Plastic key features:
① most plastic lightweight, chemically stable, will not rust;
② good impact resistance;
③ has good transparency and abrasion resistance; ④ insulation, and low thermal conductivity;
⑤ general formability, good color, low processing costs;
⑥ most plastics poor heat resistance, thermal expansion, easy to burn;
⑦ poor dimensional stability, easily deformed;
⑧ most plastics poor low temperature resistance, low temperature brittle;
⑨ easy to aging;
⑩ certain plastics soluble in solvents.
Plastics can be divided into two types of thermosetting and thermoplastic, the former can not be re-shape to use, which can be repetitive.
Plastic polymer structure, there are two basic types:
The first is a linear structure, a polymer compound having such a structure is called a linear polymer compound;
The second body structure is a polymer compound having such a structure is called a polymer compound body. Some polymer having a branched chain, a branched polymer known as belonging to the linear structure. Although some polymer intermolecular crosslinking, but crosslinking less known network structure, body structure belongs.
Two different structures, showing two opposite properties. A linear structure (including the branched chain structure) of the polymer molecules due to the presence of a separate, and therefore, flexibility, plasticity, can be dissolved in a solvent, the heating can be melted, the hardness and brittleness of smaller features. Since there is no independent body structure of polymer macromolecules exist, so there is no elasticity and plasticity, can not dissolve and melt, only swelling, hardness and brittleness. Polymer plastic has the two structures, made by the linear polymer is a thermoplastic plastic, a polymer made by the body are thermosetting plastics.
Compared with other plastic materials
resistance to chemical attack
shiny, partially transparent or translucent
is a good insulator mostly
Light weight and sturdy
can be processed easily mass-produced, inexpensive
versatile, multi-utility, easy coloring, and some high-temperature plastic is also divided into pan with plastic and plastic, the main purpose is to define the breadth, such as PE, PP cheap, available in a variety of different types of production of the machine. Plastic is more expensive, but raw material stability
And physical properties are much better, in general, it also has two characteristics of rigidity and toughness.
Plastic advantages:
1, most of the plastic of the corrosion resistance, strong acids, bases and the reaction is not.
2, low-cost plastic.
3, durable, waterproof, lightweight.
4, easy to be made into different shapes of plastic.
5, is a good insulator.
6, the plastic can be used in the preparation of fuel oil and fuel gas, which can reduce oil consumption.
Disadvantages of plastic
1, the recycling of waste plastics, classification is very difficult and economically viable.
2, plastic is easy to burn, produce toxic gases when burned. Such as polystyrene produced during combustion of toluene, a small amount of this substance can cause blindness, vomiting and other symptoms of inhalation, PVC burning will produce toxic hydrogen chloride gas, in addition to burning, is a high temperature environment, will lead to plastics decompose toxic ingredients, such as benzene and so on.
3, the plastic product is made of petroleum refining, petroleum resources are limited.
4, the plastic can not be natural decomposition.