Peel strength.
Peel strength was determined by means of a T-peel method modified from the ASTM
D1876 [8] using transparent polyvinyl chloride sheet as substrate. Measurement of the force required to
peel specimen away from transparent sheet was performed by using an Instron testing machine with a
500N loaded cell which the size of film specimens was 10 u 60 mm2
. The cross-head speed was
controlled at 300 mm/min dwell time.