Types of Plastic – Almost every day we use plastic containers for various needs. However, did you know that plastic has various types and various dangers that can arise from it? In addition, plastic is a type of waste that is difficult to decompose because it takes tens or even thousands of years. Knowing and being familiar with the types of plastic can help us be wiser in using it according to the needs and the right capacity.
The term plastic itself includes synthetic or semi-synthetic polymerization products. Plastics are formed from the condensation of organics or the addition of polymers and may also be composed of other substances to improve the quality of the plastic. There are several natural polymers which include plastics. Plastics can be formed into films or synthetic fibers.
Plastics are designed with a wide variety of properties such as heat tolerance, toughness, resistance, etc. Combined with its adaptability, common composition and light weight, it is certain that plastic is used in almost all industrial fields. Plastic may also refer to any article which has the character of deforming or failing due to shear stress , see plasticity (physics) and ductile .
Plastic pellets or ore ready for further processing (injection molding, extrusion, etc.).
Plastics can be categorized in many ways, but the most common is the polymer ( vinyl chloride, polyethylene, acrylic, silicone, urethane , etc.). Plastics are polymers; long chains of atoms that bind to each other. These chains form many repeating molecular units or “monomers”.
Plastics generally consist of polymers of carbon alone or with oxygen, nitrogen, chlorine or sulfur (some of which are also composed of silicon). The plastic polymer is part of a chain in the main pathways that link the monomer units together. To set plastic properties the discrete molecular groups “hang” from the backbone (usually “hang” as part of the monomer before linking the monomers together to form the polymer chain). This setting by the “ pendant ” group has made plastics an integral part of 21st century life by improving the properties of the polymers.
The development of plastics extends from the use of natural materials (e.g., chewing gum, “ shellac ”) to chemically modified natural materials (e.g., natural rubber, “ nitrocellulose ”) and finally to man-made molecules (such as epoxy, polyvinyl chloride, and polyethylene ).
General History of Plastics
The history of plastic on earth was started by Alexander Parkes who first introduced plastic at an international exhibition in London, England in 1862. Parkes’ plastic invention called Parkesine was made from organic material from cellulose.
Parkes said that his invention has characteristics similar to rubber, but at a lower price. He also found that this Parkesine can be made transparent and can be made in various shapes. Unfortunately, these findings cannot be publicized because of the high cost of raw materials used.
Furthermore, the first man-made synthetic material was discovered by a chemist from New York named Leo Baekeland in 1907. He developed a liquid resin called Bakelite. This new material does not burn, does not melt, and does not melt in a vinegar solution. Thus, once this material was formed, it could not change. Bakelite can be added to a variety of other materials such as softwoods.
In 1933, Ralph Wiley, a lab worker at the chemical company Dow, accidentally discovered another type of plastic, namely Polyvinylidene Chloride or popularly known as Saran. Saran was first used for military equipment, but later it was discovered that the material was suitable for food packaging. Suggestions can be embedded in almost any piece of furniture such as bowls, plates, pans, and even in the suggestion layer itself. It is not surprising that suggestions are used to store food so that the freshness of the food is maintained.
Later that same year, two organic chemists named EW Fawcett and RO Gibson, who worked at the Imperial Chemical Industries Research Laboratory, discovered polyethylene . Their findings have a huge impact on the world. Due to its lightness and thinness, during World War II it was used as a coating for underwater cables and as insulation for radar.
In 1940, the use of polyethylene as an insulating material reduced the weight of the radar by 600 pounds, or about 270 kilograms. After the war ended, this plastic became increasingly popular and is currently used to make drink bottles, jerry cans, shopping bags or plastic bags, and containers for storing food.
Starting with bread wrappers, the mass use of plastic began in 1974 when giant US retail companies such as Sears and Jordan Marsh began using plastic bags as an alternative to paper bags. In 1977, plastic bags began to be used in grocery stores in the United States and Canada.
Plastic is a new material that has been widely developed and used since the 20th century. This object has grown tremendously in its use, from initially only a few hundred tons in the 1930s, increasing to 150 million tons/year in the 1990s and 220 million tons/year in 2005. Currently, the use of plastic materials in developing countries Western Europe reaches 60 kilograms/person/year, in the United States it reaches 80 kilograms/person/year, and in India only 2 kilograms/person/year.
General Types of Plastic
Plastic is an important component and a raw material for many items that we use everyday. However, have you ever paid attention to the logo on these plastic items? The logo is intended as an identity for the material used to make plastic. This type of plastic will later make it easier for us to choose the one that is suitable for our needs and can be recycled or not.
In general, plastics can be divided into seven types of levels. Each type of plastic has a different health hazard and content. So, anyone is advised not to carelessly use various items of plastic material. So, what are the types and what are their uses?
1. PETE ( Polythylene Terephthalate ) or Code 1
PETE or PET is one of the plastics that is often used as a food container and we often find it in various mineral water bottles and food or beverage packaging. This type of plastic can only be used once and certainly not for repeated use.
If we use it repeatedly, it will increase the risk of plastic material and bacteria or germs that develop are also consumed. PETE is a type of plastic that is difficult to clean from bacteria and can be toxic if used incorrectly.
2. HDPE ( High-Density Polyethylene ) or Code 2
HDPE is a type of plastic that is usually found in various types of bottles, for example milk bottles, detergent bottles, shampoo bottles, moisturizer bottles, oil bottles, toys, and some plastic bags. This type of plastic can be said to be the safest for reuse or recycling.
This type of plastic recycling process does not require expensive materials and costs. However, HDPE is recommended for one-time use only because the release of antimony trioxide compounds continues to increase over time. These compounds can cause various problems, such as causing skin irritation, causing respiratory problems, causing disruption of the menstrual cycle, and causing miscarriage.
3. PVC ( Polyvinyl Chlorida ) or Code 3
PVC plastic is a type of plastic that is soft, flexible, and recyclable. This type of plastic is often used to make food wrappers, vegetable oil bottles, plastic pipes, computer and IT cable components, and children’s toys such as swimming floats. However, it is feared that this type contains various poisons that can contaminate food. Therefore, it is highly recommended not to use this PVC as a food wrapper.
4. LDPE ( Low-Density Plyethylene ) or Code 4
LDPE is commonly found in clothes wrappers, dry cleaning bags, fruit wraps to keep them fresh, and bottles of lubricants which has a low level of toxicity compared to other plastics. However, it is very unfortunate because this type of plastic is not for recycling. This is because recycled LDPE is used as a material for making floor tiles.
5. PP ( Polypropylene ) or Code 5
PP plastic is strong, lightweight and heat resistant. This type of plastic is able to protect the material inside from various external disturbances such as moisture. Not only as food packaging, this plastic is also used as buckets, margarine boxes, yogurt, straws, rope, insulation, and paint plastic cans because it is considered safe to reuse and can be recycled.
6. PS ( Polystyrene ) or Code 6
Polystyrene or styrofoam is a cheap, lightweight, and malleable plastic that we often encounter in our surroundings. This plastic is often used as soft drink bottles, egg cartons, food boxes, and wrapping materials to be sent over long distances. However, it is highly recommended to avoid using this type of plastic because it can trigger cancer, disorders of the reproductive system in the body, and various other health problems.
Polystyrene plastic can also emit styrene when in contact with food and drinks, especially when hot. Styrene substances are reported to cause many health problems, including brain damage, disrupting the female hormone estrogen which results in reproductive problems, disrupting growth and the nervous system. In addition, this material also contains benzene which is one of the causes of cancer.
7. Other Plastic Materials (BPA, Polycarbonate and LEXAN) or Code 7
Plastic category with code 7 is more often used in the manufacture of vehicle accessories or other factories. However, the use of this plastic is also used as raw material for baby drink bottles and food packaging which is actually not recommended because it contains substances or compounds such as BPA ( Bisphenol A ) which can interfere with the body’s hormones.
Plastic Classification
Plastics can also be classified under the following categories:
1. Physical properties
- Thermoplastic, which is a type of plastic that can be recycled or printed again by a reheating process. Examples: polyethylene (PE), polystyrene (PS), polycarbonate (PC), and ABS.
- Thermosetting, which is a type of plastic that cannot be recycled or printed again. Reheating will cause damage to the molecules. Examples: epoxy resin, bakelite, melamine resin, and urea-formaldehyde.
2. Performance and Usage
- Commodity plastic, namely a type of plastic that has poor mechanical properties and is not heat resistant. Its application in electronic goods, food packaging, and beverage bottles. Example: PE, PS, ABS, PMMA, and SAN.
- Engineering plastics, namely a type of plastic that is heat resistant, operating temperature above 100 °C, and has good mechanical properties. Its application in automotive and electronic components. Example: PA, POM, PC, and PBT.
- Special engineering plastics, namely a type of plastic that has an operating temperature above 150 °C and very good mechanical properties (tensile strength above 500 Kgf/cm²). Its application in aircraft components. For example: PSF, PES, PAI, and PAR.
3. Based on the Number of Carbon Chains
- 1~4 Gases (LPG and LNG).
- 5~11 Liquid (gasoline).
- 9~16 Liquid with low viscosity.
- 16 ~ 25 High viscosity fluids (oil, grease).
- 25~30 Solids (paraffin and wax).
- 1000 ~ 3000 Plastics (polystyrene and polyethylene).
4. Based on the source
- Natural polymers, namely wood, animal skins, cotton, natural rubber, and hair.
- Synthetic polymers, namely types of plastics that exist in nature, but are made through artificial processes (synthetic rubber. Modified natural polymers are celluloid and cellophane (the basic ingredients are cellulose, but have undergone radical modifications, thus losing their original chemical and physical properties) Examples are nylon, polyester, polypropylene, and polystyrene.
5. Plastic Manufacturing Process
- Injection molding, namely plastic ore ( pellets ) melted by a screw in a heated tube is injected into the mold.
- Extrusion, in which plastic ore (pellet) is melted by a screw in a heated tube is continuously pressed through an orifice to produce a continuous cross section.
- Thermoforming, in which a heated plastic sheet is pressed into a mold.
- Blow molding, namely plastic pellets ( pellets ) that are melted by a screw in a heated tube are continuously extruded to form a pipe (parison), then blown into the mold.
The Danger of Plastic Waste for Humans and the Environment
The amount of plastic waste around us has a direct impact on humans and the environment. Most of this plastic waste comes from single-use plastic packaging, most of which are very difficult to recycle, let alone decompose in nature.
Excessive consumption of plastic has recently become a major concern of the world community. This is because the danger of plastic waste that threatens the sustainability of human life and the earth is very, very terrible. Therefore, the use of plastic should be limited, even reduced for the benefit of all of us.
Here are some of the dangers of plastic waste that humans need to avoid:
- Polluting soil, groundwater and underground creatures.
- The toxins from plastic particles that settle into the soil will kill decomposing animals in the soil such as worms.
- PCB cannot be decomposed, so it can be a chain poison for animals, plants and humans.
- Types of single-use plastic packaging can interfere with waterways that seep into the ground.
- Plastic waste in nature can reduce fertility due to obstruction of air circulation in the soil and space for soil-fertilizing creatures to move.
- Plastic packaging is very difficult to decompose and can take hundreds to millions of years.
- Endanger animals, especially those on land and at sea.
- Plastic waste that is thrown carelessly into rivers will result in silting of rivers, blockages of river flows, and flooding.
How to Minimize Plastic Use
After knowing the types of plastic and the dangers they can cause, you can participate in reducing their use so you can avoid the dangers. Here are steps that are easy to do and you can start from daily habits:
- Replace plastic shopping bags with cloth bags.
- Always bring your own water bottle.
- Avoid using plastic straws.
- If you receive a plastic bag, save it for safe use over and over again.
Well, now we don’t need to be afraid of the danger, but must be wise in responding to it. Come on, take care and preserve the environment by reducing the use of plastic in our lives. It is time for us to reduce the use of plastic to protect living things and also our earth.
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