Switchable Catalysis for Block Copolymer Compatibilization of Plastic Waste

点击翻译按钮获取中文摘要

Plastics are both a friend and foe to the environment. While plastic pollution poses a severe threat, plastics are also powering the green revolution as key components of solar cells, wind turbine blades, rechargeable batteries and lightweight electric cars. Plastics are central to reducing both our reliance on fossil fuels and CO2 emissions, through their use in building insulation and lightweight components of aeroplanes. They also contribute towards food security by extending shelf life and reducing food waste. Current plastic production and end-of-life management systems are unsustainable, and there is an urgent need to make plastics from renewable sources. Plastic waste offers a plentiful and attractive alternative feedstock, yet approximately 60% of all plastic produced before 2015 has been discarded, and only 10% of plastics are currently recycled. Developing methods of upcycling plastic waste into products of higher quality or value than the original is an attractive target, as modernising the recycling industry has the potential to valorise waste, create jobs and generate economic revenue.The recent drive for sustainable plastics has led to their rapid market growth, which can be problematic when they enter and contaminate conventional recycling streams. One of the reasons that recycling leads to poorer material properties is that when two different plastics are recycled together, they do not blend well; this is like trying to mix oil with water. This creates tension at the interface between the two plastics, and even a small amount of contamination with the "wrong" plastic can contaminate and ruin an entire batch of recycling. This challenge can be overcome by using a molecule that interacts with both types of plastic (i.e. the "water" and the "oil"), by acting as a molecular "staple" to connect the two plastics at the interface and thus create a stronger material. These molecular "staples" require two different sections, one that interacts with the "oil" and one that interacts with the "water". This project targets adventurous strategies to make these molecular "staples", building from our complementary work on compatibilizers. New catalyst systems will be developed to prepare the two distinct components of the "staple", and this project uniquely focuses on expanding the range of molecular switches that can convert between these two different chemical reactions. Switchable strategies to prepare the molecular "staples" designed in this project are currently unknown, but this new technology will help to futureproof recycling streams against contamination with sustainable plastics, by enabling conventional plastics to be blended with sustainable plastic contaminants. This is an important and timely challenge, as the separation of different types of plastics can be prohibitively expensive and time-consuming. If successful, this project will create wealth from waste, by using discarded plastic waste as a feedstock, and converting it into new materials that may even have better properties than the original plastics.