EPI Shine a Light on Programmable Plastics

Plastics have revolutionised packaging. Their light weight, strength and durability, processability and low cost make them the material of choice for a host of applications. In food applications they prevent spoilage and make distant markets accessible. They do, however, have one troublesome property when destined for single use applications: they persist for a long time when discarded.

Billions of research dollars have been spent over the past 20 years to limit the life of plastics. Two systems have been discovered. One of these produces brand new plastics that degrade quickly, generally at the expense of other desirable properties, including cost.

The second, pioneered by Environmental Technologies Inc (EPI), focuses on using additives to manage the well-known reaction of common conventional plastics with oxygen in the air. This reaction degrades these plastics into smaller molecules that are amenable to biodegradation

EPI has spent the past 12 years developing additives, named TDPA, for a wide variety of PE, PP and PS packaging applications – flexible films (single and multi-layer) and rigid containers. These additives limit the life of the plastic packaging when discarded without compromising the other properties of the original plastic. Products using these additives have a useful and defined shelf life prior to use and a lifetime in their application that allows for re-use.

RAPID POST-DISPOSAL DEGRADATION

The EPI additives accelerate the degradation of the plastic in a very controlled manner, such that it occurs only when it is exposed to conditions of disposal – heat, ultraviolet sunlight and/or mechanical stress in storage (not in storage or normal use). During the initial ‘degradation phase’, the additive fragments the plastic into smaller and smaller pieces, which ultimately in the presence of oxygen become biodegradable (if the plastic is polyethylene). The cost of this property to the user is 5–20 per cent over the cost of the untreated plastic.

Some other facts about EPI modified plastics:

• Products can be ‘programmed’ to degrade at different rates; typically disintegrating within about six months to two years with concurrent biodegradation.
• Products can be recycled in existing recycle streams into both degradable and non-degradable products. This is possible because the degradation reaction occurs even in conventional plastics, albeit very slowly, and management of this reaction is important to recyclers.
• Oxo-biodegradable products can be and are reused, like the same products made from conventional products.

Finally, and most importantly, this technology has been shown to be safe. The chemical catalyst used is commonly an oxidation compound. This is a micronutrient essential for life. It is added as a fertilizer to deficient soils and fed in salt licks to ruminant animals. Several studies have shown that composts made using oxo-biodegradable plastic bags are not eco-toxic and products using the technology may be used safely as food contact material.