The mechanical properties of the films were studied by characterising
the tensile strength (TS), elongation at break (EAB) and
elastic modulus (E). TS is expressed as the maximum force at break
per initial cross-sectional area of the film and the elongation as a
percentage of the original length; this is the maximum tensile
stress that the film can sustain. EAB is the maximum change in
length of a test specimen before breaking, while E is a measure of
the stiffness of the film.