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Chemical Resistance of Thermoplastics - Fingertips Facts
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Chemical Resistance of Thermoplastics - Fingertips Facts
Again the rules of thumb to ease out the hell life of plant engineers...
Chemical resistance of selected commercial thermoplastics and elastomers
References
1. “Perry’s Chemical Engineers’ Handbook: 8th ed.” McGraw Hill, New York, 2008.
2. Nibco Chemical Resistance Guide. Nibco Inc. Elkhart, Ind. 2003.
3. Plastics Pipe Institute. Chemical Resistance of Thermoplastics. Techincal Report 19. 2007.
Corrosion is estimated to account for a significant portion — 8–10% — of total annual-plant-capital expenditures for the chemical process industries. To avoid it, engineers can consider corrosion-resistant plastics for process piping and storage vessels. Thermoplastics are generally resistant to chemical attack and thus suitable for many process applications. However, plastics must be selected based on process specifics. When chemicals affect plastics, it usually happens as: chemical solvation or permeation, where physical properties may change, but the polymer molecular structure is not chemically altered; and direct chemical attack, where a a chemical reaction with the polymer occurs.
Chemical resistance of selected commercial thermoplastics and elastomers
Name | Notes | Recommended Uses | Uses to Avoid |
ABS (acrylonitrile butadiene styrene) | Smooth inner surface and resistance to deposit formation Resistant to a wide variety of materials up to 65ºC (150°F) | •Commercial sanitary systems •Weak acids | Oxidizing acids |
PVC (polyvinyl chloride) | Most frequently specified of all thermoplastic materials | •Chilled water •Deionized water, irrigation •Salt solutions •Acids •Alkalis | Polar solvents, such as ketones |
CPVC (chlorinated polyvinyl chloride) | Better chemical resistance than PVC | •Hot corrosive liquids •Hot or cold water | Ultraviolet (UV) radiation |
PE (polyethylene) | Lowest-cost commercially available plastic. Pipes generally must be supported | •Ethanol, methanol •Sodium, potassium, calcium hydroxide (30%) •Glycol •Oils, natural gas, gasoline | •Diethylether •Methylene chloride •Ethylene chloride |
PP (polypropylene) | Lightweight polyolefin Can be used at higher temperatures than PE | •Organic solvents •Resistance to sulfur-bearing compounds •Salt-water disposal lines •Crude-oil piping •Mixtures and acids, bases, solvents | •Strong oxidizing agents •Chlorinated hydrocarbons •Aromatics |
PVDF (polyvinylidene fluoride) | Best combination of strength, chemical resistance and working temperatures | •Wet or dry chlorine, bromine, other halogens •Acids, bases, organic solvents | Fuming sulfuric acid |
EPDM (ethylene propylene diene monomer) | Good abrasion and tear resistance | Variety of acids and bases, alcohols, ketones | •Petroleum oils •Strong acids •Strong bases |
Chlorosulfonated polyethylene (Hypalon) | Good resistance to ozone, flames | Salt solutions, nitric, sulfuric, hydrofluoric acids | Fuming nitric and sulfuric acids |
Neoprene | Among the first synthetic rubbers developed | •Food and beverage applications •Vegetable oils | •Strong oxidizing agents •Chlorinated solvents •Esters •Ketones |
Nitrile | Copolymer of butadiene and acrylonitrile | •Solvent •Oil •Water •Hydraulic fluid | •Highly polar solvents •Chlorinated hydrocarbons |
Polyamide (Nylon) | Hygroscopic material Good abrasion resistance | •Gasoline •Alkanes •Acetone, methylethyl ketone | •Strong oxidizing agents •Phenols •Mineral acids |
Fluorocarbon | Inherently compatible with a wide spectrum of chemicals | •Mineral acids •Salt solutions •Chlorinated hydrocarbons •Petroleum oils | Steam |
Polytetrafluoroethylene (PTFE; Teflon) | Most chemically resistant plastic commercially available | Outstanding resistance to most chemicals and solvents | Molten metals |
PEEK (polyether etherketone) | Can be used at higher temperatures than PTFE; physical characteristics approaching some metal | •Heat transfer fluids •Steam •Hydrocarbons | Concentrated nitric, hydrochloric, hydrobromic, hydrofluoric and sulfuric acids |
Polyethylene teraphthalate (PET) | Shows resistance to ultraviolet radiation | •Hydrocarbon fuels •Water •Ethanol, ethyl ether | •Concentrated sulfuric acid •Phenol •Acetone |
References
1. “Perry’s Chemical Engineers’ Handbook: 8th ed.” McGraw Hill, New York, 2008.
2. Nibco Chemical Resistance Guide. Nibco Inc. Elkhart, Ind. 2003.
3. Plastics Pipe Institute. Chemical Resistance of Thermoplastics. Techincal Report 19. 2007.
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