Inventory of 8 Common High-temperature Resistant Engineering Plastics

Common High Temperature Engineering Plastics Are Divided into The Following 8 Categories

Introduction

High Performance Resin Studio

Plastics can be classified into general-purpose plastics, engineering plastics and high-temperature engineering plastics according to the classification of long-term use temperature, of which high-temperature plastics are also known as heat-resistant plastics, high-performance plastics, special engineering plastics and so on.

General-purpose plastics have a long-term use temperature below 100℃. Usually include PE, PP, PS, PVC, ABS. general-purpose plastics are the largest category of plastics we use in daily life, usually used as packaging, daily necessities, toys and so on. The long-term use temperature of engineering plastics is around 100℃ to 150℃. The five major engineering plastics include PA, POM, PBT, PC and PPO. they are usually used in mechanical parts, automobiles, electrical and electronic appliances. High-temperature engineering plastics are used at temperatures above 150°C. In addition to high heat resistance and flame retardancy, these materials usually have excellent machinability, aging resistance, dimensional stability and excellent electrical properties. They can be used to replace metal materials and are widely used in electronic and electrical appliances, aerospace, medical devices, automotive, and military fields. It is the material at the top of the plastic pyramid.

I. High temperature nylon

High temperature nylon is divided into three categories:

1. Aliphatic nylon - PA46

PA46 is an aliphatic polyamide condensed from butanediamine and adipic acid. Compared with PA6 and PA66, PA46 has a higher number of amides per given length of chain and a more symmetrical chain structure, which allows it to crystallize as high as 70% and gives it a very fast crystallization rate.

PA46 melting point of 295 ° C, not reinforced PA46 HDT (heat distortion temperature) of 160 ° C, while after the glass fiber reinforced, its HDT can be as high as 290 ° C, the long-term use of the temperature is also 163 ° C. PA46's unique structure gives other materials can not be reached by the unique performance!

PA46 is mainly used in electronics, aerospace, automotive.

2. Semi-aromatic nylon - PPA

PPA by the benzene ring containing dibasic acid and aliphatic diamine polycondensation, its melting point between 310-325 ℃, heat distortion temperature between 280-290 ℃. The main varieties are PA4T, PA6T, PA9T, PA10T and so on.

Compared with ordinary PA66, PPA's water absorption is very low, even if soaked in cold water for several years, its tensile strength can be maintained more than 80%, and PPA is very good oil resistance, even at high temperatures also has a very high resistance to lubricants, fuel oil.PPA also has excellent dimensional stability and weather resistance.

Commonly used in automobiles, electrical and electronic appliances, machinery industry, daily necessities.

3.Full aromatic nylon - PARA

PARA was invented by DuPont, the most famous of which is Nomex (polyisophthaloyl mesophthalamide also known as aramid 1313) and Kevlar (all-para polyarylamide also known as aramid 1414).

These materials are mainly used to prepare high-performance fibers and sheets, made of fibers with high strength, high rigidity, high modulus, high heat resistance, high dielectric strength.

It can be applied to super-strong fibers and reinforcing materials for structural components in military, aviation and aerospace.

II. Polyphenylene sulfide (PPS)

Polyphenylene sulfide (PPS) is the fastest growing and most used special engineering plastics in recent years, with excellent high temperature resistance, chemical resistance, weather resistance, flame retardancy, and electrical properties, good dimensional stability, etc., it is widely used in automotive, electrical and electronic, machinery industry, petrochemical, pharmaceutical, light industry, and the military, aerospace, 5G communications and other fields, it is the most widely used special It is the most widely used special engineering plastic.

PPS is also the special engineering plastics with the highest degree of localization in China, and the self-sufficiency rate can reach more than 80%.

According to incomplete statistics, the global polyphenylene sulfide (PPS) production capacity of major enterprises exceeds 200,000 tons. From the point of view of capacity distribution, the current global polyphenylene sulfide (PPS) industry capacity is mainly concentrated in Japan, China.

DIC, Toray, Solvay, Wu Yu and other traditional PPS giants in PPS production, technology and other aspects are still relatively leading, their four production capacity accounted for more than 56% of global capacity. But Chinese companies show a rapid rise in momentum, Zhejiang Xinhecheng, Chongqing Poly Lion and other domestic enterprises have formed a large-scale production, and many other companies have been mass production or in the planning layout.

III. Polyaryletherketone (PAEK) class

Polyarylene ether ketone (PAEK), is the main chain by the phenylene ring through the ether bond, ketone bond connected to the polymer, according to the ether group, ketone group number and order can be divided into polyether ether ketone (PEEK), polyether ketone (PEKK), polyether ketone (PEK), polyether ketone ether ketone ketone (PEKEKK) and so on.

1.PEEK (polyether ether ketone)

PEEK is a special engineering plastics with excellent comprehensive performance. Its heat resistance, water resistance, solvent resistance, excellent electrical insulation; high fatigue strength; radioactivity resistance is the best of all plastics; high oxygen index, combustion produces less smoke and non-toxic.

2.PEK (Polyetherketone)

PEK due to its molecular structure of the ether bond and the proportion of ketone group is lower than PEEK, so its melting point and glass transition temperature are higher than PEEK, heat resistance is better than PEEK, continuous use temperature of 250 ℃.

3.PEKK (polyether ketone)

PEKK Chinese name polyether ketone ketone, is a high-performance materials. This material has a high melting point, almost 300 ° C to 600 ° C, as well as strong chemical resistance and wear resistance. The application of PEKK in the field of 3D printing has progressed rapidly in recent years, and it has better performance than traditional 3D printing materials.

IV. Polyimide (PI) class

Polyimide (PI) is a molecular structure containing imide-based chain links of aromatic heterocyclic polymer compounds, is currently one of the best varieties of engineering plastics heat resistance, can withstand extreme temperatures, thermal decomposition temperature of up to 600 ° C, -269 ° C in liquid helium will not be brittle. It also has excellent mechanical, acid and alkali resistance, biocompatibility and electrical properties.

Polyimide for high-performance components

Polyimide engineering plastics can be divided into both thermosetting and thermoplastic, can be divided into poly(tetramethylene tetraimide) (PMMI), polyetherimide (PEI), polyamide monoimide (PAI), etc., in different fields have their own uses.

Special conditions of precision parts, high temperature self-lubricating bearings, seals, blower impellers, etc. can also be used in contact with liquid ammonia valve parts, jet engine fuel supply system parts.

PEI has excellent mechanical properties, electrical insulation properties, irradiation resistance, high temperature resistance and abrasion resistance, good melt fluidity, molding shrinkage rate of 0.5% to 0.7%, available for injection and extrusion molding, post-processing is easier, can also be used for welding method and other materials combined in the electronics and electrical appliances, aerospace, automotive, medical equipment and other industries are widely used.

The strength of PAI is the highest among the current non-reinforced plastics, the tensile strength is 190MPa, the bending strength is 250MPa, and the heat distortion temperature is as high as 274°C under the load of 1.8MPa. PAI has good resistance to ablation and electromagnetism at high temperatures and frequencies, and it has good adhesion properties to metals and other materials, and it is mainly used for gears, bearings, and separating claws of photocopying machines, etc., and it can be used for ablative materials, permeable materials and structural materials of aircraft.

V. Polysulfone (PSU) class

PSU is a slightly amber-colored, amorphous transparent or translucent polymer with excellent mechanical properties, rigidity, wear resistance, high strength, even at high temperatures, but also maintains excellent mechanical properties is its outstanding advantage; its range of -100 ~ 150 ℃, the long-term use of the temperature of 160 ℃, short-term use of the temperature of 190 ℃.

Polysulfone has ordinary bisphenol A type PSU (that is, commonly known as PSU), polyphenylsulfone and polyethersulfone.

1. The molecular formula of ordinary bisphenol A-type PSU:

The conjugation effect of the sulfone group provides oxidation resistance and thermal stability; the ether chain improves toughness and the benzene ring ensures its mechanical strength and modulus.

2. Molecular formula of polyphenylsulfone PPSU:

The benzene ring on the main chain of polyphenylsulfone provides high heat resistance and mechanical properties; the ether bond provides excellent fluidity and processing properties.

3. Molecular formula of polyethersulfone PESU:

The ether group provides flexibility and high fluidity, the sulfone group provides heat resistance, and the phenylene group provides rigidity.

Comparison of the properties of bisphenol A type polysulfone, polyarylsulfone, and polyethersulfone

VI. Polyarylate (PAR)

Polyarylate (PAR) is a thermoplastic resin containing a benzene ring and an ester bond on the main chain.PAR has good light transmittance (close to 90%), toughness, heat resistance, elastic recovery, weathering and flame retardant properties, with a continuous use temperature of up to 170°C. It is mainly used in precision devices, automobiles, medical devices, and other applications. It is mainly used in precision devices, automotive, medical, food and daily necessities.

PAR structure is similar to PC, its performance is largely the same, can share the mold molding, but PAR's main chain on the aryl ring density, making PAR heat resistance is better than PC, heat distortion temperature is higher than the PC 20 ~ 40 ℃, and ultraviolet resistance, creep resistance is excellent. But the elongation at break and impact resistance is not as good as polycarbonate.

Comparison of the performance of PAR and PC

VII. Liquid Crystal Polymer (LCP)

LCP Chinese name for liquid crystal compounds, the so-called “liquid crystal” is in the molten state both the fluidity of the liquid, but also to maintain the molecular order of the crystal arrangement of the substance.

LCP's mechanical properties are excellent, the biggest feature is that with the thinning of the wall thickness, the relative strength increases, LCP has good thermal properties, continuous use of the temperature can reach 200 ℃ -300 ℃.

The dielectric constant and dielectric loss of LCP are very small, so it is used in electronic devices, such as connectors, slots, switches, brackets and sensors. The most widely researched concern is the application of 5G antennas for cellular phones.

VIII. Fluoroplastics

Fluoroplastic (Fluoroplastie) refers to plastics made from fluorine resin. The main varieties are polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polyperfluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF) and so on. The use temperature is between 150℃-260℃.