Journal Published Online: 27 December 2021
Volume 45, Issue 2

Polymer Quantification Methods for Geosynthetic Clay Liners Enhanced with Anionic Polymers



Two methods of quantifying the amount of anionic polymer in enhanced bentonites (EBs), total carbon (TC) and loss on ignition (LOI), and several procedures were evaluated. Both methods can be applied to EBs comprising sodium bentonite (NaB) and a polymer. The composite procedure requires the use of a calibration curve created via measurement of the same EBs at varying known polymer contents. The component procedure separates the measurements of the NaB and polymer comprising the EB. The procedures evaluated included component LOI, composite TC, and two component TC procedures, one that measured only TC (component A TC) and another that measured both TC and total inorganic carbon (component B TC). The EBs evaluated included NaB enhanced with one of several anionic polymers, including low-, medium-, and high-molecular-weight poly(acrylic acid), low- and high-viscosity sodium carboxymethyl cellulose, and covalently crosslinked sodium polyacrylate. Polymer contents of geosynthetic clay liners (GCLs) containing EBs after permeation with 500 mM sodium chloride (NaCl) or 167 mM calcium chloride (CaCl2) also were determined, and the results from the different procedures were compared. The component LOI procedure underestimated the actual polymer content of EB regardless of specimen mass or polymer type. The polymer content of nonhydrated EB-GCLs was measured within ±0.1 % (error ≤ ±6.0 %) using the composite TC procedure, corroborating the usefulness of this procedure for determining the polymer content of the EBs in pre-permeated EB-GCLs. The polymer loading of nonhydrated EBs in EB-GCLs also was measured within ±0.3 % (error ≤ ±6.4 %) using the component A TC procedure. In post-permeated EB-GCLs, the composite and component A TC procedures resulted in final polymer contents similar to those for the component B TC procedure (within 0.4–0.8 %). Thus, all three TC procedures were viable for quantifying the polymer content of the post-permeated EB-GCLs.

Author Information

Norris, Anna
Stantec Inc., Denver, CO, USA
Scalia, Joseph
Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA
Shackelford, Charles D.
Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA
Pages: 17
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Stock #: GTJ20210134
ISSN: 0149-6115
DOI: 10.1520/GTJ20210134