Recycling means the reuse of secondary raw materials for different purposes associated with industry or with the maintenance of households. There are several methods of recycling, which include biological, thermal or energy decomposition. Given the huge amount of plastic waste, a great role is also played by chemical recycling. What is it and is it worth using? Let’s check.
Chemical recycling: definition
Let’s start from the basics and answer the following question: what is chemical recycling? Another name for the process is ‘feedstock recycling’, which is to say, the processing of raw materials in such a way that they can be reused for the production of packaging materials, bottles, etc. In most cases, chemical treatment is performed on plastics such as polypropylene, polyethylene, polyvinyl chloride, or polystyrene.
The raw materials produced by chemical recycling are wholesome. Thus it is not conventional downcycling, where materials lose some or all of their key properties. The chemical recycling of polymers is a technology that addresses the concept of Circular Economy (CO). The main goals of that strategy include:
- to reduce the amount of waste,
- to maximally use the potential of secondary raw materials and maintain them in circulation,
- to explore new applications of recycled final and semi-finished products.
What does the chemical recycling of packing materials involve?
Chemical recycling of waste polymer plastics is based mostly on depolymerisation processes. They enable the break-up of polymers into monomers: small molecules that can be further processed and reused. What exactly does chemical recycling consist of? One of its principal forms is the hydrolysis of plastics. It is a popular method of processing plastic waste where the key role is played by water, high pressure and temperature. Under these three effects, polymers decompose into tiny molecules used by the industry as semi-finished products.
Other methods of chemical recycling and depolymerisation include:
- glycolysis – a process where disintegrated PET plastics are exposed to high temperature, ethyl glycol and other chemical compounds to produce disintegrated polymer chains;
- alcoholysis (methanolysis) – under the influence of methyl alcohol, polymers delaminate to form a new raw material;
- aminolysis – a reaction between an amine (ammonia derivative) and polymers; as a result of aminolysis, plastics are disintegrated and can be reused in industrial processes.
How important is feedstock chemical recycling?
Feedstock (chemical) recycling was developed to address the continuously growing problem of plastics accumulating at landfills. This is because the measures taken within waste processing are still insufficient, and the quantity of plastic waste is growing dramatically fast. Each new method of recovering raw materials contributes to the improvement of the natural environment and helps reduce the carbon footprint left by humans.
The recycling of raw materials is also an interesting alternative to other forms of recycling such as material recycling of decomposed biodegradable materials. It makes it possible to process even such plastic wastes that are already partially decomposed. These mainly include rubbish, which massively contaminates the oceans, seas, lakes and rivers.
Chemical recycling of plastics: what are its benefits?
Why is the chemical recycling of polyurethanes worth a shot, and does it prove itself? It is definitely one of the most innovative technologies that allow keeping the plastics in circulation for as long as possible. With the feedstock recycling methods:
- we reduce the amount of waste,
- we do not have to produce materials from scratch or waste non-renewable resources,
- we need no additional area for storing plastic waste, and we can reduce the area of the existing landfills.
It should be emphasised that the chemical treatment can be used regardless of whether the waste is clean or contaminated with labels. The whole selection and pre-treatment processes are thus relatively short, which also entails lower energy consumption.
Read also: recycling.