Self-mending Plastic — recyclable?

The NY Times reports that University of Groningen-based researchers have developed a thermoset plastic that heals itself when heated. The idea of recycling thermoset resins — often used in printed circuit boards (PCBs) — sounds great; however, its usefulness needs to be considered with more depth:

a) Recyclables are at the mercy of practicality. If it is too difficult to source thermoset plastic scrap, then it doesn’t matter if the material is recyclable or not. (Note: this applies to popular use only; military use of these materials may differ, especially if the end-product is used in espionage.)

b) A plastic’s recyclability is also a function of it’s value. If, for instance, new thermoset resins are cheaper to buy virgin (new) than to source and recycle old end-products, then recycling stops making sense.

The researchers demonstrated that the material can be shredded, melted and remolded at least seven times with no loss of mechanical properties. Their discovery, they say, adds to scientific understanding of the nature of self-healing materials, and with more research may eventually lead to the full development of recyclable thermoset plastics.

c) Though the material can ostensibly be recycled, you have to take into account the recycling process. A plastic bag may be easy to recycle, but not when it’s been used to pick up feces. Likewise, thermoset plastic may become recyclable in the near future, but how easy is it? Circuit boards are full of non-plastic contaminants, for example; how do you go about purifying it in a way that keeps the process profitable (recyclers won’t touch scrap unless it’s profitable)?

There are many, many people developing all kinds of things that are newly recyclable or made from recycled material. Problems arise because these same people have little knowledge about how things are recycled; for example, plastic shopping bags made from recycled material are actually harder to recycle (because manufacturers mix in unknown materials and quantities when using recycled material). The bottom line, then, is that problems (yes, problems in general) need deeper insight. We’re always so concerned with coming up with new ideas, with making our knowledge wider. My contention is that we need to focus on depth, we need to make our ideas better.