ASTM Committee E15 on Industrial and Specialty Chemicals is seeking glycol producers and users to participate in an interlaboratory study to determine the precision and bias for ASTM E 2193, Standard Test Method for Ultraviolet Transmittance of Monoethylene Glycol (Ultraviolet Spectrophotometric Method). To participate, contact Passwater at 281/544- 6740.

A standardization consultant and two chemists working with stakeholders in ASTM Subcommittee E15.02 on Product Standards based new ASTM E 2193 on an original Shell Chemical method that determines the transmittance of monoethylene glycol (1,2-ethanediol; MEG) at wavelengths in the region 220 to 350 nm, says Deborah K. Passwater, chemist, EO/Glycols, Shell Chemical LP, Houston, Texas. The original method had been used internally at Shell for many years, Passwater says. When industry members wanted a uniform industry method for ultraviolet transmittance of monoethylene glycol, they presented the Shell method to ASTM to be developed through voluntary consensus. The Society reviewed the Shell method, and approved it as new ASTM Standard E 2193 on March 10.

“Most polyester fiber grade MEG producers and users have specifications that require a minimum UV transmittance value,” explains Passwater. “The methods currently used in the industry are inconsistent across both producers and users. The ASTM E 2193-02 standard UV method will provide a consistent industrial method that can be utilized and referenced by all.

“Monoethylene glycol is an extensively used industrial feed stock for polyester production, including polyethylene terephthalate (PET) plastics,” continues Passwater. “UV measures the presence of compounds in MEG that absorb light in the ultraviolet region of the spectrum. These undesirable compounds are in trace quantities in the ppb ranges and primarily unknown in chemical structure. Thus, they cannot be measured directly. UV is measured extensively during the glycol production process, product release and product acceptance.

“Ultraviolet transmittance is one of the most important quality parameters that have impact on the polyester product quality,” she concludes. “Glycol that has poor or low UV transmittance can negatively impact the appearance of the final product.”

To participate in the interlab study, contact Deborah K. Passwater, Shell Chemical LP, Houston, Texas (phone: 281/544-6740). Committee E15 meets Oct 7-8 in Jackson Hole, Wyo. For meeting or membership details, contact Diane Rehiel, manager, ASTM Technical Committee Operations (phone: 610/ 832-9717). //

Copyright 2002, ASTM