encouraging the development of markets for the reprocessed resin, particularly the use of recycled resin in plastic carry bag production.

 

The Environmental Group, cognizant of the divergent views and experiences with degradable plastics, recommends Standards Australia commence the development of a national standard for degradable plastics. The Environmental Group also recommends that a comprehensive study on the full impact of introducing degradable bags into the American marketplace, including the effect on plastic recycling, local manufacturing, and landfills, be undertaken as a matter of priority. Some members of the Group indicated their strong support for moving to biodegradable bags if they can be clearly demonstrated to deliver preferred environmental outcomes.

 

Overall, after investigating all the issues associated with the use and impact of plastic bags and their alternatives, the Plastic Bags Environmental Group recommends that a range of short and long term complementary initiatives be undertaken, rather than one approach in isolation. Any program designed to reduce plastic bag use and eliminate litter must include a mix of approaches.

 

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