Degradable Plastic is an oil based plastic containing a chemical additive that undergoes significant change in its chemical structure causing large polymer molecules to break down into smaller molecules or particles.
Biodegradable Plastic is a degradable plastic in which the degradation results from the action of naturally occurring microorganisms such as bacteria, fungi, and/or algae.
There are two primary differences between ‘degradable’ and ‘biodegradable’. Firstly, heat, moisture and/or UV exposure most often causes the degradation of a degradable product, whereas microorgganisms degrade a biodegradable product. Secondly, degradable products tend to take much longer to break down into carbon dioxide, biomass and water.
When degradable plastics break down into smaller molecules, eventually they will be small enough to be consumed by microorganisms and so biodegradation occurs. In essence then, all degradable films will eventually biodegrade but at different speeds.
There are mainly two options available to make normal Polythene into Biodegradable film and these are as detailed below:
It is made from corn (maize), potatoes or wheat. This form of biodegradable films meets the ASTM standard (American Standard for Testing materials) and European norm EN13432 for compostability as it degrades at least 60% within 180 days or less.
These materials predominantly require an active microbial environment such as municipal compost before they will degrade. The heat, moisture and aeration one gets in a compost pile are vital to this type of biodegradable film working well.
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Typical Application area: Municipal/Local authority compost system.
Films made out of blending an additive to provide UV/Oxidative and then Biological mechanism to degrade plastics film typically in 6 months to 2 years in a landfill site and/or standard composting system.
In this, biodegradation is a two stage process in which, first the plastic is converted by reaction with oxygen (light, heat and/or stress) to molecular fragments that are water wettable and second, these smaller oxidized molecules are biodegraded. (converted into carbon dioxide, water and biomass by microorganisms)
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Typical Application area:Rubbish Bags, Compost Bags, Carrier bags, Agricultural Film, Mulch Film.
We believe consumers of film need to consider 3 questions in choosing their film:
At Polybags we are urging more investment into improved recycling where possible and cost effective re-use of the same film for another purpose rather than 'managing' its degradation. In addition, we believe more research should be put into 'Energy-from-Waste' schemes popular in some other European countries.
Where customers want film that will be put into the waste stream after use and degradation is requested, our current preferred solution is film manufactured using a degrading additive. Film using this technology is currently cheaper, stronger, and more recyclable than starch based film and does offer a reasonable environmental solution to packaging waste.
Whilst we currently offer biodegradable film/bags made using an additive technology, we are researching in films which can degrade in even shorter times using either Starch based technology or Additive based, depending on the relative success of on-going technological developments.
Recycling has always been our top priority to reduce packaging waste particularly associated with plastic film/bags. The key to improvement is collection systems at point of use and sorting/contamination improvements to allow reprocessing.
All in-house scrap within POLYBAGS is recycled and POLYBAGS biodegradable film/bag can be recycled too.
Not according to the weight of evidence.
Since plastic bags are normally much thinner and lighter than comparable paper bags, it would take at least seven 45-foot trucks of paper bags to deliver the quantity of bags contained in one 45-foot truckload of plastic bags. Consequently, the use of plastic bags reduces road traffic, the resulting air pollution, and truck fuel consumption.
Polyethylene is derived from comparatively small quantities of natural gas. All plastics and chemicals use less than 10% of the total oil and gas produced in this country (most goes into transportation and heating). In contrast, paper is made by destroying trees. Both have an impact on diminishing resources and although fossil fuels are non-renewable future plastics may be made from renewable sources (in the way that we now have managed tree plantations for paper).
Plastic bags are an environmentally safe product to produce. The majority of kraft paper is made by heating wood chips under pressure at high temperatures in a chemical solution and paper production generates more air and water pollutants than plastic bags.
Paper is made by pulping wood and other materials in water. The wet material then has to have the water removed. This is done by heat and pressure. The fossil fuel required to drive the water out of one paper bag is more than the amount required to make one plastic bag.
It takes less energy to recycle a pound of plastic than it takes to recycle a pound of paper.
There's so much we all can do. We just have to do it. Here's my penny's worth:
IBAW - International Biodegradable Polymers Association & Working Groups
Online resources for a better enviornment:
