Plastics are substances formed by converting molecules called monomers, which are formed by some organic and inorganic elements in nature, into polymers with a more complex structure under a certain temperature and pressure, with the help of a catalyst. The meaning of plastic as a word is “soft” and “easy to shape”.
The word polymer, which is frequently used when describing plastic, means “consisting of many parts”. Polymers consist of long-chain molecules formed by chemically splicing and joining short-chain molecules.
Because plastic is cheap and easy to produce, durable and easily formable:
in household and kitchen utensils,
in sachets, bags and food/beverage packaging,
in the aircraft, train, automobile and ship industries,
in the construction and building industry,
in electrical and electronic applications,
in clothing and textile products,
in energy production,
in medical and other medical products,
in the military industry and law enforcement products,
in sports equipment,
in hygiene products,
in art and music products
in baby products,
in 3D printing technology
and appears in many different products.
Without plastics, modern medicine simply wouldn’t be as we know it. Plastic is a vital part of almost everything that happens in hospitals, operating rooms and doctor’s offices today. However, there is an increasingly widespread concern that although plastics can help make us healthier, the abundance of plastic in our lives is also making us sick. Plastics that provide us with medical miracles can also poison us slowly and almost certainly.
People have been wary of plastics since their earliest invention. In 1869, after John Wesley Hyatt invented the first synthetic polymer, celluloid, consumers bought brushes, combs, shirt collars, pool balls, and toothbrushes made from this new material. As celluloid grows in popularity, so do concerns about its flammability. Dramatic stories, perhaps fueled by a natural human distrust of new, unfamiliar things, fueled celluloid’s reputation as a dangerous explosive, making it harder to tell the truth from fiction.
While the danger stories are often exaggerated, some plastics have actually proven harmful. In 1959, dry cleaners began wrapping laundry in thin, sticky plastic bags. A storm of terrible news soon followed: In just a few months, 80 young children had drowned while playing with bags. Cries to ban bags led the plastics manufacturing industry to launch a national education campaign on how to dispose of bags correctly and change manufacturing specifications to make bags less hazardous.
This plastic quickly proved its value to human health. In the 1940s, Harvard Medical School professor Carl Walter used plastic in the blood collection revolution. Traditional glass and rubber systems for blood collection and storage were heavy, fragile, and difficult to sterilize between uses. Walter experimented with plasticized polyvinyl chloride (PVC), a polymer made flexible by the addition of DEHP, a phthalate. Plasticized PVC was durable, inexpensive, lightweight and disposable, and its use greatly increased the sterility and safety of blood collection and storage. It also allowed doctors to separate blood into red blood cells, plasma, and platelets, thus using a single unit of blood to treat three people. This system quickly became a success. After being tried and proven by military doctors in the Korean War, PVC blood storage became the norm in American hospitals in the 1960s. Plastic has quickly replaced glass and metal in other medical equipment as well, where its versatility has solved countless problems arising from other materials.
Although PVC has made life-saving medical advances, it has caused serious health problems. In 1974, four workers at BF Goodrich Company’s PVC plant died of the same rare liver cancer. One study involved exposure to chlorine gas added to PVC to impart strength, flexibility, and fire resistance to the plastic. The federal government took action to address the problem by enforcing strict regulations in worker safety conditions to prevent future exposures.
The crisis at the Goodrich plant has raised concerns about the safety of plastics and the additives used to manufacture them. The research suggested that what goes into plastic during the manufacturing process doesn’t always stay there. In 1969, Johns Hopkins University toxicologists Robert Rubin and Rudolph Jaeger found that DEHP leaches from plastic and into human tissues. A Washington Post article published in 1972 noted that phthalates such as DEHP were found in blood samples from people who were only exposed to plastic only through daily contact, stating that “people are just a little bit plastic now.”
The basic principle of toxicology is that almost any chemical can be toxic if too much is consumed. Even water, essential for all life, can be fatal if you drink too much. Paracelsus, the founder of 16th-century toxicology, put it succinctly: “The poison is in the dose.” But the chemicals that seep into the human body and the environment from plastic may be a different toxin. A renowned toxicology researcher, Theo Colburn, argues that when it comes to phthalates and other plastic additives, timing may be the most important, not the amount of dose. Colburn and other researchers say plastic additives can disrupt human endocrine or hormonal systems, and for children and infants, exposure can have a huge impact on development, even in small doses.
The plastics industry is reacting sharply to reports from researchers like Colburn, arguing that no studies have conclusively proven plastics to be unsafe. Industry, linking plastic to endocrine disruption, questioning research methods and results, and stating that endocrine disruption in the presence of plastic does not prove that plastics cause endocrine disruption.
There are many reasons why plastic is so widely used. If we summarize why plastic is preferred so much industrially:
Plastic; cheap, light and durable. No other substance combines these properties.
Plastic; It is used in the construction of buildings, bridges and is preferred due to its durability and cheapness.
It is used in the automobile industry, allowing us to get on safer, cheaper and more performance vehicles.
It is the easiest solution in most cases to preserve food and chemicals.
It appears as sports equipment.
In the field of health, it is one of the materials used in hospitals.
The computers and phones we use are made of plastic.
Thanks to the plastic that does not conduct electricity, we can safely use electrical appliances.
The most common types of plastic used in these areas are as follows:
Polyethylene terephthalate (PETE or PET)
Polyvinyl Chloride (PVC)
Polylactic Acid (PLA)
Acetal or Polyoxymethylene (POM)
Acrylonitrile Butadiene Styrene (ABS)
1. Appearance of Plastics
Transparent, colored, etc. in the market. There are many plastic models available. To achieve these different properties, appropriate pigments are added to the plastic material manufacturing process. That is, they will give the structure a beautiful appearance and make it attractive.
2. Chemical Resistance of Plastics
Plastics offer great resistance to chemicals and solvents. The chemical composition of plastics during manufacture will decide the degree of chemical resistance. Most commercially available plastics offer great corrosion resistance. Therefore, pipes carrying water, etc. in some cases corrosive metals are replaced by plastic.
3. Dimensional Stability
Thermo-plastic type plastics can be easily reshaped and reused. But in the case of thermosetting type plastics, it is not possible to reshape or reshape the material.
4. Ductility of Plastics
The ductile nature of plastic is very low. When tensile stress acts on the plastic part, they can fail without any prior indication.
5. Durability of Plastics
Plastics with sufficient surface hardness have good durability. Sometimes plastics can be affected by termites and rodents, especially in the thermoplastic species, but it is not a serious problem as the plastic has no nutritional value.
6. Electrical Insulation
Plastics are good electrical insulators. For this reason, they are used as linings for electrical cables and electronic instruments.
Plastic can be given any finishing tool. During production, mass production of plastic particles with a homogeneous surface finish is carried out by making technical control.
8. Fire Resistance
Temperature or fire resistance for plastic varieties varies considerably depending on the construction. Plastics made from cellulose acetate are burned slowly. Plastics produced with PVC do not catch fire easily. Plastics made from phenol formaldehyde and urea formaldehyde are refractory materials.
Plastic materials are very easy to fix. We can bolt, drill or glue to fix the position of the plastic material.
Plastics made of cellulosic materials are affected by the presence of moisture. Plastics made from poly vinyl chloride (PVC pipes) offer great resistance to moisture.
Caring for plastics is very simple. Because any surface finishing coat, paint etc. They don’t need it.
12. Melting Point
Generally, the melting point of plastics is very low. Some plastics can only melt at 50oC. Therefore, they cannot be used in high temperature positions. Thermo-setting plastics have a higher melting point than thermoplastic type plastics. However, thermosetting types cannot be used for recycling. In order to increase the heat resistance of plastics, glass fiber reinforcement is provided in its structure.
13. Optical Property
There are so many types of plastic. Some plastics are transparent, allowing light to be in its original direction, and some are translucent, but translucent, allowing light but changing the direction of light rays.
14. Recycling of Plastics
Disposal of plastics into the environment causes serious pollution. However, it is not a serious problem due to its recycling feature. Plastic waste disposal through drainage pipes, fences, railings, carpets, benches, etc. We can easily use it to produce.
15. Sound Absorption
We can produce acoustic panels with saturation of phenolic resins. These acoustic boards are sound absorbers and provide sound insulation. This type of acoustic ceilings are generally used in theaters and seminar halls.
In practice, we can say that plastic is a strong material, but the ideal cross-section of the plastic useful for the structural component has not yet been designed. It generally increases the strength of the fibrous material by reinforcing the plastic. If the strength-to-weight ratio of plastic is the same as metals, we cannot prefer plastics for various reasons such as heavy cost, creep failure, weak hardness and temperature sensitivity.
17. Thermal Property
The thermal conductivity of plastics is very low and is similar to wood. Therefore, foamed and expanded plastics are used as thermal insulators.
18. Weather Resistance
Most plastics are weather resistant, except for some limited varieties. However, plastics are those that are severely affected by ultraviolet rays and become brittle when exposed to sunlight. To prevent this, plastics are combined with fillers and pigments that help absorb or reflect UV rays onto the surface.
19. Plastic Weight
Plastics have low specific gravity and usually range from 1.3 to 1.4. Therefore, they are lightweight and can be easily transported in large quantities to any location.