{"id":9620,"date":"2026-03-25T11:25:16","date_gmt":"2026-03-25T10:25:16","guid":{"rendered":"https:\/\/kluthe.com\/magazin\/?p=9620"},"modified":"2026-03-26T10:21:41","modified_gmt":"2026-03-26T09:21:41","slug":"plastic-recycling-in-chemistry","status":"publish","type":"post","link":"https:\/\/kluthe.com\/magazin\/en\/plastic-recycling-in-chemistry\/","title":{"rendered":"Plastic Recycling in Chemistry"},"content":{"rendered":"

\u00ab What Methods Are Used? \u00bb<\/h2>\n

Plastics are widely used as packaging materials, insulators, components in various machines and devices, and as coating agents. Unfortunately, their widespread use has led to increasing environmental concerns as they are now frequently found in the environment. \u00a0Recycling offers a potential solution\u2014but not all chemical recycling methods are equally environmentally friendly. The following provides an overview of chemical processes used to recover value from plastic waste.<\/strong><\/p>\n

Type and Composition of Plastic Waste<\/h2>\n

The choice of recycling method depends on the physical characteristics of the material and the degree of contamination or \u00a0interaction with other substances. Plastics fall into three main categories: thermoplastics, thermosets, and elastomers. Thermoplastics, such as PVC, polyethylene, and polypropylene, soften when heated and can be reshaped and reused once cooled.<\/p>\n

<\/i>\n\t\t\t\n

Thermosets, such as phenolic resins, epoxy resins, and vinyl ester resins, are heat-resistant and decompose when exposed to very high temperatures. If oxygen is present, combustion may occur.<\/p>\n\n\t\t\t<\/div><\/div>\n

These materials can only be recycled by chemically breaking down the molecular bonds in their polymer chains. This process known as solvolysis. Elastomers, which behave like rubber, also decompose at high temperatures. However, they can still be recycled in shredded form, for example, as filler in bitumen applications.<\/p>\n

\"Bitumen
\u00a9 Vladimir Bikhovskiy \u2013 stock.adobe.com<\/figcaption><\/figure>\n

The degree of mixing significantly affects the recycling process. Homogeneous plastic waste is easiest to recycle. When different types of plastics are mixed, combined with other materials, or contaminated, extensive sorting and separation steps are often necessary\u2014especially in the case of collected packaging waste, composites, and coated components. Surface coatings, commonly used to enhance the performance of plastic parts, often interfere with recycling and must be removed in advance.<\/p>\n

Types of Recovery Processes<\/h2>\n

There are three main categories of recovery for plastics within sustainable chemical practices<\/a>: mechanical recycling, chemical (feedstock) recycling, and energy recovery.<\/p>\n

    \n
  • Mechanical recycling preserves the base material. The plastic is cleaned and reprocessed\u2014using dry, wet, or solvent-based techniques\u2014so that it can be reused. These methods are primarily physical and mechanical.<\/li>\n
  • Chemical recycling (also called feedstock recycling) uses chemical reactions to break down plastics into raw materials, which can then be used to make new products.<\/li>\n
  • Energy recovery is not considered a recycling method in the strict sense of chemistry. In this process, plastic waste is incinerated to generate energy.<\/li>\n<\/ul>\n

    \"Hot<\/a>Chemical Recycling Methods<\/h2>\n

    The most common chemical recycling methods are liquefaction (oil recovery), solvolysis, gasification, and pyrolysis. These often require pre-treatment steps to remove contaminants, such as separating multi-layer materials (e.g., beverage cartons, coated films) or stripping surface coatings. Eco-friendly paint stripping agents<\/a> are available for these tasks.<\/p>\n

    Liquefaction (Oil Recovery)<\/h3>\n

    In this process, plastics are converted into oily substances through thermal or catalytic reactions, which requires well-sorted plastic waste. The reaction typically occurs in stirred tank reactors at temperatures up to 750\u00b0F (400\u00b0C). As the plastic liquefies, gaseous by-products and wax-like residues are separated from the resulting oil.<\/p>\n

    After purification and distillation, the recovered oil can be used as diesel fuel or as a chemical feedstock.<\/p>\n

    Solvolysis<\/h3>\n

    Solvolysis breaks down the polymer chains in plastics using special solvents. The reaction may be aided by elevated temperatures and is primarily used for recycling thermosets. It yields the original building blocks of the plastic, which are then separated from the solvent.<\/p>\n

    <\/i>\n\t\t\tSolvolysis is primarily used for recycling thermosetting plastics. What remains are the basic building blocks of the plastic, which must be separated from the solvent.\n\t\t\t<\/div><\/div>\n

    The solvents are usually reused in a closed-loop system. Depending on the input material, valuable raw components can be recovered from the decomposed polymers.<\/p>\n

    Gasification<\/h3>\n

    Gasification is conducted at temperatures of up to 2,900\u00b0F (1,600\u00b0C) and pressures up to 2,175 psi (150 bar) with limited oxygen supply. This oxygen does not support combustion but facilitates the reaction between carbon and oxygen. The process produces a synthetic gas (syngas) composed of carbon monoxide and hydrogen. Before further use, impurities must be removed. Syngas serves as a raw material for a wide range of chemical products, including GTL (gas-to-liquid) oil<\/a>, which is used in surface treatment applications.<\/p>\n