What is d2w (biodegradable plastic)?
d2w is the brand for controlled-life plastic technology which is designed to control and shorten the life of normal plastic products and packaging. d2w is a carefully researched and tested additive formulation which is added to normal plastic at the extrusion or casting stage of manufacture.
Symphony’s d2w formulation is so effective that it needs normally to be included at only 1%, resulting in considerable savings in cost, transport, and storage.
PE and PP are hydrocarbons, and their molecular backbones are constructed of hydrogen atoms bonded together by carbon atoms in long entangled chains. It is these long chains that provide flexibility, strength and significantly prevent oxygen from attaching to the carbon and hydrogen atoms and causing oxidation; which in turn leads to degradation.
A no-change added-value solution
- No need to change designs or suppliers – just add d2w!
- d2w converts ordinary plastic at the end of its useful life into a material with a completely different molecular structure. At that stage it is no longer a plastic but has become a material which can be bio-assimilated in the environment in the same way as a leaf.
- Heat, light and stress accelerate the process – but are not essential.
- d2w plastics are not currently marketed as compostable, nor are they intended to degrade under anaerobic conditions in landfill.
- They can be recycled with other oil-based plastics – unlike “compostable” plastics, which will ruin a normal plastic recycling process.
Why choose d2w Controlled-life Plastic?
|Normal plastic||d2w Controlled-life Plastic Technology|
Responsible use of plastic – The Three R’s
REDUCE: a plastic bag can hold 2,500 times its own weight, and d2w can help further reduce the burden of plastic waste in the environment.
RE-USE: products made with d2w can be re-used many times during their service-life.
RECYCLE: d2w-based products can be recycled and made from recycled polymers (see Recycling Position Papers)
How does d2w Controlled-life Plastic work?
Stage 1: d2w additive is included in the basic polymer resin during the manufacturing process.
Stage 2: d2w breaks the molecular chains so that at the end of its predetermined service life the plastic starts degrading in the presence of oxygen by a process of oxidation, which is accelerated by light, heat and stress.
Stage 3: Finally bio-degradation is completed by micro-organisms.
The molecular mass of a material can be a good indication of the complexity of its molecular chains and thus resistance to oxidation.
Molecular mass is the weight of the atoms that make up an individual molecule of the material. So, for example, water is two hydrogen atoms and one oxygen atom – H2O. The atomic mass of hydrogen is 1.00784 and that of oxygen is 15.9994; therefore, the molecular mass of water with formula H2O is (2 x 1.00784) + 15.9994 = 18.01508. One molecule of water weighs 18u, but the molecular mass of a typical polyethylene is 300,000.
The d2w formulation is in the form of a metal salt. After a period of planned stability due to the anti-oxidants contained in the d2w formulation it causes a breakdown of the carbon-carbon bonds in the molecular chains – i.e. chain cleavage, or scission. The plastic product will become brittle and disintegrate into tiny flakes. As the chains continue to reduce in size, oxygen is permitted to bond with the carbon and produce CO2. The molecular mass descends to below 40,000u and at that stage, the material effectively becomes water wettable and micro-organisms can access the carbon and hydrogen.
This stage can accurately be described as bio-degradation. At this point the material is no longer a plastic but has become a material capable of bio-assimilation. It is sometimes argued that biodegradable plastics are undesirable because their components are designed to be deliberately and totally lost. This is certainly true of hydro-biodegradable or “compostable” plastics. This is because they cannot comply with EN13432, ASTM D6400, ISO17088, Australian Standard 4736-06 and similar standards unless 90% of the material converts to CO2 gas within 180 days.
However, this criticism is not true of oxo-biodegradable plastics products. If people want to mechanically recycle them, or re-use them time and time again during their useful life (usually at least 18 months), then that is practicable, and they cost very little if anything more than conventional products.
It is well known that there is a “plastic soup” of waste floating in the Pacific Ocean which now covers an area greater than the size of Texas. If all short-life plastics had been made with d2w – this environmental menace would be very much smaller.