All of the peel-strength measurements were based on the procedure detailed in ASTM D1876-08 – Standard Test Method for Peel Resistance of Adhesives (T-Peel Test). Because the work reported here involved many hundreds of separate adhesion experiments, however, practical considerations required several modifications to the ASTM-D1876-08 procedure. First, each peel sample was an adhesive-bonded pair of 25 mm-wide strips, consistent with ASTM-1876-08, but those strips were only 6.25 cm long with 3.75 cm of bonded length, rather than the 30.5 cm-long strips with 24.1 cm of bonded length required by ASTM-D1876-08. Secondly, those bound pairs were prepared individually, rather than six at a time in a large sheet, and they were not always allowed to cure or dry for a full week at a controlled humidity.
Lastly, the peel strengths reported here were obtained by measuring and averaging 3 nominally identical samples, rather than the ten samples specified in ASTM-1876-08. Both the average of the peeling force per unit of bond width and its standard deviation during the peel measurement were obtained for each sample and those values were themselves averaged over the 3 nominally identical samples.