What are the top High Strength Plastics?
Tensile strength is one of the most important factors within all mechanical properties of plastic materials. It is an important aspect of structural applications. Tensile strength is a plastic material’s ability to rest the maximum amount of tensile stress without being pulled or stressed. Talking about high tensile strength plastics, we have 5 plastics on our list with the industry’s highest tensile strength.
Without further a due, let’s begin the salient list.
- PPS (polyphenylene sulfide)
- PEEK (polyetheretherketone)
- PEI (polyetherimide)
- PAI (polyamide-imide)
1. Nylon –
On our list, coming at number #5, is one of the most commonly known plastic materials with a tensile strength of 12,400 psi (85.4 MPa). Nylon is a high-performance, strong engineering thermoplastic which often used as an alternative for latex, rubber, and silk. It has a relatively high melting point of 232 °C and is used extensively in a wide area of applications like clothing, tire components, rubber, ropes, threads, and automobile parts, etc.
- Excellent electrical insulating properties
- Low dimensional stability
- Readily attacked by mineral acids ad polar solvents
- Good fatigue resistance
- Good impact strength at both high and low temperatures
- Excellent fuel and oil resistance.
- Dyeing is necessary before processing.
Below is a table for typical properties for most common Nylon variations:
Extruded NYLON 6/6
Cast NYLON 6
Oil-Filled Cast NYLON 6
|Flexural modulus||psi||D790||410,000||420,000 – 500,000||
375,000 – 475,000
|Tensile Strength||psi||D638||12,400||10,000 – 13,500||9,500 – 11,000|
|Heat deflection temperature – 264 psi||°F||D648||194||200 – 400||200 – 400|
|Water absorption (immersion 24 hours)||%||D570||1.2||0.60 – 1.20||0.50 – 0.60|
|Maximum continuous service temperature in air||°F||–||210||230||230|
|Coefficient of linear thermal expansion||in/in/°Fx10-5||D696||4.5||5||5|
|Izod Impact||ft-lbs/in of notch||D256||1.2||0.7 – 0.9||1.4 – 1.8|
Electrical and Electronics Applications: Nylon has a wide range of applications in electronics and electrical components. The material has to go through a test called GWIT and UL94. As nylon is a flame retardant, it has a huge advantage for being used in electrical products, especially in miniature and thin design applications.
Food Packaging: Nylon’s high usage in food packaging is due to its excellent puncture resistance, good barrier resistance to gases like oxygen, carbon dioxide, and other gases.
Consumer Products: Salient properties like mechanical resistance, easy shaping, and colorability make it relevant for consumer products.
Automotive: It is mostly used in under the hood parts in automobiles. Features like good chemical and temperature resistance and excellent processability make it a prime alternative metal to be used in automotive parts.
2. PPS (polyphenylene sulfide) –
At #4 stands PPS with a tensile strength of 12,500 psi (86 MPa) and a high melting point of 280 °C (536 F). Its a semi-crystalline, rigid, opaque, high-temperature engineering thermoplastic with an excellent set of properties like high-temperature resistance, dimensional stability, good chemical resistance, excellent mechanical strength, good electrical insulation properties, and natural flame resistance.
It is resistant to acids, alkalies, bleaches, aging, mildew, abrasion, and sunlight.
Automotive: “Under the hood” application, brake, and fuel systems.
Medical Industry: Surgical Instruments
Industrial Applications: Valves, slide bearings, compressor and pump parts, chain guides, and base plates.
Chemical Industry: Bushings, pumps, nozzles, tubes, and rollers.
Electronics industry: Heat shields, connectors, contact rails, chain guides, base plates, contact pressure discs, semicons.
3. PEEK (polyetheretherketone) –
At number 3 comes PEEK, one of the most commonly used engineering thermoplastics in the plastic industry with a tensile strength of 14,000 psi (96.5 MPa). Like PPS, it is also chemical and water-resistant and can operate at a high temperature of up to 250 °C. It belongs to the polyketone family of polymers (PEK, PEEK, PEEKK, PEKK, PEKEKK), amongst the PEEK is the most utilized polymer.
- Good dimensional stability
- Excellent insulation properties
- Long life
- Great sterilization resistance at high temperatures
- Low friction
Automotive: Bearing, washers, seals, bring and air-conditioning systems, active components.
Medical and Healthcare: endoscopes, dental instruments, dialyzers, sterile boxes, canal files, load-bearing implants.
Aerospace: exterior and interior parts, electrical systems, protect wires, convoluted tubings, fiber optic filaments.
Electrical and Electronics: coaxial connecter jacks used in telephones, surface-mounted trimming potentiometers, printed circuit boards, etc.
4. PEI (polyetherimide) –
PEI is the second last contender today as it ranks #2 with a tensile strength of 15,200 psi (105 MPa). It is an amorphous engineering thermoplastic with properties quite similar to PEEK but has lower impact strength. One of the few limitations of polymer is its high cost and suitability with only demanding applications and colorability. It is also readily attacked by polar chlorinated solvents leading to stress cracking.
- Excellent retention of mechanical properties at elevated temperatures.
- It has a phenomenal combination of excellent dimensional stability, flexibility, high specific strength, and rigidity.
- Good UV light resistance and weatherability
- Displays good hydrolytic stability
- High resistance to alcohols, acids, hydrocarbons, and dissolves partly in halogenated solvents.
- Inherent flame resistance without using additives.
- Good electrical properties and remains stable within a wide range of temperatures and microwave frequencies.
Automotive: Bezels, reflectors, thermostat housings, throttle bodies, transmission components, ignition components, fuses, ignition switches, solenoid bodies, gears, pump drives.
Electrical and Electronics: Connectors, printed circuit boards, electrical switches & controls, motor parts, electronic chips, capacitors.
Medical: Membrane applications, surgical instrument handles, and instruments, non-implant prostheses.
5. PAI (polyamide-imide) –
At the end of the list, I’ve got the king of all high-strength plastics, PAI, with a tensile strength of 21000 psi (145 MPa). It’s a strong and stiff material used at highly elevated temperatures where other materials would fail. It has impressive dimensional stability with a high coefficient of friction. That set of properties makes it suitable for applications with machining to tight tolerances.
The common applications include chip test sockets, machinery parts, aerospace components.
1. Which is the toughest plastic?
Ans. Polycarbonate is the toughest plastic of all. It’s 200 times stronger than glass and is warranted against breaks and cracks.
2. What is the difference between tensile strength and yield strength?
Ans. Yield strength is a material’s ability to resist stress without permanent deformation. In contrast, tensile strength is the maximum stress a material can resist while being pulled to stretched before breaking or failing.
3. What is a high-performance polymer?
Ans. A high-performance polymer can retain desirable properties like mechanical, electrical, thermal, and physical properties even when exposed to harsh environments like high temperatures, corrosive chemicals, and high pressure.
4. How can you increase the tensile strength of nylon?
Ans. Nylon’s tensile strength can be increased by increasing individual nanofiber strength and fiber-fiber load sharing. Single-walled carbon nanotubes are also being utilized for increasing the tensile strength of nylon.
5. How can the mechanical properties of materials be improved?
Ans. There are four ways to improve the mechanical properties of polymers. However, these methods won’t make a significant improvement but will make little changes.
- Use hotter mold temperatures.
- Use high injection speed.
- Avoid high melt temperature.
- Injection pressure has little effect.
The Takeaway –
That was my take on high-strength plastics. Kindly take note of the tensile strength of any polymer to get desired results with the production. I’ve spent almost 8 years in the plastic industry; I realized that having a detailed knowledge of your material’s propertoes is one of the most important factors for smooth production and quality products.
Kindly share your reviews in the comment section.
Have a mesmerizing day 🙂