Switchable Catalysis for Block Copolymer Compatibilization of Plastic Waste

塑料对环境既是朋友，也是敌人。虽然塑料污染构成了严重威胁，但作为太阳能电池、风力涡轮机叶片、充电电池和轻型电动汽车的关键部件，塑料也为绿色革命提供了动力。塑料是减少我们对化石燃料的依赖和二氧化碳排放的核心，因为它们被用于建筑绝缘和飞机的轻质部件。它们还通过延长保质期和减少食物浪费来促进粮食安全。目前的塑料生产和报废管理系统是不可持续的，迫切需要用可再生资源制造塑料。塑料垃圾提供了一种丰富而有吸引力的替代原料，但在2015年前生产的所有塑料中，约有60%被丢弃，目前只有10%的塑料被回收利用。开发将塑料垃圾升级为比原来更高质量或价值的产品的方法是一个有吸引力的目标，因为使回收行业现代化有可能使废物定价、创造就业机会和创造经济收入。最近对可持续塑料的推动导致了它们的市场快速增长，当它们进入并污染传统的回收流时，这可能是一个问题。回收导致材料性能变差的原因之一是，当两种不同的塑料被回收在一起时，它们不能很好地混合；这就像试图将油和水混合。这在两种塑料之间的界面上造成了紧张，即使是“错误的”塑料造成的少量污染也会污染并破坏一整批回收。这一挑战可以通过使用一种与两种塑料(即“水”和“油”)相互作用的分子来克服，通过充当分子“钉”在界面上连接两种塑料，从而创造出更坚固的材料。这些分子“钉书钉”需要两个不同的部分，一个与“油”相互作用，另一个与“水”相互作用。这个项目的目标是冒险的策略，使这些分子的“主食”，建立在我们的补充工作相容剂。将开发新的催化剂系统来制备“主链”的两种不同成分，该项目独特地专注于扩大分子开关的范围，这些分子开关可以在这两种不同的化学反应之间进行转换。目前尚不清楚在该项目中设计的制备分子“主链”的可切换策略，但这项新技术将通过使传统塑料与可持续塑料污染物混合，帮助未来防止回收流受到可持续塑料的污染。这是一个重要而及时的挑战，因为分离不同类型的塑料既昂贵又耗时，令人望而却步。如果成功，该项目将利用废弃的塑料垃圾作为原料，并将其转化为性能甚至可能比原始塑料更好的新材料，从而从废物中创造财富。

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.