91久久久久久精品免费观看,日韩精品无码电影,一级无码日韩精品,国产午夜毛片v一区二区三

On July 14th, 1907, Baekeland registered a kind of plastic patent -- phenolic plastic. Later, PE, PP, PVC, PS, ABS, PC, PA, PBT, pet, PPO, PPA, PPS, LCP, peek, PI, PSU, tpee/tpe/tpv/tpu/eva, sebs/sbs/epdm, PTFE... Have been invented continuously. Over the past 100 years, intelligent scientists and businessmen have brought mankind into the colorful plastic international, electronics, electrical appliances, cars, They all contain many plastic functional parts or clothes, because the engineers' various inspections show that plastic can have special functions that can be imagined, such as insulation, conductivity, weather resistance, chemical resistance, easy coloring, biocompatibility, corrosion prevention, easy molding, recyclability and so on.

Plastics are classified according to the modification of heat. They can be divided into two categories:

[thermosetting plastics] refers to the molecular structure that will form a network after heating. Once the network polymer is formed, it will not soften even after reheating, showing that the so-called [irreversible change] is caused by chemical changes in the molecular structure. The phenolic resin mentioned above is one of the thermosetting plastics, because its irrecoverable characteristics restrict its application, In recent years, it has been replaced by thermoplastic

[thermoplastic] refers to the plastic that will melt after heating and can be moved until the mold is cooled and formed. After reheating, it will melt again. It can be heated and cooled repeatedly to make it [reversible change] (liquid ←→ solid). During this period, as long as the physical change occurs.

Thermoplastics can be divided into general plastics, general engineering plastics and high-function engineering plastics according to their different functions.

General plastics usually refer to PP, PE, ABS, PVC, PMMA, PS, San, etc

And the following is what we want to introduce today:

[engineering plastics]

What is engineering plastics?

Engineering plastics (also known as performance plastics) is a kind of high functional polymer materials that can be used as structural materials to accept mechanical pressure in a wide temperature range and in harsh chemical and physical environments. It is a kind of high-function data with balanced functions such as strength, resistance, heat resistance and hardness. To put it mildly,Jiangmen engineering plastics"Gao Fu Shuai" in plastic work is the backbone of the work

The general engineering plastics industry generally refers to the five major: PC (polycarbonate), pbt/pet (polybutylene terephthalate and polyethylene terephthalate), PA (polyamide), PPE (polyphenylene ether, called PPO by SABIC company) and POM (polyoxymethylene). Of course, there is also a saying in the industry that PC will be classified as general plastics. If there is such a difference, it is the four major engineering plastics.

The five engineering plastics are in the middle of the pyramid. They are the "backbone", with acceptable output value, lower cost than engineering plastics, and better functions than general plastics (heat resistance, chemical resistance, excellent mechanical functions, etc.). PCs are classified as non crystalline plastics, while pbtpappepom, etc. are classified as crystalline plastics, with no calculation. In 2016, the global PC production capacity was more than 5million tons, and the consumption in Chinese Mainland was more than 2million tons, The annual consumption of pompbtpa is more than 500000 tons. At present, the market is still not full, increasing at a rate of 6-10% every year

Engineering plastics belong to the top of the pyramid and have excellent functional performance. Many materials have ' unique secrets'. For example, PI has long-term application temperature, PPS has strong chemical resistance, and peek has excellent biocompatibility; Of course, it also has the "minority plot" of high cost and small consumption

[description]

The above difference methods are common difference methods, which are convenient for work difference and reference. For example, if PP at the bottom of the pyramid is lengthened and reinforced with glass fiber, it will accept higher long-term application temperature. Ultra high molecular weight polyethylene (uhwpe) has chemical resistance and can be classified as engineering plastics;

Source: Jiangmen engineering plasticswww.wywantong. com