Ultra high molecular weight polyethylene (UHMW/PE) has an average molecular weight greater than 3,100,000 as defined by ASTM D4020 standards for UHMW/PE. UHMW/PE is a linear polyolefin that is made up extremely long chains of polyethylene, which all align in the same direction. Commercially offered resins are available from 3-6 million molecular weight, with resins in the 3.1-4.5 range having the best combination of impact strength and abrasion resistance. The molecular weight of UHMW/PE must be approximated using the solution viscosity procedure found in ASTM D4020. There are several different trade names for UHMW/PE throughout the industry. Our proprietary trade name is “Ultrex”.
UHMW/PE has a unique characteristic of thermal expansion/contraction. The colder the application, UHMW/PE will contract. The warmer the application, UHMW/PE will expand. Spiratex cuts and ships their UHMW/PE parts based on the tolerances and length of the part at 72F. The equation to determine the amount of thermal expansion/contraction is as follows:
.00011 x inches long x temperature change from 72F.
For example a part that is 240 inches long at 100F will grow by .74”.
Excellent abrasion resistance
The highest impact strength of any thermoplastic
Superior chemical resistance, even to the most aggressive chemicals, including better chemical resistance than HDPE, P/U, steel and nylon
Water repellent and highly-resistant to hydrolysis
Excellent dielectric and insulating properties
Frequent applications include:
Material handling, including food contact surfaces, since it is acceptable under FDA and USDA guidelines
Lead-acid battery separators
A wide variety of other applications