Search
| Books | New Products | Special Issues | Sample Articles | For Authors | Supplier Info
 
 
 

 

Article Abstracts

Published:Journal of Chromatographic Science, ISSN 0021-9665 Volume 45, Number 8, September 2007, pp. 524-530

Molecular Weight Distributions of Industrially-Produced Poly-(e-Caprolactams) by Gel Permeation Chromatography

Elena Mateos[1], Vicente L. Cebolla[1], Luis Membrado[1], Elena Piera[2], and Miguel A. Caballero[2]
[1]Instituto de Carboquímica, CSIC. P.O. Box 549, 50080 Zaragoza, Spain and
[2]NUREL, S.A., Carretera de Barcelona, km 329, Polígono de Malpica, 50016, Zaragoza, Spain

Gel permeation chromatography with differential refractometry is used to obtain molecular weight distributions (MWD) of poly-(e-caprolactams). Elution is carried out using an m-cresol– chlorobenzene mixture (50:50, v/v) at 50°C. MW values are obtained by a Hamielec-based calibration method, using broad-MWD poly-(e-caprolactam) standards with the same chemical nature and similar MWD to the samples. Relative errors for the number-average MW (Mn) using this calibration method range from 0.4% (in the low polyamide MW range) to 20% (in the high polyamide MW range). These values are much lower than those obtained from narrow-MWD polystyrene calibration, which range from 39% to 78%. Similar values have been obtained for the other usual average MW parameters. The ability to obtain repeatability parameters for a given confidence interval and the utilization of statistical criteria for chromatogram rejection allow this method to be used in quality control for MWD of poly-(e-caprolactams). Thus, production variables are related to polyamide-6 behavior in its ulterior treatment. Typical relative standard deviation percentages (for n = 6) of a polyamide sample range from 1.9% (for Mn) to 3.3% (for Mz + 1).

Reproduction of editorial content of this journal is prohibited without publisher’s permission.

This article is available in its entirety by fax for $4.00 per page.
Visa or MasterCard accepted.

To order electronically click here
or call: 847-647-2900 ext. 1323
or fax request to: 847-647-1155.

Please indicate JCS volume and issue along with page numbers.

Site Map: Home | Current Issue | Subscribe | Back Issues | About Us | Meetings | Advertising |
| Books for Sale | For the Author | Links | Supplier Info | Search |