tensile stress failing thereby the material film before the seal.
Maximum tensile resistance was 1.6 ? 0.3 MPa, being this value
closer to the maximum strength of TPS films determined by the
aforementioned tensile test (Table 1). The fact that both values
were similar regardless different crosshead speed used in tensile
tests is an indicative that TPS films material failed before the seal.
On the other hand, film juncture of TPS composite with 5% w/w talc
nanoparticles failed before material breakage. This result is in
accordance with TPS matrix reinforcement by talc addition,
demonstrated through tensile and quasi-static tests (Fig. 1 and
Table 1). For these composite films the involved energy to cause
adhesive-cohesive seal failure was 19.1 ?1.7 J/m. Moreover, average
thermo-sealing resistance of composite films was 1.7 ? 0.1 MPa.
The fact that this value resulted significantly lower than the
maximum tensile strength obtained by tensile tests (Table 1)
demonstrates that seal was less resistant than film material. In
addition, talc incorporation to TPS matrix increased the resistance
around 11% to cause specimen failure, regardless the breakage
mode. SEM observations of the seal zone of tested specimens were
carried out in order to analyze if failure of TPS films with 5% w/w
talc corresponded to an adhesive or a cohesive mode. Fig. 3 pre-
sents SEM micrographs corresponding to both films which were in
contact before tensile tests. Fig. 3A and B are like specular images
between them. When seal was opened, part of the material cor-
responding to one of the films was pulled out, causing a cohesive
failure mode. Resulting hollows due to the material pulling are
indicated with arrows in Fig. 3A. On the other hand, in Fig. 3B are