Polymethylpentene is classified as a polyolefin and is a high-molecular weight hydrocarbon. Polymethylpentene is similar to polypropylene, but has an isobutyl group instead of a methyl group attached to each monomer group of the chain. Its chemical resistance is close to that of PP. It is more easily softened by unsaturated and aromatic hydrocarbons, and chlorinated solvents.
PMP is slightly more susceptible than PP to attack by oxidizing agents. Like all polyolefins, polymethylpentene is non-toxic, non-contaminating and lighter than water. Its excellent transparency, rigidity and resistance to chemicals and high temperatures make PMP a superior material for labware.
PMP withstands repeated autoclaving. It can withstand intermittent exposure to temperatures as high as 175°C. Products made of polymethylpentene are brittle at ambient temperature and may crack or break if dropped from benchtop height.
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Polymethylpentene is used to make a variety of Nalgene labware where visual clarity is valued in addition to shatter resistance, autoclavability, and chemical compatibility.
Popular products made from polymethylpentene (PMP or TPX)
Physical properties
Temperature | Physics | Permeability | Sterilization[4] | Regulatory |
 |  |  |  |  |
HDT[1]: 82℃–90℃ Max Use[2]: 153℃–174℃ Brittleness[12]: 0℃–20℃ | UV light: fair resistance Rigid Transparent Microwaveable[13]: yes Specific gravity: 0.835 | cc.-mil/ 100in2-24hr.-atm
N2: 8,000
O2: 32,000
CO2: 115,000 cc.-mm/ m2-24 hr.-Bar
N2: 3,108
O2: 12,434
CO2: 44,684 | Autoclave: yes EtO: yes Dry heat: no Radiation: marginal Disinfectants: yes | Non-cytotoxic[6]: yes Suitable for food & bev use[7]: yes[14] Regulation Part 21 CFR: 177.1520 |
Chemical compatibility
The following table contains general use exposure ratings at 20°C. The ability of plastic materials to resist chemical attack and damage is also dependent 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.
| Class | General rating |
| Acids, dilute or weak | E |
| Acids*, strong and concentrated | E |
| Alcohols, aliphatic | E |
| Aldehydes | G |
| Bases/alkali | E |
| Esters | E |
| Hydrocarbons, aliphatic | G |
| Hydrocarbons, aromatic | N |
| Hydrocarbons, halogenated | N |
| Ketones, aromatic | F |
| Oxidizing agents, strong | G |
*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. |
Nalgene products made from polymethylpentene (PMP or TPX)
Application tips for Nalgene PMP products
Polymethylpentene labware and containers are autoclavable. The recommended autoclave cycle for empty containers is 121°C at 15 psi for 20 minutes. Note: while PMP graduated cylinders and volumetric flasks are autoclavable, autoclaving will affect measurement accuracy.
Autoclaving
Care must be taken to allow free air circulation into and out of containers 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 containers with caps, 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.
Be sure to follow all autoclave instructions provided with your PMP labware products or contact Nalgene technical support for detailed autoclave instructions for your specific products.
Plastic aging
PMP labware will age over time. If labware pieces are significantly discolored (yellow, brown, 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 PMP 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.
Footnotes:
[1]. 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.
[2]. 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.
[3]. The plastic will absorb and retain significant amounts of heat resulting in an unexpectedly hot surface.
[4]. 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 before hand.
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.
[6]. “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.
[7]. 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.
[12]. 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.
[13]. 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.
[14]. Straight-sided jars, beakers, and graduated cylinders only.
Technical support
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 technicalsupport@thermofisher.com.
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 techsupport.labproducts.eu@thermofisher.com.
Regulatory support: for regulatory documentation of product or material claims, please contact Nalgene regulatory support at RocRegSupport@thermofisher.com.
Resources
Request printed resources
- Break the Glass Habit Brochure
- Bottle and Carboy Selection Guide
- Plastic Properties Reference Magnet
- Plastic Labware Chemical Resistance Wall Poster
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