Plastics have become an integral part of our daily lives, but it's important to delve into what exactly constitutes plastic and how it's manufactured.
Before plastic became so widespread, it underwent a significant transformation from being a natural substance to being synthetically and extensively produced. Some of the earliest instances of plastic usage date back 3,500 years when the Olmecs of Mexico utilized naturally occurring plastics, like sap from gum trees, to craft rubber balls. During the mid-19th and 20th centuries, synthetic plastics like celluloid and Bakelite made their debut and enjoyed decades of use.
On a molecular level, plastics are composed of polymers, which are long, flexible chains of chemical compounds. This structure makes plastics highly moldable and shapeable, especially when subjected to heat and pressure. Unlike the natural rubber used by the Olmecs, most modern plastics are man-made and derived from fossil fuels, primarily crude oil and natural gas. These sources provide a cost-effective alternative to plant-based plastics.
The initial step in plastic production involves extracting crude oil and natural gas from the ground. These fossil fuels are then processed in refineries to create various products, including the foundational components of plastic: ethane from crude oil and propane from natural gas. Ethane and propane are subsequently sent to a cracker plant where they are broken down into smaller molecules. Ethane yields ethylene, while propane becomes propylene. A catalyst is introduced to link these molecules, forming polymers known as resins. This resin structure allows for the malleability and moldability of plastics, particularly under heat and pressure. Polymerization transforms ethylene into polyethylene and propylene into polypropylene. These resins are melted, cooled, and chopped into pre-production plastic pellets, referred to as nurdles. Nurdles are then shipped to manufacturers who utilize heat to shape them into various types of plastic products, many of which feature resin identification codes indicating the chemicals used in their production.
Due to its versatility, global plastic production has doubled approximately every decade. Since 1950, an estimated 9.2 billion tons of plastic have been produced, equivalent to nearly 1,600 Great Pyramids of Giza in weight. Unfortunately, much of this plastic ends up as waste, with single-use plastics such as straws, grocery bags, and packaging products being particularly problematic. They are often not recycled and constitute roughly 40% of all plastic waste, leading to environmental damage and endangering wildlife.
To combat plastic pollution, it is crucial to reduce our reliance on single-use plastics and opt for reusable alternatives in our daily lives. Each individual's choice can significantly contribute to decreasing plastic waste. Additionally, efforts are underway to find solutions for existing plastics, including the discovery of organisms capable of breaking down plastic materials. Some microorganisms can reduce the time it takes for plastics to degrade from hundreds of years to just a few days.
In terms of plastic production, some manufacturers are turning back to plant-based ingredients. Biodegradable bioplastics, for instance, are as durable as synthetic plastics but originate from renewable resources and can naturally biodegrade. Even the rubber tree, used by the Olmecs, is once again being tapped for plastic production. Its latex is now used to create various products, such as natural latex rubber gloves, tires, and mattresses, as part of a global initiative for natural and sustainable plastic sourcing.
Plastics are ubiquitous, but by understanding their chemical composition and our usage patterns, we can harness their versatility while being mindful of their impact on our planet. Taking a pledge to reduce single-use plastics is a meaningful step in this direction,and that's why it's important to understand the subject we use.