See more. Top 3 Takeaways 1. Want to do more? The ART of Advanced Recycling Advanced Recycling Technologies ARTs are essential to ensuring that plastics stay out of the environment, while also creating new products and economic growth opportunities that benefit society. Learn More. The Power of Plastic Packaging in Transportation Plastic packaging protects products in transit and with a lower environmental impact than alternatives. Plastics are simply chains of like molecules linked together.
These chains are called polymers. Polymers often are made of carbon and hydrogen and sometimes oxygen, nitrogen, sulfur, chlorine, fluorine, phosphorous, or silicon. Although there are many polymers, plastics in general are lightweight with significant degrees of strength. Plastics can be molded, extruded, cast and blown into seemingly limitless shapes and films or foams or even drawn into fibers for textiles.
In this way, petroleum is decomposed into petroleum gas, gasoline, paraffin kerosene , naphtha, light oil, heavy oil, etc. After the distillation step, the obtained long chain hydrocarbons are converted into hydrocarbons that can then be turned into many important chemicals which we use for the preparation of a wide range of products applicable from plastic to pharmaceuticals.
Steam cracKing uses high temperature and pressure to break the hydrocarbons long chains without a catalyst, whilst catalytic cracking adds a catalyst which allows the process to occur at lower temperatures and pressures. The raw material used by the petrochemical industry is mainly naphtha and natural gas from oil refining operation in the petrochemical feedstock. Steam cracking uses the feedstocks from hydrocarbons mixture from various fractions such as reactant gases ethane, propane or butane from natural gas , or liquids naphtha or gas oil Figure 4.
Naphtha is a mixture of C 5 to C 10 hydrocarbons obtained from the distillation of crude oil. For example, decane hydrocarbon is cracked down into products such as propylene and heptane where the former is then used to make poly propylene Figure 5. Figure 5. Representation of Cracking of decane to convert into propylene and heptane. Raw materials molecules are converted into monomers such as ethylene, propylene, and butene and others.
All these monomers comprise double bonds so that the carbon atoms can subsequently react to form polymers. Polymerisation - hydrocarbon monomers are then linked together by chemical polymerisation mechanism to produce polymers. Polymerisation process generates thick, viscous substances as resins, which are employed to make a plastic product. If we look at a case of ethylene monomer here; ethylene is a gaseous hydrocarbon.
When it is subjected to heat, pressure and a certain catalyst, it joins together into long, repeating carbon chains. These joined molecules polymer is a plastic resin known as polyethylene PE. Production of PE based plastic —poly ethylene is processed in a factory to make plastic pellets. The pellets are poured into a reactor, melted into a thick liquid to cast into a mould. The liquid cools down to harden into a solid plastic and produce a finished product.
Processing of polymer also includes the addition of plasticizers, dyes and flame-retardant chemicals. Synthetic plastic is made by a reaction known as polymerisation, which can be performed in two different ways:. Addition polymerisation : Synthesis includes adding together monomers in a long chain.
One monomer connects to the next and so on, when a catalyst is introduced, in a process known as chain growth polymers, adding one monomer unit at a time.
Some addition polymerisation reactions are considered to create no side-products and the reaction can be performed in the vapour phase i. Examples: polyethylene, polypropylene, polyvinyl chloride and polystyrene. Condensation polymerisation : In this case, two monomers combine to form a dimer two units by releasing a byproduct. Dimers can then join to form tetramers four units and so on.
These byproducts are necessary to be removed for the success of the reaction. The most common byproduct is water, which is treated and disposed of easily. Byproducts can also be valuable raw materials that are recycled back into the feedstream. Plastic is often created from naphtha.
Ethylene and propylene, for example, are the main raw material for oil-based plastic coming from Naphtha. There are different types of naphtha. It is a term used to describe a group of volatile mixtures of liquid hydrocarbons, obtained by the distillation of crude oil. It is a mixture of C 5 to C 10 hydrocarbons. These are olefins and aromatics. Among the olefins, there is C 2 ethylene , C 3 propylene , C 4 butane and butadiene. The aromatics consist of benzene, toluene and xylene.
These small molecules are linked together by into long molecular chains called polymers. When a polymer comes out of the chemical factory they it is still not in the form of plastic — they are in the form of granules or powders or liquids.
Before they can become an everyday use plastic they need to undergo a series of transformations. They are kneaded, heated, melted, and cooled into objects of various shape, size colour with precise properties according to the processing tubes.
For instance, for polymerisation of ethylene into polyethylene PE , initiators are added to start the chain reaction, only after the formation of PE, it is sent for processing by addition of some chemicals antioxidants and stabilisers. After which an extruder convertsn PE into strings, thereafter grinders convert it into PE pellets. According to a study , more than half of non-fiber plastic, which excludes synthetic fabrics like polyester and nylon, comes from plastic packaging alone, much of which is for single-use items.
Single-use plastics are a glaring example of the problems with throwaway culture. Instead of investing in quality goods that will last, we often prioritize convenience over durability and consideration of long-term impacts. Our reliance on these plastics means we are accumulating waste at a staggering rate. We produce million tons of plastic each year worldwide, half of which is for single-use items. Reducing plastic use is the most effective means of avoiding this waste and the impacts linked to plastic production and use.
Carrying reusable bags and bottles is one great way to avoid single-use plastics in our day-to-day lives; more on preventing plastic waste can be found below. Recycling more plastic, more frequently, reduces its footprint. Polyethylene terephthalate, one of the most commonly recycled plastics and the material that makes up most water and soda bottles, can be turned into everything from polyester fabric to automotive parts.
Instead it ends up in landfills or in the environment. Single-use plastics in particular—especially small items like straws, bags, and cutlery—are traditionally hard to recycle because they fall into the crevices of recycling machinery and therefore are often not accepted by recycling centers.
Over time, sun and heat slowly turn plastics into smaller and smaller pieces until they eventually become what are known as microplastics. These microscopic plastic fragments, no more than 5 millimeters long, are hard to detect—and are just about everywhere. Some microplastics are even small by design, like the microbeads used in facial scrubs or the microfibers in polyester clothing.
They end up in the water, eaten by wildlife, and inside our bodies. Exposure to microplastics, as well as the chemicals that are added to plastics during processing, harm our health. Many of the chemicals in plastics are known endocrine disruptors , and research has suggested that human exposure could cause health impacts including hormonal imbalances , reproductive problems like infertility, and even cancer.
The phthalate DEHP, as just one example from dozens, is often added to plastic goods like shower curtains and garden hoses to make them more flexible—but was also found to be a probable human carcinogen by the U. Environmental Protection Agency. Although single-use plastic pollution accumulates most visibly on our streets, in fact our water suffers even more.
Litter can be the first stage in a waste stream that enters waterways as plastics tossed on the street are washed away by rain or travel via storm drains into rivers and streams. In researchers from the University of Georgia estimated that between 4.
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