1) Introduction to materials
What are the materials and what is their use?
Materials are physical substances that are used in making objects and things. When studying the mechanics or any other engineering field, a person will come across the word raw materials. This term stands for a feedstock or unprocessed material that will be used in the creating and manufacturing of goods, products, etc.… There is a wide variety of materials in the world, and each material has its own characteristics. These characteristics are called PROPERTIES OF MATERIALS. So what are these properties?
- Mechanical Properties: They include strength, toughness, ductility…
- Physical Properties: They include density, electrical conductivity, thermal conductivity…
- Chemical Properties: Chemical Properties refer to such issues as corrosion resistance, …
- Manufacturing Properties: Manufacturing Properties include formability, machinability, ease of joining…
Types of materials
There is a wide variety of materials and they can be classified into different classes and categories such as:
- Biomaterials: These are materials and substances that are designed by engineers to interact with biological systems. Biomaterials can be used for medical purposes either to repair and treat or to simply diagnose.
- Ceramics: ceramics are nonmetallic materials that are composed of inorganic molecules.
- Composites: composites are materials that are in the form of a mixture of at least two other substances.
- Metals: metals are materials known for their excellent heat and electrical conductivity. They are also malleable and optically reflective.
Classes and types of materials can also be divided into two different classes and categories:
- Natural materials: such as wood and stone that are found in nature.
- Synthetic materials: which are manmade such as plastic and steel.
2) Introduction to plastics
definition of plastic
Plastic is a synthetic organic polymer. It is true that there are many types of plastics; however, they all include carbon and hydrogen.
Plastic is one of the most commonly used materials in industrial fields and facilities. Polymers and plastics have certain characteristics or properties that make them unique and extremely important such as:
- Durability: plastics are considered to be durable with a slow rate of degradation.
- Poor conductibility: plastics are poor for conducting heat and electricity.
- Solid: plastics in most cases are in the form of a solid substance.
- Stiffness: some polymers tend to be really stiff which may be considered as a drawback or an advantage.
types of plastic
Plastics can be divided into two major categories:
- Thermoset: originally thermoset plastics are in liquid form; however, once they cool and harden, they retain a shape and cannot return to their original form. Thermoset plastics are usually hard and durable. They can be used in various fields and domains such as aerospace and automobile fields.
- Thermoplastics: thermoplastics can be heated and soften. They are easily molded in extruded form; however, they are less rigid than thermosets.
3) Top 7 most important types of plastic
- Polyethylene terephthalate: also known as PET, is the most commonly used and most common substance for thermoplastic resin. PET is used for many purposes such as clothing, containers for liquids and foods such as water bottles.
- Polyvinyl Chloride: also known as PVC is the plastic that is mostly used for construction purposes such as plumbing and insulation of electrical wires. PVC has certain properties such as being brittle, rigid and strong that makes it unique.
- Polypropylene: also known as PP is a type of plastic that is notoriously known for its use in living hinges. However, it is also used in the automotive industry and packaging for consumer products. PP is also very easy to repair from damage and can easily adapt to various methods and techniques of manufacturing.
- Polylactic Acid: also known as PLA is a very unique type of plastic. While most plastics are derived from petroleum, PLA is actually derived from biomass. PLA has lots of benefits such as its biodegrading which is much quicker and faster than other plastics. It can also be used in 3D printing.
- Polycarbonate: also known as PC is a type of plastic that is transparent. Surprisingly enough, PC actually have a high strength. It is usually used for creating greenhouses and riot gear for the police.
- Acrylic: also known as PMMA, is a type of plastic that is extremely transparent and is usually used for creating optical devices such as contact lenses. When PMMA lenses or products for the eye break or shutter, they are not likely going to do any damage to the eye or the skin. The reason is that PMMA is extremely resistant to scratch.
- Nylon: or PA is used in various fields and domains especially in clothing applications, car tires and injection molded parts of cars and vehicles. Nylon is also known for being highly strong and resistant to temperature.
In the previous list there is no type of plastic by any means better than another; however, each type is more suitable to use than another in certain applications. So in order to choose the type of plastic for different applications, there are certain properties and factors that should be taken into consideration such as:
- The strength of the plastic
- Ductility of the plastic
- Electrical and thermal conductivity
- Transparency of the plastic
- The Price and cost of the plastic
- Degradation process of the plastic
- How easy is it to be used in certain manufacturing technique such as 3D printing?
- How rigid the plastic is
- Impact resistance
In conclusion, plastics and polymers are extremely used as raw materials in almost every field and domain in the world, whether that be the medical field, mechanical engineering, manufacturing facilities, or even agriculture such as the creating of greenhouses. The variety of plastics that are available to the public and business owners have pushed technology to another level.