The word plastic has Greek roots and is derived from the Greek word Plastikos meaning “to shape or place inside a mold for molding”. The SPI Plastics Industry Association provides a much more precise and specific explanation in this regard. The association defines plastics as follows: “Each of the large and distinct groups of materials, in whole or in part, in its chemical structure, including compounds of carbon with oxygen, nitrogen and hydrogen, or other organic elements, and
They are mineral so that in their final state, they take on a solid state and in several stages of their manufacturing process, they take on a liquid form, and as a result, they are able to form three-dimensional objects in various shapes that The process of forming them is the result of using groups of materials individually or joined together under the influence of heat and pressure.
is.”
An English chemist named Joseph Priestley first coined the term rubber rubber after he discovered that a piece of natural latex erased pencil writing well. Natural rubber can be placed in a large group of polymers called “elastomers”. Elastomers are natural or synthetic polymeric materials up to 200% of their original length
And at room temperature they can stretch and return to their original length almost quickly.
History of plastics
It is very difficult to imagine living without plastics today. In our daily activities, we depend on plastic goods such as bottles, glasses, telephones, nylons and many other plastic objects. In any case, more than a hundred years have not passed since the history of plastics in our present form, and a hundred years ago they did not exist today. Long before the development of commercial plastics, some existing materials exhibited unique properties
Have left. Although plastics are strong, translucent, lightweight, and moldable, there are only a handful of materials that exhibit such properties when combined with the desired quality. Today, these materials are referred to as natural plastics.
Natural plastics have benefited from the combination of the following properties over the centuries: light weight, mechanical strength, resistance to water penetration, opacity and semi-transparency, and moldability. Their potential was obvious, but they were materials that were difficult to collect or only available in limited volumes or dimensions. Many people around the world have tried to improve, optimize, or find alternatives to natural plastics.
In the process of making and producing modified natural plastics, natural raw materials such as cotton or linen seeds or gum rubber were transformed into new and better forms. Celluloid had more advantages and quality than horn, which showed its superiority in practice. However, the modified materials were still based on natural resources for the first two components. Buckley opened the door to the development of a group of synthetic polymers that were formulated and designed to provide specific conditions.
Exploration for improved materials continues to this day. Many new fibers are the result of efforts to make artificial silk. Compositematerials are now used in all applications that were previously specific to metals. The possibilities for finding new replacements seem endless.
Evolution of plastics
• Natural plastics
• Modified natural materials
• Old synthetic or synthetic plastics
• Commercial synthetic plastics
Natural plastics
• Horn
• Glass varnish
Gutta-percha (a type of natural rubber with a trans structure)
Old modified natural materials
• Rubber
• Celluloid
Synthetic or old made plastics
Commercial synthetic plastics
Natural plastics
The starting point for these plastics was in medieval England.
• Horn
• Glass varnish or shellac:
In the evening of 1290, when Marco Polo returned to Europe from a trip to Asia, he brought glass lacquer with him. He found glass lacquer in India, where people have been using it for centuries. They discovered the unique properties of a natural polymer obtained from insects instead of cow horns.
The polymer-producing insect was a bedbug insect called Lac, which lives in India and Southeast Asia.
Gutta percha or natural rubber with trans structure:
Gota Persha is a natural polymer with remarkable properties. It is made from Palaquium gutta trees, a native tree of the Malay Peninsula. In 1843, William Montgomeria reported that in Malaya, gutta-percha was used to make knife handles. The material softens in hot water and is pressed by hand to its desired shape. His report aroused interest in the substance and led to the formation of the Gutta percha company, which operated until the 1930s. The company made and produced molded goods.
The features of the gutta-percha are unusual. At room temperature, it is solid and can be dented and dented, but does not break easily. Due to heat, it can be made into long strips (