Getting rid of plastic waste remains a Sisyphean task despite our efforts to tackle it by employing PET-eating bacteria and turning it into footwear, liquid fuel, and even the foundations for an entire village. The material that ends up being recovered and reused is just a drop in a non-stop growing mountain of garbage. But what if there was a way to create a super-durable alloy out of two of the biggest sources of packaging waste while using less oil at the same time?   Bringing this potential win-win scenario a step closer to reality is a team of scientists from Cornell University and the University of Minnesota, who recently announced the creation of a polymer additive that can create such an alloy out of polyethylene (PE) and polypropylene (PP). The idea, according to researcher Geoffrey Coates, a professor of chemistry and chemical biology at Cornell University, is two-fold: to make a better material from the world's most used polymers and also help recycle them more efficiently. Though PE and PP are individually tough as standalone plastics and have a similar hydrocarbon makeup, they are immiscible with one another. Common grades of the polymers become brittle and unusable when blended together, thus limiting what companies can do to recycle these materials. To get around this problem, the research team developed a multiblock copolymer that can weld common grades of commercial PE and isotactic polypropylene (iPP) together, depending on the molecular weights and architecture of the block copolymers, by creating molecular stitches between the two materials. This makes the resulting blend as tough as iPP and PE themselves. In their tests, the researchers welded together two strips of iPP and PE plastic using different multi-block polymers as adhesives, and then pulled them apart. In most cases, the polymers are easily separated due to their incompatibility, as was demonstrated when the researchers carried out the tests with di-block polymers. However, in the case of the tetrablock additive, the plastic strips held together so well that it ripped the polymer apart, a sign that it is "a very good material" to glue polyethylene and polypropylene together, says Coates. According to the researchers, what makes the results all the more encouraging is that they were able to create the alloy with just one percent of the additive, giving rise to the possibility that it could improve recycling and also lead to the creation of a whole new class of mechanically tough polymer blends. For Ernie Simpson, global vice-president of research and development at TerraCycle, the New Jersey-based company that specializes in upcycling consumer waste, what makes this a potential game changer is the cost savings it could bring to a company's bottom line compared to the current compatibilizers on the market. "If the claims are true that a one percent addition is as efficient at 10 percent of other compatibilizers, on a cost-basis, this would be a serious game changer," Simpson tells New Atlas. "It would essentially reduce the overall cost of modifying polyolefins and significantly increase the amount of polypropylene and polyethylene that gets recycled because the formulations can be made at a lower cost." Of course, this depends on factors such as the amount of compatibilizers being used and their original cost. Assuming this new material comes in at roughly the same cost and requires just one percent instead of 10, the savings would encourage people to make new formulations based on the tetrablock and use them in various applications, he points out.