Bioplastic Product & Biodegradable

A family of biodegradable polymers called polyketals and their derivatives may improve treatment for such inflammatory illnesses as acute lung injury, acute liver failure and inflammatory bowel disease by delivering drugs, proteins and snips of ribonucleic acid to disease locations in the body.
Source: Science News

Photo: asylumresearch.com

There was a time no so long ago, when people would throw food scraps, peelings and the like into the compos heap in the back corner of their garden. The rest of the household rubbish went into the dustbin in plastic sacks. Since those days, things have changed. Now you can feed the compost heap with the plastic sacks too. British company Symphony Environmental is producing fully degradable bin bags, carrier bags and other plastic bags from polyethylene, using new additive technology to reduce the plastic to carbon dioxide and water in just a few weeks.

Degradable Polyethylene
Symphony’s material is the first example of 100% degradable polyethylene. The plastic, known as SPITEK, has the same mechanical properties and processing characteristics as regular polyethylene and so can be used in the same way to make products. However, it has a special ingredient – up to 3% of a degradable compostable plastic (DCP) additive made under license from its developers EPI. This additive acts as a catalyst for the degradation of the polyethylene, kick starting the process when conditions dictate.

The Need for a Fully Degradable Plastic
The need for a fully degradable plastic is pressing. Millions of tonnes of plastic waste, including refuse sacks, carrier bags and packaging, are buried in landfill sites around the world each year. China generates about 16 million tonnes, India 4.5 million tonnes and the UK 1 million tonnes, of which more than 800,000 tonnes is waste polyethylene. Other disposal routes are possible for these materials, such as recycling and incineration, but as much of the waste plastic is mixed up with other materials in the domestic and industrial waste streams, separation is costly particularly for small items such as carrier bags.

Conventional Polyethylene
Conventional polyethylene products can take longer than 100 years to degrade, taking up valuable landfill space and potentially preventing the breakdown of biodegradable materials contained, say, in a refuse sack.

Effect on Landfill Sites
Symphony claims that its new plastic could effectively increase the capacity of landfill sites by as much as 20 to 30% by breaking down in a short time and allowing other materials to degrade.

Degradation Properties
The SPI-TEK material can be engineered to degrade in as little as 60 days or as long as 5 to 6 years, depending on the application. The level of the proprietary EPI DCP additive effectively determines the rate of degradation and the shelf life of products made from the polyethylene. Degradation is initiated by a number of factors – sunlight, heat and stress from pulling and tearing can all start the process, which then continues even if the material is in landfill or under water.

How the Degradation Process Works
The catalyst causes carbon-carbon bonds in the polyethylene backbone to be broken, reducing the molecular weight and durability of the material. Tests have shown a reduction in molecular weight from a quarter of a million to less than 4,000, at which point the material can be digested by microorganisms in the soil and water. The final products of the degradation process are simply carbon dioxide and water. The DCP additive is neither water soluble nor toxic, making the material safe for disposal in landfill sites such as the flushing bio-reactor systems that are widely used in the UK. These systems introduce pressurised water flows into the layers of waste material, feeding oxygen and microorganisms down to the degrading rubbish.
Source: azom.com
 

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