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Top 6 Chemical Resistant Plastics

Hello People, Today I’m going to share an exclusive article on the best chemical-resistant plastic materials suitable for most industrial and residential applications.

Best Chemical Resistant Plastics 

For certain plastic materials, performing well against harsh environmental conditions can be too much to ask, but there are some plastics out there with phenomenal chemical-resistant capabilities. There are several factors influencing how a part will react to chemical attacks. Below are a few of them.

Chemical Concentration: Chemicals with high concentrations are more prone to damage plastics.

Higher Temperature: After a point, escalated temperatures increase chemical attacks and speed up physical absorption.

The Extent of Chemical Damage: The more are covered by the chemical attack, the more substantial the degradation.

Time for Exposure: Damages from chemical reactions wouldn’t necessarily appear immediately. It can take some time to emerge and materialize.

In industrial applications, any conditions are normal but can severely compromise a plastic part’s performance or make it completely useless. If your project is mainly focused on being utilized in extreme chemical environments, then ensuring you use chemical-resistant plastic for the job is a must.

When analyzing chemical-resistant plastics, check which industries commonly utilize these materials. Specific industries, such as food processing, chemical processing, and medicine, use chemically inert materials more.

Without further ado, let’s get started with the best chemical-resistant plastics:

  • PTFE
  • PEEK
  • HDPE
  • Polypropylene
  • PVC
  • PVDF

PTFE

PTFE, also known as Teflon, is a high-performance and versatile fluoropolymer comprised of carbon and fluorine atoms. It has arguably the best chemical resistance among all plastic materials. Organic halogenated compounds only attack it, like chlorine trifluoride (ClF3), oxygen difluoride (OF2), molten alkali metals, and gaseous fluorine at high temperatures.

PTFE has excellent thermal properties with no degradation below 440 °C, outstanding electrical insulating properties, very low dielectric constant (2.0), low coefficient of friction (static 0.08 and dynamic 0.01), and high and low heat resistance. It also has good mechanical properties but is weaker than mainstream engineering plastics. However, the addition of fillers has been highly successful in overcoming those shortcomings. The potential hindering in the fluoropolymers attributes depends on processing inconsistencies preform pressure, sintering temperature, cooling rate, etc.

Applications

Medical: cardiovascular grafts, heart patches, cardiovascular grafts, ligament replacement.

Automotive: shaft seals, power steerings, valve stem seals, gaskets, O-rings, transmission, linings, fuel hoses, etc.

Chemical Industry: autoclaves, reaction vessels, tanks, containers, pumps, diaphragms, impellers, Coatings for heat exchangers, etc.

Engineering: plugs, fittings, valves, pump parts, bearings, non-stick surfaces, reaction vessels, tanks, diaphragms, containers, etc.

Electrical & Electronics: electrical insulation, flexible printed circuit boards.

Interesting Read – 7 Best UV Resistant Plastics For Outdoor Applications

PEEK

PEEK or polyetheretherketone is semi-crystalline, high-performance, rigid thermoplastic with excellent properties, including excellent resistance to harsh chemicals. Commercially available since the 1980s, PEEK has seen exponential growth in its adoption by factories worldwide. Its bouquet of outstanding mechanical properties, resistance to fatigue, wear, and high temperature of up to 260 °C makes it a prime choice for most high-end engineering applications.

PEEK is easy to process and can be effortlessly molded into complex shapes and designs. It is often processed in traditional plastic fabrication methods i.e., injection molding, compression, and extrusion. Another beneficial factor is its smoke and fumes emission is relatively low when exposed to flames, making it a good choice for high-temperature applications.

Below is a table showing the general properties of PEEK material:

Property Unit Value
Physical Properties
Density g mL-1 1.33
Melting Point °C 343 – 387
Coefficient of Thermal Expansion x 10-5 cm / (cm °C) 4.5 – 5.5
Thermal Conductivity W / mK 0.29
Heat Deflection Temperature, 1.8 MPa °C 152 – 172
Rockwell Hardness, M Scale M100 – M124
Mechanical Properties
Tensile Modulus at 23 C MPa 3725
Tensile Strength, Yield at 23 C MPa 100 – 115
Tensile Strength, Break at 23 C MPa
Compressive Strength MPa 120
Flexural Modulus MPa 4065 – 4275
Break Elongation % 15 – 45
Yield Elongation %
Izod Unnotched kJ / m2 No breaking
Electrical Properties
Dielectric Strength V/mm x 104 2.5 – 3.3
Volume Resistivity Ohm-cm
Dielectric Constant @ 1 MHz 2.8 – 3.3
Dissipation Factor @ 1 MHz 0.001 – 0.005
Other Properties
Mold Shrinkage % 1.0 – 1.3
Processing Temperature °C 370 – 400
Water Absorption, 24 hr. Immersion % 0.05 – 0.2

Applications

Aerospace: Engine parts, interior parts to rescue gas and smoke emission, exterior parts for good rain erosion properties, and wear and tear resistance.

Healthcare: dental syringes, mechanical limbs, sterile boxes, load-bearing implants, teeth, etc.

Electronics: essential interior and exterior parts for mobile phones, laptops, PCs, washing machines, refrigerators, electronic variables, ACs,

Apart from these, PEEK materials are also heavily making their marks in FMCG, chemicals, hospitality, transportation & logistics, and packaging.

HDPE

HDPE belonging to the polyethylene family of thermoplastics is also known for its reliable chemical and corrosion resistance. Other salient properties are high melting point, excellent impact strength, outstanding tensile strength, and low cost. Its low moisture absorption capabilities also add to its chemical resistance abilities increasing a product’s defense against chemical absorption.

Although high in strength and stiffness, fabricating and molding HDPE into complex shapes is relatively easy. It is considered a high-grade plastic material that applies to many high-end engineering applications. It has an incredible strength-to-density ratio of 0.93 to 0.97 g. When observed under a microscope, HDPE molecular structure differs from LDPE. It has a linear system with little branching, which results in a more robust molecular structure and greater tensile strength. That’s why a 60-gram HDPE cup can hold about a gallon of liquid without bending.

General properties of HDPE:

Property Unit Value
Physical 
Melting Point °C 126 – 135
Coefficient of Thermal Expansion x 10-5
cm / (cm °C) 12.5 – 18.0
Density g mL-1 0.955 – 0.961
Heat Deflection Temperature, 0.5 MPa
°C 64 – 77
Heat Deflection Temperature, 1.8 MPa (unannealed)
°C 76.5 – 78
55 – 67
Mechanical
Tensile Strength, Yield at 23 C
MPa 23.0 – 29.5
Tensile Strength, Break at 23 C
MPa 30.5 – 33
Tensile Modulus at 23 C
MPa 900 – 1550
Flexural Modulus MPa 970- 1380
Flexural Strength, Yield
MPa
Izod Notched J/m (kJ/m2) 71 – 159 (20)
Electrical Properties
Dielectric Strength
V/mm x 104 2.1 – 3.5
Dielectric Constant @ 1 MHz
2.2 – 2.4
Volume Resistivity
Ohm-cm 6 x 1015
Dissipation Factor @ 1 MHz
0.0001 – 0.0005
Other Properties
Continuous Service Temperature
°C -73 – 82
Water Absorption, 24 hr. Immersion
% 0.01 – 0.03
Linear Mold Shrinkage
cm/cm MPa

Applications

Consumer Goods: dustbins, food packaging, trays, kitchen wares, etc.

Fibers & textiles: fabrics, fishing and sports net, ropes, industrial & decorative fabrics

Pipes: industrial, residential, drainage, cable protection, gas, water, large inspection chambers, sea downspout, etc.

Packaging: jerry cans, bulk containers, fruit juices, crates, bottles for storing liquids, etc.

Polypropylene

Polypropylene is one of the most popular and most utilized thermoplastics worldwide. It is resistant to chemicals like diluted acids, alcohol, and bases – comparatively lower but good resistance to ketones, esters, hydrocarbons, and aldehydes. The thermoplastic is also rigid, durable, and highly flammable but is formidable according to different applications.

The low melting point of 120°C might make you less interested in utilizing PP for your next project. All things considered, polypropylene’s chemical-resistant capabilities are still awe-inspiring.

Injection molding is the most suitable fabrication technique for PP.

Property Value
Impact Strength
2 – 6 kJ/m2 at 20 °C
Density
1.04 – 1.06 g/cm3
Melting Point 160-168°C
Elastic Modulus 1.5 – 3 GPa
Thermal Conductivity
0.41 W/(m.K) at 20 °C
Flammability UL 94 HB
Electrical Resistance
1*1013 – 1*1014 Ω.m at 20 °C
Dielectric constant 2.8 at 20 °C
Specific heat capacity
1520 J/(kg.K) at 20 °C
Max. service temperature (short) 140°C
Coefficient of thermal expansion
6*10-5 – 1*10-4 1/K at 20 °C

Applications

Automotive: door trims, instrumental panels, fender lines, battery cases, trays, boxes, etc.

Medical: medical syringes, specimen bottles, food trays, medical vials, diagnostic devices, pill containers, pans, Petri dishes, etc.

Consumer goods: toys, luggage, furniture, and packaging for food materials like veggies, meat, and eggs.

Industrial: tanks, sheets, and pipes.

Fibers & fabrics: staple fibers, strapping, tapes, staple fibers, spun-bond, etc.

Engaging Read – What are the Top 5 High Tensile Strength Plastics?

PVC

PVC is a rigid and tough plastic mostly utilized in piping applications. It is easy to fabricate and effortlessly bonds with solvents and adhesives. PVC has outstanding joining capabilities, making it a prime choice for manufacturing valves and fittings. Since it is used extensively in piping applications (often in harsh environmental conditions), engineers have been able to enhance PVC’s chemical resistance abilities over the period.

PVC is inexpensive and comes in many grades and colors, giving engineers the necessary freedom. Although PVC is malleable, it’s not easy to fabricate it in injection molding.

Applications

  • Plasticized PVC is utilized in indoor house flooring, and unplasticized PVC is utilized in making window frames.
  • Residential and sewage pipes.
  • Insulation on electrical wires.
  • Garden hose and imitation leather upholstery.
  • PVC fabric is utilized in the manufacture of raincoats, aprons, jackets, shower curtains, and sports bags.

PVDF

PVDF or Polyvinylidene Fluoride is a semi-crystalline, tough, inert, and chemically stable thermoplastic fluoropolymer. It boasts excellent chemical resistance, good thermal properties, great radiation resistance, and high crystallinity. It has a good tensile modulus but lags behind in impact strength. It is non-flammable and has decent UV resistance.

PVDF partially shows great resistance to organic acids, aliphatic and aromatic hydrocarbons, alcohols, and halogenated solvents. However, it can also be readily attacked by strong bases and ketones.

PVDF material is easily available in different grades and forms, such as powder and granules. It can be effortlessly fabricated in traditional processing methods like injection molding, extrusions, and compression.

Properties Values Units
Processing Temprature -220°C
Tensile Strength @23°C 50
Mpa – ASTM – D638
Thermal Conductivity@23°C 0.2
W/m.k – ASTM C177
Impact Strength No Break
Melting Point 338-347 deg F
Dielectric Strength 20-25@ 1mm thick
kV.mm – ASTM D149
Elongation at Break @23°C 0.4 ASTM-D1894
Continues working temperature 150 °C
Weathering resistance Excellent
Coefficient of friction 0.4 ASTM-D1894
Limiting Oxygen Index 44 %

Applications

Electrical & Electronics: wires and cables in aircraft, high-temperature wirings, home appliances, and industrial power control systems.

Industrial Applications: gaskets, seals, linings, etc.

Apart from that…

  • PVDF is also utilized for making separators in lithium-ion batteries thanks to reliable thermal and chemical stability.
  • Filtration equipment like housings, filters, membranes, etc
  • Flexible tubing and liners to be used in water systems, pipes of chemicals, automobile fuel lines, and storage.

Thus were the most reliable and mainstream chemical resistant plastic materials. I think any manufacturer choosing from them will ultimately depend on the application. Other mainstream plastics with reputable chemical resistance properties are polycarbonate, UHMW, PET, ABS, PETG, and polystyrene.

FAQs 

Below are the frequently asked questions on the chemical resistance of plastics. Let’s dig deep to find more.

What makes a polymer chemical resistant?

The main factors behind a polymer’s chemical resistance are the polymer’s molecular structure, the type of additives, mechanical load, exposure duration, solvent concentration, chemical reagent, and temperature fluctuations.

How chemical resistant is polycarbonate? 

Polycarbonate is resistant to many organic acids, minerals, neutral and acid salt solutions, oxidizing and reducing agents, oils, waxes, greases, saturated, aliphatic, and cycloaliphatic hydrocarbons, and alcohols, except for methyl alcohol.

How chemical resistant is PET?

PET is a strong, dimensionally stable polymer with reliable chemical resistance and wears & tear properties. It boasts excellent machining capabilities with outstanding strength, stiffness, and chemical resistance. However, If I had to list the seven best chemical-resistant plastics, I would’ve put PET in the 7th spot, but I think The six listed materials are enough for any manufacturer.

How chemical resistant is UHMW?

UHMW is generally known for its extraordinary toughness and outstanding wear and tear resistance. It also boasts good chemical resistance and is useful in many industrial applications requiring low friction, durability, and reliable chemical resistance.

How chemical resistant is ABS?

ABS material is resistant to many chemicals and acids like alkalis, aqueous acids, concentrated hydrochloric and phosphoric acids, and animal, vegetable, and mineral oils but is attacked by glacial acetic acid, carbon tetrachloride, aromatic hydrocarbons, concentrated sulfuric and nitric acids.

Suggested Read 

Final Thoughts 

To sum up, the utilization of chemical resistant plastics plays a crucial role in industries that deal with harsh chemicals. The article has presented six of the widely used chemical-resistant plastics, such as PTFE, PVC, PVDF, PEEK, HDPE, and Polypropylene, along with their distinctive properties and applications.

Having a good understanding of these materials can aid in making an informed decision when selecting suitable plastic for your project. By selecting the appropriate chemical-resistant plastic, you can ensure your workers’ safety, enhance your equipment’s durability, and improve your operational efficiency.

That is all I want to say about Top chemical resistant plastic materials. Always consulting your material supplier is a great practice in choosing the best polymer for your project. Chemical ineffectiveness is essential for industrial applications, especially those with real-world applications in harsh environmental conditions.

Thanks for reading. Have a lovely day.

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