Don't just know about high-temperature nylon! these 5 plastics can also withstand the test of fire

1. PPO (Polyphenylene Oxide)

PPO is an amber-colored transparent material with a specific gravity of approximately 1.06, which is close to that of water.

• Combustion characteristics: flame retardant, extinguishes immediately after being removed from fire, produces thick black smoke when burning, and emits a floral and fruity smell in a molten state.
  
  
• Core Advantages:
• It has the highest glass transition temperature (210°C) among thermoplastic materials, with outstanding high-temperature resistance.
• It can withstand boiling water and steam at high temperatures without deforming or decomposing.
• The material is hard and tough, with better creep resistance than PA, POM, and PC, and has a higher surface hardness.
• Excellent low temperature performance, maintaining good extensibility at -135℃ with strong dimensional stability.
• Excellent dielectric properties, stable across a wide range of frequencies, temperatures, and humidity.
• Supports metallization processes (electroplating or vacuum coating).
• Main shortcomings: Exposure to organic solvents can easily lead to stress cracking; poor weather resistance, easily discolored by sunlight; poor fluidity, making processing difficult.
  
  
• Applicable scenarios: Suitable for environments that are humid and under load, requiring excellent dielectric performance and high mechanical performance, such as tuning plates, microwave insulation components, water treatment equipment, medical devices, food contact materials, and high rigidity electrical enclosures, with performance superior to PC.
  
  
• Injection Molding Key Points: Crystalline plastics, melting point at 217°C, decomposition temperature at 360°C, processing temperature usually between 280-340°C; requires drying treatment, drying at 140°C for 2-4 hours can remove moisture to avoid decomposition during processing.

In addition, although the modified product of PPO, NORYL, has significantly lower mechanical properties compared to PPO, its performance can rival that of PC and can be used as a substitute in certain scenarios.

2. PPS (Polyphenylene Sulfide)

PPS is naturally white, has high crystallinity, and is hard and brittle with excellent thermal stability, combining the high resistance of thermosetting plastics. It should be noted that pure PPS cannot be directly injection molded (it tends to partially cross-link at high temperatures, resulting in poor flowability). The PPS available on the market for injection molding is all modified products, with fillers and modifiers added.

• Combustion characteristics: non-combustible, extinguishes immediately after leaving the fire; produces a metallic "clinking" sound when struck together.
  
  
• Core Advantages:
  • Resistant to various solvent corrosion in high-temperature environments.
  • The creep resistance is strong, and other mechanical properties are also relatively outstanding.
  • Maintains mechanical properties and dimensional stability at high temperatures.
  • Excellent dielectric properties, minimally affected by frequency, temperature, and humidity.
• The main drawbacks are poor impact resistance and brittleness.
  
  
• Applicable scenarios: Suitable for high-temperature, humid, and load-bearing environments, and can be used as insulation, anti-corrosion, and insulating materials.
  
  
• Key Points for Injection Molding: Crystalline plastic, melting point 280°C, decomposition temperature 400°C, processing temperature generally 300-340°C; hygroscopic, moisture will cause decomposition during processing, needs drying at 140°C for 2-4 hours.

3. PSF (Polysulfone)

PSF is mostly a transparent material with a slight amber tint (some are ivory-colored and opaque), with a medium specific gravity (1.24).

• Combustion characteristics: flame-retardant, extinguishes after removal from fire, with a flame accompanied by yellow-brown smoke, emitting a burnt rubber odor when melting during combustion.
  
  
• Core Advantages:
• Outstanding high and low temperature resistance, maintaining 80% mechanical strength at 150°C and 75% mechanical strength at -100°C.
• Excellent creep resistance and long-lasting mechanical strength stability.
• High dielectric performance is strong, remaining stable at a high temperature of 190°C, as well as in water or humid environments.
• Outstanding radiation resistance.
• Supports metallization processing (electroplating or vacuum coating).
• Main drawbacks: Although it is not easily hydrolyzed, water can cause stress cracking under high temperature and load conditions; it has poor fluidity and is difficult to process.
  
  
• Applicable Scenarios:
• Manufacturing electrical and electronic components that require precise tolerances, high rigidity, thermal stability, and good electrical insulation.
• Parts requiring thermal performance, chemical resistance, durability, and rigidity.
• It is not easily hydrolyzed at low temperatures and can be used for parts of low-temperature water treatment equipment, pump components, water valves, washing machine accessories, etc. It performs better than PC when used as a high-rigidity housing material.
• Key points of injection molding: The injection molding temperature is relatively high, ranging from 280-320°C; the injection molding conditions for modified PSF are similar to those of PC, and the drying temperature should also refer to the PC standards.

4. Polyarylate

Polyarylate is a transparent material, represented by the grade U-100.

• Combustion characteristics: flammable, self-extinguishing after removal from fire; produces a small amount of non-toxic smoke when burning.
  
  
• Core Advantages:
  • It has excellent heat resistance without fiberglass reinforcement.
  • Self-extinguishing without the need for flame retardants, produces low and non-toxic smoke when burning, and meets safety specifications.
  • Low thermal expansion coefficient, low creep, low hygroscopicity, resistant to acid and oil corrosion.
• Main drawback: not resistant to alkalis and organic solvents.
  
  
• Application scenario: Suitable for household appliance manufacturing due to its outstanding safety and stability.
  
  
• Key points of injection molding: Drying is required before processing, bake at 100-120°C for 4-6 hours; the injection molding temperature is 330-350°C.

5. Polyarylsulfone

Polyarylsulfone is a transparent material with a slightly higher density than polysulfone, with the representative product being Astrel 360.

• Core advantages: Heat resistance far exceeds PSF, with heat distortion temperature and continuous use temperature approximately 100°C higher than PSF; mechanical strength is similar to polysulfone.
  
  
• The main drawbacks are poor liquidity and high processing difficulty.
  
  
• Applicable scenarios: As a super high-temperature resistant material, it is suitable for special scenarios with extremely high requirements for temperature resistance.
  
  
• Injection Molding Key Points: The processing temperature range is 320-410°C, and the mold temperature should be controlled between 232-260°C. It has strong hygroscopicity and needs to be dried before processing. Drying at 260°C for 2-4 hours can ensure moisture removal.