Plastic polymers. Image Credit: Shutterstock.com/Meaw_stocker
Plastic has remained a major material for different purposes across diverse industries. Plastic is a polymer-made synthetic or semi-synthetic material. The material is often used for packaging and plumbing items and can be mixed with other materials to make sporting items like rollerblades® and skateboards. Plastic types include: polyethylene (PE), polycarbonate (PC), and thermoplastic polyurethane (TPU). Manufacturers produce plastics to make up for metal shortcomings, reduce carbon dioxide emissions, and serve as protection from electricity and heat.
The chemical composition of plastic depends on its two categories—polymer and heterochain polymers. Polymers consist of vinyl chloride, ethylene, styrene, and propylene, while heterochain polymers have sulfur, nitrogen, and oxygen in their backbone chains.
In this article, we will discuss plastic, its compositions, purpose, types, and uses.
What Is Plastic?
Plastic is a polymeric material that can be deformed, molded, or shaped without breaking. In other words, plastics are polymers of long carbon chains. Plastics can be categorized based on their chemical composition and processes, density, tensile strength, and heat resistance.
What Is the Purpose of Plastic?
Plastics reduce the emission of carbon dioxide. Items or goods packed in plastic are easier and faster to transport, therefore reducing the number of transport journeys by road vehicle, ship, or aircraft. In the same vein, plastics make transport systems lighter. As a result, transport systems can move faster. This reduces travel hours and allows these transport systems to use less energy, therefore reducing carbon dioxide. Research shows that plastic-designed cars reduce the emission of carbon dioxide by 30 million tonnes annually.
Plastic use in homes reduces energy consumption by 90% through heat insulation. Examples are the insulation of cables and pipes. In food production, plastics reduce food perishability. Foods stored in plastic wraps have a longer life span. Using recyclable plastic materials also reduces carbon dioxide emissions.
What Is the Use of Plastic?
There are numerous uses of plastics in homes and different fields. Some of the uses are:
- Helmets, athletic shoes, racket handles.
- IV and blood bags, syringes, blister packs, gloves, plastic prostheses, and catheters.
- Bumpers, cladding, film skins, film padding, etc.
- Water pipes, vacuum cleaners, flooring, bottles, foam, chairs, tables, acrylic composite surfaces, and bags.
- Disposable cups, plates, spoons, and jars.
- Power cables, data cables, floors, and fitting pipes.
What Material Composes a Plastic?
Raw materials used to produce plastics are natural gas, crude oil, and cellulose. Manufacturing plastic with natural gas involves the conversion of ethane and naphtha into ethylene through cracking. The ethylene is transported in a pipeline to another facility for conversion into polyethylene (polythene).
Crude-oil plastics are known to fracture easily but are non-degradable. Crude-oil plastics are generated from artificial organic polymers (made from natural gas or oil). These plastic types are often used for commercial, medical, and industrial purposes.
Softwood trees are the most used material for cellulose plastics. Deforestation laws, however, hinder the growth of the cellulose plastic market. During production, softwood tree bark is processed in a digester to separate cellulose fiber (resins and lignins), which are convertible to polymers.
How Are Plastics Different From Other Materials Like Metals and Ceramics?
As plastics are made from different materials, they are dissimilar to metals and ceramics.
Plastics are highly malleable and can be converted into numerous shapes easily. Metals, on the other hand, due to their strong metallic bonds, are difficult or costlier to transform into complex shapes. Metals have a shorter life span compared to the polypropylene plastic type. Metals are stronger and durable and, as a result, used for construction and numerous other heavy-duty projects. Plastics have less strength but are still suitable for a vast range of applications. Plastics can withstand chemical exposure to corrosives that cause rust, unlike ferrous metals. Plastics can be damaged when exposed to heat. On the contrary, metals cannot be damaged by low to moderate levels of heat.
Plastics have a low heat tolerance. When exposed to heat, some melt and can be remolded. Ceramics, instead, can tolerate very high temperatures. When made into plates, jugs, or other tableware, however, ceramics are fragile and can break if dropped. These items, when made from plastics, can survive harsher treatment. Items made from ceramics are heavier than plastics, reducing their portability. Plastics require automated manufacturing and are cheaper, unlike ceramics, which are more expensive because of their specialized manufacturing. Plastics and ceramics allow the absorption of moisture and gas differently. Plastics are not airtight, so they allow gas and moisture diffusion. Ceramics can withstand internal pressure; therefore, they don’t leak liquid or gas if used for containers.
What Are the Types of Plastics Used in Manufacturing?
The types of plastic materials used in manufacturing are listed below:
1. Polyethylene (PE)
Polyethylene (PE) has low rigidity but has a high impact strength when compared with other plastic types. It possesses insulation properties and is resistant to acids and alkalis. This plastic type is used to manufacture: ropes, plastic bags and films, laminations, cables, fishing nets, and cable jackets.
To learn more, see our full guide on Polyethylene (PE).
2. Polypropylene (PP)
Polypropylene (PP) is flexible and heat-resistant and is often used for food packaging, storage, or food reheating. Examples include: food containers, straws, and disposable diapers.
3. Polyvinyl Chloride (PVC)
Polyvinyl chloride (PVC) is used across industries like: construction, medicine, and electricity due to its rigid nature. This plastic type is germ- and chemical-resistant and a non-conductor of electricity. It is often used for: oxygen masks, plumbing pipes, and pet toys. Yet, it is harmful to human health as it carries dangerous toxins like lead and vinyl chloride.
To learn more, see our full guide on Polyvinyl Chloride (PVC).
4. Polystyrene (PS)
Polystyrene (PS), also known as Styrofoam™, is used to make egg cartons, shipping packaging, and building insulation. Styrofoam™ is rigid and serves as an insulator. For these reasons, polystyrenes are mostly used in: the packaging, construction, and food industries. Like PVC, PS carries a harmful toxin called styrene.
5. Polyethylene Terephthalate (PET)
Polyethylene terephthalate (PET), a polyester, is recyclable, indestructible (like glass), and strong. Likewise, they are safe on the skin and when in contact with food. Yet, it has low impact strength. PET is applied during the manufacturing of: roof insulation, seat covers, films, beverage containers, and fleece jackets.
To learn more, see our full guide on Polyethylene Terephthalate (PET).
6. Polycarbonate (PC)
As a thermoplastic, a polycarbonate (PC) can be heated, cooled, and reheated without degradation. PC is often used for items that require transparency and high resistance to impact. Its applications include: lenses for eyeglasses, car windows, DVDs, and roofing.
7. Acrylonitrile Butadiene Styrene (ABS)
Acrylonitrile butadiene styrene (ABS) comprises the three monomers in its name: acrylonitrile, butadiene, and styrene. It is an amorphous polymer resistant to abrasion and impact and is rigid. However, it scratches easily and is prone to stress cracking. ABS is used for: door handles, dashboard components, computer keyboards, nebulizers, and compressors.
8. Polyamide (Nylon)
Polyamide is a synthetic polymer with low breathability. It’s prone to pilling, stretchy, and resistant to heat. Polyamide is used to make: firefighting gear, women’s leggings, tights, and sportswear.
9. Thermoplastic Polyurethane (TPU)
Thermoplastic polyurethane (TPU) is used for: adhesives, car wheels, paints, mobile phone casings, hoses, etc. This plastic is non-abrasive, flexible, and durable.
10. Poly(methyl methacrylate) (PMMA)
Poly(methyl methacrylate) (PMMA) is a rigid thermoplastic with several coloring options and resistance to weathering and UV light. It is processed through extrusion and injection molding. Key PMMA applications are: light covers for car indicators, LCD/LED TV screens, incubators, kitchen cabinets, and ship windows.
What Are Some Examples of Thermosetting Plastics and Their Applications?
Examples of thermosetting plastics and some of their applications include:
- Polyimides (PI): Hard disk drive components, wire insulators, cardiovascular catheters, and push rings.
- Furan Resins: Explosive binders, corrosion-resistant coatings, pipes, and wood adhesives.
- Epoxy Resins: Aircraft, bicycle, and vehicle construction, metal coatings, decorative flooring, and adhesives.
- Duroplast: Electricity meters, circuit breakers, and kitchen appliances.
- Cyanate Ester: High-temperature adhesives, radomes, and satellite antenna.
- Vinyl Ester Resins: Surface coating, ladders, and bridges.
- Vulcanized Rubber: Seat belts, rubber hoses, and toys.
- Urea-formaldehyde Resins: Textiles, coatings for electrical appliances, cotton blends, and paper.
- Melamine-Formaldehyde Resins: Veneers, plywood, and paper and wood coating.
- Bakelite: Clocks, washing machines, sockets, wire insulation, and switches.
While plastic serves several purposes across industries, it is also used to produce paper. Plastic paper types are: take-out and frozen-food containers, paper cups and plates, juice packaging, paper bag lining, and waterproof paper.
What Industry Usually Uses Plastic?
Industries that use plastics are:
- Aviation
- Construction
- Transport
- Healthcare
- Textile
- Food
- Engineering
- Sports
- Electrical and electronics
- Military
- Furniture
- Energy
Can Plastic Be Used for Packaging Materials?
Yes, plastics can be used for packaging materials. Companies often use plastic for packaging because it is lightweight, keeps items from damage during transport, protects food from decay, and is often recyclable. Some plastic packaging materials are:
- Stretch film
- Plastic cup noodle packaging
- Blister packs
- Disposable plates
- Carbonated drinks bottles
- Sachets
- Styrofoam
To learn more, see our full guide on Types of Packaging Materials.
Does the Automotive Industry Frequently Utilize Plastics?
Yes, the automotive industry often utilizes plastics because of their heat resistance and durability. Plastics used in the industry include: polyurethane, polypropylene, polyvinyl chloride, polystyrene, polybutylene terephthalate, etc. Some of their applications are:
- Wheel liners
- Seat belts
- Airbags
- Engine covers
- Dashboards
- Headrests
- Splash guards
- Seat cushions
- Car bumpers
- Tires
What ISO Standards Are Applicable to the Manufacturing and Quality Control of Plastics?
The types of ISO standards applicable to the manufacturing and quality control of plastics are numerous and based on different plastic types and uses. These are:
- ISO 7823-1:2003: Spells out the requirements for PMMA cast sheets for general use. This standard shows that cast sheets must be translucent, transparent, opaque, colored, or colorless. The sheets should also be 1.5–25 mm thick.
- ISO 15747:2018: Makes provision for the safe handling and physical, biological, and chemical testing of plastic containers for intravenous injections. The plastic containers, such as film bags, must have one or more chambers. In addition, they must have a nominal capacity of 50 to 5,000 ml.
- ISO 18225:2012: Specifies the requirements for multilayer pipe systems made from thermoplastics and meant for outdoor gas supply. For stress design and inner layers of pipes, the polymeric material to use must be polyethylene or cross-linked polyethylene. Pipes used in these systems should have up to 630 mm nominal diameter.
How Do ISO Standards Ensure Consistency and Reliability in the Production Process of Plastic?
ISO standards ensure consistency and reliability in the production process of plastic by updating its requirements and ensuring that plastic manufacturers can access such updates.
What Is the Advantage of Using Plastic?
The advantages of using plastic are:
- They are non-corrosive.
- Resistance to heat and electricity.
- Low production cost.
- Plastics work effectively across different industries.
- Water, impact, and chemical resistance.
What Is the Disadvantage of Using Plastic?
The disadvantages of using plastic are:
- Some of the plastic types carry toxins harmful to people’s health.
- Plastics are not eco-friendly as they don’t decompose because of their non-biodegradable nature.
What Is the Difference Between Plastic and Polymers?
Even though the terms plastics and polymers are often interchanged, they differ. While all plastics are polymers, all polymers are not plastics. Polymers are made of chains of monomers, and plastics are made from crude oil and natural gas.
Natural polymers do not release toxic fumes when burned, but plastics do. Plastics have a high strength-to-weight ratio and are versatile.
In addition, polymers are biodegradable, while plastics are generally not. Synthetic polymers are divided into: synthetic fibers, elastometers, thermosets, and thermoplastics. Plastics are divided into thermosets and thermoplastics.
Copyright and Trademark Notices
- Styrofoam™ is a registered trademark of the DuPont Company
- Rollerblade® is a trademark of the Nordica sports company
