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In the news today, Braskem Announces a Green Polypropylene Plant: the largest thermoplastic resin producer in the Americas will build the world's first manufacturing plant to produce "green propylene", a form of polypropylene made from renewable resources like sugar cane.  From their press-release: "The green polypropylene will have the same technical, processability and performance properties as polypropylene made using petroleum."

How is that?

One of the most well-known and often-discussed criticisms of bioplastics (for example, PLA) is that the properties of the final product do not quite match up with those of traditional plastics: it's not as strong, or not as heat-resistant, until you mix it in with other (usually non-green) chemicals and additives and binders.  At a fundamental level, the chemical structure of biopolymers is different from the chemical structure of artificial polymers... and so their resulting properties are different.

Here is the source of the success of "green polypropylene":

The chemical structure of "green polypropylene" is NOT different from the chemical structure of traditional, synthetic oil-based plastics.  There is not a single atom's worth of difference in the chemical structure.

The only difference is in how the polymer was created: in traditional plastics, the molecule is "built" from a process that starts with petroleum, in "green polypropylene" the molecule is "built" from a process that starts with sugar cane.  Once that molecule has been created, though, it is identical in every way to traditional plastics. 

To quote from the article in the most recent issue of bioplastics magazine: "Biobased polyethylene (and, once available, polypropylene) are NOT biodegradable. On the contrary, biobased PE and PP do not at all differ from petroleum based polyolefins. They have the same chemical structure and can be polymerized in the same way The same grades (film, injection, blow moulding, etc) can be created, and so on. The only difference is in the origin of the carbon.  Biobased polyolefins consist of renewable carbon."

Is that good or bad?

On the good side:

• It can be processed by existing plastics processing plants, so you don't have to build special new ones.
• It has the good properties of traditional plastics, like strength and heat and water resistence
• Creating it does not rely on oil, an unsafe and scarce non-renewable resource
• It can be safely recycled along with traditional plastics

On the bad side:

• Just like traditional plastic, it is not biodegradable

At first glance, of course, it seems like the good outweighs the bad.  When you look at the "two dimensions of green" -- renewability and degradability -- green polypropylene succeeds at one and fails at the other.  Isn't that a step in the right direction?  Isn't it a good thing, overall, to pursue every avenue for making plastics more environmentally friendly, even those that aren't environmentally "perfect"?  (We so often hear slogans these days like "pursue every option" or "don't let the perfect become the enemy of the good" and so on.)

I'm not saying I disagree. However, I think it is worthwhile to at least understand and think about the arguments from the other side.  Consider these questions:

What about the tonnes and tonnes of waste building up from discarded plastic?  Won't this simply continue to contribute to that problem?  Even though the carbon comes from renewable resources, once it's put into the "green propylene" it is trapped and will not be returned to the biosphere, because the product doesn't biodegrade.  Doesn't that do even more damage to the environment, by trapping what once was "free" carbon into these plastic products?

Some people will argue that green polypropylene is a "first step" technology, a way that we can be "more green right now" while we wait for the technology on biodegradable bioplastics to improve.  But if all of our industry starts getting geared up to this solution, will it simply delay our progress with plastics that are both based on renewable resources and biodegradable?

What do you think?

Today's big news:

SunChips not-so-quietly buries its noisy compostable bags
SunChips Sacks Its Line of Noisy Biodegradable Bags
Frito-Lay sends noisy, 'green' SunChips bag to the dump
Is Noise Really Why SunChips Should Ditch Bioplastic Packaging?

Here are the facts:

• 18 months ago Frito-Lay launched a biodegradable SunChips bag made from plant material that was billed as 100% compostable 
• Many people complained that the bags were too noisy, and specifically much noisier than the original packaging
• SunChips sales have declined more than 11% over the past 52 weeks, as reported by SymphonyIRI Group, the market research specialist.
• SunChips presumably makes the link: sales are down because people don't like the new bags
• SunChips decides to pull the new bags from production, while still looking for a "quieter" version of a compostable bag.

I'm sorry, but am I the only person who thinks that the data (points 1 - 3) do not support the conclusion (point 4)?

We live in an age where obsessed whiners can shout very loudly.  Facebook pages take no effort to create and even less effort to "like".  And the continual thrill-seeking media is anxious to report the funny (or thrilling, or stupid, or shocking) story that will pull viewers.  So the fact that some whiny people complained about noisy bags, some bored people thought it was funny and so "liked" a facebook page, and hystrionic media reported it as if it were news, suddenly leads some media consultant somewhere to conclude that the noisey bags actually drove consumer behavior. 

In other words: the bags get the blame for the 11% decrease in sales.

Is that a logical conclusion?

Let's be scientists for a moment. What is an alternative hypothesis? What other things do we know about our society, our economy, and our world that could possibly explain a decrease in (of all things) "SunChips" sales?

In a world where every day the headline is about unemployment, foreclosures, and debt, let's imagine that maybe people are spending less on expensive snack foods.  Let's put forward the hypothesis that when people are broke and hurting for money, they will want to spend less on food that has absolutely no nutritional value.

Now, with that hypothesis in mind, let's do a comparison of the price per ounce of some common snack foods:

The only snack food on the list that is more expensive per ounce than SunChips is Funyuns. (I wonder how their sales are doing?)

I'm sorry, SunChips, but I think we have a simpler explanation for why your sales might be declining in the last year.  And it's not your bags.

In the words of an oft-quoted politician: it's the economy, stupid.