Stated by urethane manufacturers, today’s manufacturing community is becoming increasingly mindful of environmental impacts that arise during industrial processes. Industrial recycling, waste to energy systems, and emissions improvements are just part of a wide-ranging effort to minimize the impact of manufacturing on the environment.
Plastics have become a lightning rod for environmental commentators, as pictures go viral of various waste being found in far-flung areas of our planet.
Something that is not discussed in these discourses is the wide variety of plastics currently available, and how not all plastics degrade in the same fashion. Polyurethane has been unduly spotlighted in these negative conversations.
With limited resources available to the public on the matter, there is plenty of misinformation which we hope to clarify in this article.
Plastic Waste & A Start to Policy Changes
There have been some extremely shocking photos and stories that have come out in recent years with regard to plastic waste. Photos of all sizes of plastic waste being found in rivers, oceans, and forests have been circulated millions of times.
Some cities and countries have started enacting policy changes in a reactionary fashion after seeing the widespread outpouring of anger on social media.
Most plastics that have been illustrated in these campaigns are thermoplastics, which amount to well over 95% of all plastic found during ocean studies. Polyurethanes, however, account for less than 2% of all waste detected during ocean surveys.
In thermoplastics, no molecular bonds are holding the individual strands of polymer together. It’s held together by weak ionic forces, called Van Der Waal forces.
Think of these bonds as a ball of yarn, essentially being held together by the tangled ends of molecular chains. Simply put, the plastic will break down until the last thing left is individual strands. These are the “micro-plastics” which are commonly talked about in the news.
Finer than a human hair, sometimes even microscopic, this is the smallest the material will degrade to. Individual atoms will not separate from the polymer strand and will continue to linger in the environment for decades.
If you aren’t familiar with cast polyurethane it is considered a thermoset plastic. Do not confuse these with the thermoplastic we just discussed.
Polyurethane differs in that once the polymer has been reacted, the individual strands change on an atomic level and crosslink between each other. At these crosslinks, a new molecule is formed, entirely changing the properties of the material.
This molecular cross-linking is what makes polyurethane much more resilient in heavy-duty applications. Once the material has reached the end of its life, it can not be melted down and reformed.
Don’t think of this as a disadvantage since polyurethane materials will generally last longer than any thermoplastic equivalent. This minimizes the amount of polyurethane entering the waste stream right at the initial source.
There are multiple avenues that can be pursued when it comes to the recycling of polyurethane. Parts may be chemically reacted to turn back into their prepolymer state, however, the cost involved in this process can be quite steep.
When polyurethane breaks down in the environment, it will not break down into its individual polymer strands. Instead, individual bonds are broken down between molecules, releasing individual molecules into the environment.
These molecules are almost exclusively inert compounds that will not react or accumulate toxicity in natural environments.
Microbial degradation has become increasingly prevalent, especially in the area of fungi. Scientists have been able to find microorganisms that are well-suited for breaking downcast urethane products ecologically.
Polyurethane For the Win
The chemical makeup of polyurethane, combined with the increased lifetime of individual parts, means you can lower your commercial ecological footprint. Polyurethanes are non-toxic to the environment as they break down, and do not contain BPA or other chemicals which can interfere with endocrine systems.
The minimal effects on the environment will make this polymer even more desirable as we become increasingly environmentally conscious.