This is very promising with obvious bennies all around. https://phys.org/news/2019-06-group-plastic-products-jet-fuel.html As an aside - yet another American university research team led by a Chinese scientist. (course I have no idea of their citizenship). They seem to be rather prominent these days.
They can all be recycled, but not when all the different types of plastic are mixed together. Some plastics, like PVC and acrylic, can be more problematic and expensive to recycle because they tend to give off poisonous gases and can pose toxic environmental issues. (Safety issues greatly add to the expense, and then the flue gases have to go through further separation to avoid leaking out the toxic substances into the environment, which decreases energy efficiency) A process known as pyrolysis can be used to recycle different types of plastics together, but is much more energy intensive, less efficient, and more polluting, because the molecular structure has to be broken down further into more basic building blocks.
If people wanted to be very environmentally friendly, one idea would be to come up with one single type of molecular building block that could be slightly chemically/physically modified in some way so that it could take on different properties to replace all current common consumer products, but would still be able to all be easily recycled together, and converted back into those different type plastic forms with different properties.
It's easier. It has to do with the molecular weight. They developed a process that can be used to convert waste plastic into fuel, but most of the fuel resulting from that process is the molecular weight appropriate for jet fuel. Turning it into car fuel would require an additional process, adding additional expense and decreasing the overall energy efficiency of the process. It would just be more practical to use it for jet fuel.
If you read the story, you would note that unless they separate the product into jet fuel and diesel fuel, they would have to use it all for diesel fuel.
