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What are temperature polymers? They are polymeric materials, which have been utilized in high temperature and high heat flux environments during long periods.
When considering the heat transfer, polymer and polymer composite's heat transfer occurs through conduction, convection, and radiation. Conduction is the method used for non-decomposing polymers. Heat transfer in thermally decomposing polymers occurs through convection or flow of decomposition gases. The polymer is usually in the range of 0.7-2.5kJ/kg-K. Although specific heat is as low as 0.2 and as high as 2.7kJ/kg-K, the specific heat can be decreased due to crystallization. CHOY has described how heat conduction in polymers. They consider the atomic vibrations are the reason for transferring heat in solids.
Response of polymer composites to extreme environments
Polymer composites are often exposed to extreme temperature environments. It is higher than the pyrolysis temperature of the polymer. This exposure can be accidental. Such ablators comprise an important aerospace technology and are used in applications such as rocket motor nozzle linings, recently heat shields, and blast shields for the missile.
How they become thermally resistant
High-temperature thermoplastics take their heat resistance by introducing rigid aromatic rings instead of aliphatic groups in their molecular structure.
CLASSIFICATION
High heat thermoplastic resins divide into 4 groups
- Melt- processable polyamides : polyetherimide, polyamideimide
- Polysulfone : polyethersulfone, polyphenylsulfone
- Polyphenylene sulfide
- Polyarylether ketone : polyether ketone
Why are the High-Temperature plastic values more than metal?
- Good noise and vibration damping
- Electrical and thermal insulation or adjustable conductivity
- Good chemical and corrosion resistance
- Increased design freedom
- Adaptable to high volume production processes
- Adaptable to property modification for specific applications
- Density is low
But sometimes it is not good than metals, as
- Greater thermal expansion
- Poorer creep resistance
- Lower thermal resistance
- Susceptible to UV, moisture, and oxidation
- Not considered to be a vapor barrier
- Lower mechanical properties
- Plastic parts generally must be redesigned over metal parts
MAIN APPLICATIONS AREAS
Automotive
High-temperature thermoplastics are used to manufacture applications in the automotive industry. High heat resistance, dimensional stability, strength, and resistance to a range of chemicals are the most important qualities. Lightness and resulting in greater fuel efficiency are the reasons for the improvement of plastic usage.
- Greater design flexibility
- Reduced development time, and
- Lower assembly costs are the offers with plastics
Uses in automotive
1. Piston components; 2. Seals; 3. Washers; 4. Bearings; 5. Transmission components; 6. Transmission thrust washers; 7. Braking and air conditioning systems; 8. ABS brake systems engineer control systems; 9. Truck oil screens; 10. Starting disks in gears, etc
Electrical and Electronics
- Designs thin walls to reduce costs.
- The ability to meet more stringent technical specifications.
- The desire for higher quality and reliability, driven by expected application lifetimes of 5 to 20 years
- Growing market requirements for flame retardant materials that are either halogen-free or have low halogen content
- Low warpage materials
- Design flexibility and design for manufacturing and assembly (DFMA)
- Miniaturization, which increases the temperature and mechanical requirements of plastic materials.
What polymers are in use?
1. Polyetherimide; 2. Polyphthalamide; 3. Liquid crystal polymers; 4. Polyetherketone; 5. Polyphenylene sulfide; 6. Polsysulfone
They use to manufacture
- Wire insulation for high-temperature applications
- Cable couplings and connectors
- Sub-sea connectors
- Coaxial connector jacks
- Sub-sea controlled environment connectors
- Wafer transport carriers
- Surface-mounted trimming
- Potentiometers
- Appliance handles
- Electrical insulations
- IC packaging trays, etc.
AEROSPACE
In the aerospace market, PEEK polymers work in a wide range than aluminum. They are highlighted in lightness and physical, thermal qualities.The polymers used for aerospace can face high temperatures.in the external parts of the airplanes, peek supply a great resistance to rain erosion.
Polymer used for the electricity system of the airplanes, tubes for wire, and fiber optics.
PEI is a high-temperature polymer, commonly used in the aircraft industry. Air and fuel valves, food tray containers, steering wheels, interior cladding parts, and semi-structural components are the main applications. PES and PSU mainly use as external and internal parts of the airplane.
Products
Airbus interior components; Bow-shaped luggage compartment retainers; Cable conduits; Cable clips; Ventilation wheels inside aviation fans; The suction manifold of aviation pumps; Electrical wire harnesses; Convoluted turbine; Wire insulation; Pump casings; Impellers
INDUSTRIAL APPLICATIONS
We need substances with the qualities of fiction, high temperature, and good chemical resistance.
Thermoplastics are commonly used in industrial applications as they have many advantages over normal plastics. They are flexible, easy to prepare, and light.
Products
Impeller wheels for regenerative pumps; Pump rotors, Multi-pin connectors; Glue gun bushings; Quick coupling systems; Laundry system wheels; Conductivity sensors & seals; Compressor valve plates; Heat exchanger parts
MEDICAL APPLICATIONS
Thermoplastics are commonly used in the medical field.
- Polyphenylsulfone
- Polyetherimide
- Polysulfones (PS) and Polyethersulfones (PES)
- Liquid Crystal Polymers (LCP)
- Polyetheretherketone
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