The material used in this investigation is a commercially
available PTFE (DuPont Teflon), which is characterized by
a density of 2.18 103 kg/m3 and a melting temperature
about 327 C.
The standard tension test specimens were manufactured
from PTFE with shape and size specified by ASTM D-
638-08 (Type I) [26]. The initial gage length l0 and initial
cross section A0 are, respectively, 50 mm and 26 mm2
(13 mm 2 mm) as illustrated in Fig