Plastics comes from the Greek word plastikos, which means to form or to mold. However, plastics do not have a uniformly defined term. Some people define plastics in a narrower sense in which they focus on specific properties, others take a broader approach that includes various manufacturing processes.
Let’s start by looking at plastics as a material.
Plastics materials are composed of large molecules (polymers) that are synthetically made or modified.
Firstly, take a moment to think about all the material available in this world. You will soon realize these materials fall into one of three categories: liquids, gases and solids. While noting that most materials can be converted from one state to another through heating or cooling, let’s narrow our scope on materials that remain solid in room temperature. You are left with metals (iron, copper, gold, etc.), ceramics (stones, clay, etc.) and polymers.
A polymer is a large molecule made up of smaller molecules that are joined together by chemical bonding. Polymers can be divided into natural polymers and synthetic polymers. In natural polymer, the selection of molecules and the process of chemical bonding occur naturally – thus giving us materials like wood, leather, cotton, rubber, hair, etc.
In synthetic polymers, the selection of molecules and the chemical bonding process is man-made. This gives us material like nylon, polyester and polyethylene. It’s worth noting that some synthetic polymers can be “manufactured copies” of natural occurring materials – e.g. synthetic rubber. Modifying the chemical bonding process is another example of how celluloid or cellophane is synthetic ally modified to an extent that the natural polymer characteristic of cellulose is altered.
These are the methods of how synthetic polymers are formed:
o do not occur naturally
o occur naturally but made by non-natural processes
o modified natural processes
In short, all synthetic polymers are considered plastics. The industrial term for plastics raw material is known as plastics resins.
Post time: 12-06-2016