Like the polyethylenes, polypropylene is classified as a polyolefin and is a high-molecular weight hydrocarbon. Polypropylene’s chemical structure is similar to polyethylene, but each unit of the chain has a methyl group attached. Like all polyolefins, polypropylene is non-toxic, non-contaminating and lighter than water.
PP is naturally milky white translucent in color, though colorants may be added to make the material opaque and a variety of colors. It is autoclavable and has no known solvent at room temperature.
PP is slightly more susceptible than the polyethylenes to strong oxidizing agents. It offers the best stress-crack resistance of the polyolefins. Products made of polypropylene are brittle at 0°C and may crack or break if dropped from benchtop height. PP can be damaged by long-term exposure to UV light.
Polypropylene in its homopolymer form is used to make products where strength, autoclavability, and stress-crack resistance are needed such as carboys, autoclave baskets, and vacuum flasks. Most Nalgene bottle closures (caps) are made from polypropylene regardless of the bottle material because PP provides the necessary stress-crack resistance while the ideal seal is achieved by mating caps and containers of un-like materials.
Max Use: 130℃
UV light: fair resistance
Specific gravity: 0.90
cc.-mm/ m2-24 hr.-Bar
Dry heat: no.
Radiation: no discoloration & embrittlement unless stabilized
Suitable for food & bev use: yes
Regulation Part 21 CFR: 177.1520
The following table contains general use exposure ratings at 20°C. The ability of plastic materials to resist chemical attack and damage is dependent also on temperature, length of exposure to the chemical, and added stresses such as centrifugation. For more detailed chemical resistance ratings for Nalgene products and materials, please consult the resources referenced at the bottom of this page.
|Acids, dilute or weak||E|
|Acids*, strong and concentrated||G|
|Oxidizing agents, strong||F|
*Except for oxidizing acids; for oxidizing acids, see "Oxidizing agents, strong."
|E||30 days of constant exposure causes no damage. Plastic may even tolerate for years.|
|G||Little or no damage after 30 days of constant exposure to the reagent.|
|F||Some effect after 7 days of constant exposure to the reagent. Depending on the plastic, the effect may be crazing, cracking, loss of strength, or discoloration.|
|N||Not recommended for continuous use. Immediate damage may occur including severe crazing, cracking, loss of strength, discoloration, deformation, dissolution, or permeation loss.|
Homopolymer or copolymer?
Nalgene manufacturing historically used the term “polypropylene” generically to mean either the homopolymer form (discussed here) or the copolymer form (PPCO) which is used to make most Nalgene labware products like bottles, beakers, cylinders, and other general labware items. While the resin code is molded into or printed on many products, one cannot faithfully distinguish between PP in its homopolymer form and PPCO when the resin code “PP” is found on the product. It could be either material. Many polypropylene copolymer products have “PP” resin codes on them. The best way to determine if a product is PP or PPCO is to follow the product links on these plastic material pages or for critical applications, contact Nalgene technical support.
Polypropylene containers are autoclavable. The recommended autoclave cycle for empty containers is 121°C at 15 psi for 20 minutes. Care must be taken to allow free air circulation into and out of vessels during the autoclave cycle, especially during the venting and cooling stages. If the container is not properly vented, collapse or implosion (sometimes confused with melting) can occur. When autoclaving bottles and carboys, the cap threads must be completely disengaged from the container; the cap can be set loosely over the mouth opening at a rogue angle to ensure the threads don’t inadvertently engage. Once the container is completely cooled, the cap can be aseptically tipped into place and tightened down.
PP labware will age over time. If labware pieces are permanently discolored (yellow, brown, pink, etc.), if you see cracks or spiderweb-like “crazing” beginning to occur, it’s probably time to replace your old labware. Repeated autoclaving will accelerate the aging process and necessitate more frequent replacement. To slow the aging process and prolong the life of your PP labware, store products in a cabinet out of direct exposure with UV light (including overhead indoor lighting), use only with compatible chemicals, and wash with a pH-neutral detergent like Nalgene L900.
PP products are recyclable in many communities (recycle code 5). Most Nalgene PP products are reusable and will last a long time under typical lab conditions if used appropriately, but you can recycle them at the end of their lifetime as long as they are thoroughly cleaned for safe handling.
. Heat Deflection Temperature is the temperature at which an injection molded bar deflects 0.1” when placed under 66 psig (ASTM D648) of pressure. Materials may be used above Heat Deflection Temperatures in non-stress applications; see Max. Use Temp.
. Max. Use Temp. °C: this is related to the maximum continuous use temperature, ductile/brittle temperature and glass transition temperature and represents the highest temperature at which the polymer can be exposed for the matter of minutes to 2 hours where there is little or no loss of strength.
. The plastic will absorb and retain significant amounts of heat resulting in an unexpectedly hot surface.
. STERILIZATION: Autoclaving (121° C, 15 psig for 20 minutes)—clean and rinse items with distilled water before autoclaving. (Always completely disengage thread before autoclaving.) Certain chemicals which have no appreciable effect on resins at room temperature may cause deterioration at autoclaving temperatures unless removed with distilled water beforehand.
EtO Gas—Ethylene Oxide: 100% EtO, EtO:Nitrogen mixture, EtO:HCFC mixture
Dry Heat—exposure to 160°C for 120 minutes without stress/load on the polymer parts
Disinfectants—Benzalkonium chloride, formalin/formaldehyde, hydrogen peroxide, ethanol, etc.
Radiation—gamma or beta irradiation at 25 kGy (2.5 MRad) with unstabilized plastic.
. “Yes” indicates the resin has been determined to be non-cytotoxic, based on USP and ASTM biocompatibility testing standards utilizing an MEM elution technique with WI38 human diploid lung cell line.
. Resins meet requirements of CFR21 section of Food Additives Amendment of the Federal Food and Drug Act. End users are responsible for validation of compliance for specific containers used in conjunction with their particular applications.
. The brittleness temperature is the temperature at which an item made from the resin may break or cracked if dropped. This is not the lowest use temperature if care is exercised in use and handling.
. Ratings based on 5-minute tests using 600 watts of power on exposed, empty labware. CAUTION: Do not exceed Max. Use Temp., or expose labware to chemicals which heating will cause to attack the plastic or be rapidly absorbed.
For assistance choosing products appropriate for your application, please speak with a Nalgene technical support representative team by phone at +1-585-586-8800 or (1-800-625-4327 US toll free), or email your request to firstname.lastname@example.org.
In Austria, France, Germany, Ireland, Switzerland, and the United Kingdom please contact technical support by phone at +800-1234-9696 (toll free) or +49-6184-90-6321, or email your request to email@example.com.
Regulatory support: for regulatory documentation of product or material claims, please contact Nalgene regulatory support at RocRegSupport@thermofisher.com.
For chemical compatibility ratings by chemical, temperature, and length of exposure, use the Nalgene General Labware Chemical Compatibility Guide
For centrifugeware chemical compatibility ratings, please use ONLY the Centrifuge Ware Chemical Resistance
California Proposition 65 Warning: Products manufactured with polycarbonate (PC), polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG) or polystyrene (PS) contain chemicals known to the State of California to cause cancer, birth defects or other reproductive harm.