The main features
Most plastics are light in weight, chemically stable and resistant to corrosion.
Good impact resistance;
It has better transparency and abrasion resistance.
Good insulation, low thermal conductivity;
General molding, coloring, processing cost is low;
Most plastics have poor heat resistance, high thermal expansion rate and easy to burn.
Poor dimensional stability, easy deformation;
Most plastics are poor in low temperature resistance, brittle at low temperature, easy to aging;
Some plastics dissolve easily in solvents.
Plastics can be divided into two categories: thermosetting and thermoplastic. The former cannot be remolded for use, while the latter can be remanufactured. Thermal plasticity has a large physical elongation, generally ranging from 50% to 500%. The force does not change linearly at different elongation.
Different properties of plastics determine their use in industry. With the development of technology, the modification of plastics has not been stopped. It is hoped that in the near future, plastics can be more widely used after modification, and even can replace steel and other materials and no longer pollute the environment.
Folded molecular structure
There are basically two types: the first is linear structure, with this structure of polymer compounds called linear polymer compounds; The second is the body structure, with this structure of the polymer compound is called the body polymer compound. Some polymers have branched chains, called branched polymers, which are linear structures. Although some polymers have crosslinks between molecules, they are less crosslinked. They are called reticular structures and belong to somatic structures.
Two different structures that exhibit two opposite properties. Linear structure, heat can melt, hardness and brittleness of the characteristics of small. The hardness and brittleness of the body structure are large. Plastic is the polymer of two kinds of structure has, what make by linear high polymer is thermoplastic plastic, what make by bodily form high polymer is thermosetting plastic.
Folded material characteristics
< 1 > resistance to chemical erosion
< 2 > glossy, partially transparent or translucent
< 3 > is mostly good insulator
< 4 > mass light and strong
< 5 > processing easy to mass production, cheap price
< 6 > widely used, utility, easy to color, part of the high temperature resistance
Fold the advantages
1. Most plastics have strong corrosion resistance and do not react with acids or bases.
2. Low cost of plastic manufacturing.
3. Durable, waterproof and lightweight.
4. Easy to be molded into different shapes.
It is a good insulator.
6. Plastics can be used to prepare fuel oil and fuel gas, which can reduce the consumption of crude oil.
1. It is difficult and economically uneconomic to classify waste plastics when they are recycled.
Plastic burns easily and produces poisonous gas when it burns. For example, when polystyrene burns, toluene will be produced, a small amount of this material will lead to blindness, inhalation has vomiting and other symptoms, PVC combustion will also produce hydrogen chloride toxic gas, in addition to combustion, is a high temperature environment, will lead to the decomposition of plastic toxic ingredients, such as benzene.
Plastics are made from petroleum refining products and petroleum resources are limited.
Plastic will not rot under the ground for hundreds, thousands or even tens of thousands of years.
5. Plastic has poor heat resistance and is easy to be aged.
Due to its non-biodegradability, plastic has become the number one enemy of human beings and has led to the death of many animals. For example, monkeys, pelicans, dolphins and other animals in the zoo will mistakenly swallow the plastic bottle no. 1 left by tourists, and finally die of pain due to indigestion. Looking at the beautiful and pure sea surface, close to see, in fact, floating full of all kinds of plastic waste can not accommodate the sea, in the intestines of many dead seabirds samples, found a variety of plastic can not be digested.