Geoysynthetics August/September 2023 - 41

and needs to be diluted in very hot water
before entering the stress cracking bath,
which brings into question its viability as
a replacement surfactant from a handling
perspective. In addition, Dehyton did not
shorten the time horizon for the stress
crack test when at an elevated temperature
of 70°C. It should be noted that testing
at elevated temperatures has drawbacks,
such as it is harder to control and
maintain bath temperature. In addition,
elevated temperatures present challenges
such as accelerated corrosion over time.
To our knowledge, all known substitute
surfactants tested to date have unique
characteristics that will affect stress cracking
in HDPE geomembranes differently.
Unfortunately, we know of no REACHcompliant
surfactant that has the same
SP-NCTL signature as Igepal CO-630
to use with polyethylene geomembranes
common to our industry. After extensive
round-robin testing, it has been determined
that no known REACH directive
compliant surfactant has the exact equivalent
efficacy of Igepal CO-630.
Therefore, if performing this test with
a substitute-alternative surfactant, one
will have to first determine a correlation
between the substitute-alternative surfactant
and Igepal CO-630. Comparative
experiments will have to show the following
for validation:
* a correlation coefficient greater
than 0.9,
* a coefficient of variation within any
given SP-NCTL data set of less than
5, and
* a specimen set of at least 30 data points.
Upon satisfying all the above requirements,
an effectiveness ratio may be used
to extrapolate results between the substitute-alternative
surfactant and Igepal
GM
Number
GM-71
GM-72
GM-73
GM-74
GM-75
Igepal
3+/-2
165 +/- 24
>500
375 +/- 67
>1,000
Rhodasurf
14+/-13
470 +/- 250
487 +/- 220
>500
>1,000
Tergitol
4+/-4
464 +/- 336
557 +/- 318
489 +/- 275
418 +/- 375
TABLE 1 Summary of round-robin results (all results in units of hours)
CO-630. It should be clearly stated that
this ratio is only good for the actual
HDPE formulation being tested and not
all geomembrane types.
We would sincerely like to thank the
GSI consortium for their continued support
and sponsorship. In addition, we
would like to thank our participating
round-robin laboratories for their expertise
and collaboration. It truly takes a
village to move forward with the work
presented. Testing results were received
from the following laboratories:
* AGRU America, Georgetown,
S.C., USA
* Atarfil Europe Geomembranes,
Granada, Spain
* Drexel University, Philadelphia,
Pa., USA
* Geosynthetic Research Institute
(GSI), Folsom, Pa., USA
* Layfield Canada Ltd., Concord,
Ont., Canada
* NAUE GmbH & Co. KG,
Espelkamp, Germany
* SAGEOS Group CTT, SaintHyacinthe,
Que., Canada
* SKZ, Wurzburg, Germany
* SOLMAX, Varennes, Que., Canada
* TRI Environmental Inc. Austin,
Texas, USA G
GeosyntheticsMagazine.com
41
Dehyton
7+/-6
>500
>500
766 +/- 156
>1,000
>> For more, search GSI at
GeosyntheticsMagazine.com.
http://www.GeosyntheticsMagazine.com http://www.GeosyntheticsMagazine.com
Geoysynthetics August/September 2023

Table of Contents for the Digital Edition of Geoysynthetics August/September 2023
