Plastic is made from polymers, which may be synthetic, semi-synthetic, or biobased. Plastics’ main property is their plasticity, making it easy to mould, extrude, or press into solid objects of various shapes. The versatility of plastic derived from fossil fuels and its light weight, durability, flexibility, and cost-effectiveness have made it extensively used in all industries worldwide.
Extracting raw materials like crude oil, natural gas, and coal is the first step in making plastics. Then, through a refining process, it’s transformed into different petroleum products by being heated in a furnace. It is then sent to the distillation unit, where heavy crude oil separates into lighter components called fractions. One of these, naphtha, is the crucial compound that makes the majority of plastic. After refining, light olefin gases (gasoline) such as ethylene, propylene, and butylene (i.e., monomers) are converted into polymers through a polymerisation process. This process bonds the monomers into chains.
Thermoplastics and thermoset plastics are the two classes of polymers in plastics. The difference is how they are made and how they react to heat.
- Thermoplastics can be melted and reshaped multiple times. They’re like butter that melts when heated and solidifies when cooled. When heated, their polymer chains slide past each other, softening the material, and when cooled, they harden again. However, recycling often leads to a decrease in material quality. Common examples include polyethene (PE) and polypropylene (PP), which we use to make textiles, packaging, and other consumer goods.
- Thermoset plastics contain polymers that form irreversible chemical bonds and cannot be recycled. We can compare them with eggs; once cooked, they can’t return to their liquid state. The cross-linked polymer structure prevents remelting or reshaping after becoming hard. This type of plastic is durable but nearly impossible to recycle. Thermosets are used in products like adhesives, coatings, and electrical insulators. Their strong, rigid structure makes them ideal for high-heat and high-stress applications; however, their limited recyclability contributes to environmental issues.
Recently, there has been a growing awareness of plastic pollution, plastic waste’s environmental and health impacts, particularly in oceans and ecosystems, as well as microplastics and the risk to human health.
The challenges in addressing plastic pollution are rooted in the plastic and oil industry and how they design the material, the inefficiency of recycling processes, and inadequate infrastructure. Most recycling leads to downcycling, reducing material quality, while rising plastic production outpaces recycling efforts. Right now, so much of the plastic produced is not even recyclable, nor was it designed to be recycled.
Addressing these issues involves strengthening recycling systems and regulations while reducing plastic production to minimize waste and environmental harm. Products should be designed for recyclability and produced with high-quality standards when using virgin materials.
A recent industrial method involves creating bio-based materials from renewable sources, such as byproducts of cane sugar, corn or cotton, as an alternative to conventional plastics. While some bio-based plastics are designed to be compostable, questions remain about their ability to break down without causing harm to nature or animals. Scientists are looking for alternatives that can break down faster. Still, studies show that even bioplastics(PLA-Polylactic Acid) have a negative effect on biological life and should not be marketed as an environmentally friendly alternative.
Sources
ReThink – Microplastics-ocean
Wikipedia – Plastic 
Youtube – FuseSchool – Problems with Plastics – Environmental Chemistry
Miljo-Utveckling.se – Researchers: Paper cups as toxic as plastic cups
Miljo-Utveckling.se – Bio-degradable Plastics
December 2024, RETHINK
