Plastics INsight

Did you know 78 milshutterstock_77761861lion tons of plastic are used in a single year for packaging? This includes things like to-go containers and soda bottles. Only two percent of these items truly get reused and recycled, with the majority ending up in landfills. However, there is a reason these numbers are so startling, and it may have to do with polypropylene (PP) and polyethylene (PE) – something we have discussed before on our blog. We know, we know – you’re concerned about all of this, but please — don’t fear! Geoffrey Coates, Professor of Chemistry and Chemical Biology at Tisch University, and his team have discovered a solution that may combat the problem.

So, what do PP and PE have to do with this situation? According to Azo Materials they account for two-thirds of all plastics in the world, but the problem is they have different chemical structures, and currently cannot be repurposed together. That is until an efficient technology to meld the two into one comes along, and that has yet to happen in the 60 years PP and PE have been on the market.  

However, this roadblock could soon change with the development of a multiblock polymer by Coates’ and his team.  According to Azo Materials, this was achieved “by incorporating a tiny amount of their tetrablock (four-block) polymer – with alternating polypropylene and polyethylene segments – the resulting material has strength better than diblock (two-block) polymers they tested.”

During their research, the team welded two strips of plastic together using different multi-block polymers that acted as adhesives, and then mechanically separated them. According to Science Daily, “the welds made with diblock polymers failed relatively quickly, the weld made of the group’s tetrablock additive held so well that the plastic strips broke instead.”

This discovery may not only lead to more resourceful recycling, it could also change the world of polymers altogether. “If you could make a milk jug with 30 percent less material because it’s mechanically better, think of the sustainability of that,” Coates said. “You’re using less plastic, less oil, you have less stuff to recycle, you have a lighter product that uses less fossil fuel to move it.”

Coates’ research affirms that scientists have a lot left to discover in the polymer world. This discovery is yet another example of the amazing things happening in the world that could change the way we look at science.

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