EFFECT OF GAMMA IRRADIATION ON THE DEGREE OF CROSSLINKING OF TPS/PBAT BIODEGRADABLE POLYMER FILMS FROM THERMOPLASTIC STARCH (TPS) AND POLYBUTYLENE ADIPATE TEREPHTHALATE (PBAT)

Abstract

Tapioca starch is an available and rich source of material in Viet Nam, low-cost and biodegradable.
However, it is necessary to modify the starch into thermoplastic starch before blending it with other
biodegradable polymers. In this research, thermoplastic starch was synthesized from Tapioca starch with
Glycerol and Ethylene Glycol; TWEEN 80. The FT-IR spectrum shows that Glycerol and Ethylene Glycol
plasticizers mix well with starch and don’t change the structure of the starch. The TGA spectrum of starch
and thermoplastic starch shows that thermoplastic starch synthesized is a homogeneous plastic. TPS has
been blended with biodegradable polymer Polybutylene adipate terephthalate (PBAT) to make TPS/PBAT
polymer films. The films were irradiated with doses of 10, 20, 40, 50, 60 and 100 kGy. Gel fraction
measurements of the TPS/PBAT film before and after irradiation showed that the degree of crosslinking in
the TPS with PBAT increased with the increased irradiation doses. The highest gel fraction of the film was
80.2% when irradiated with a dose of 100 kGy. The degradation test with the alpha-amalyse enzyme
showed the TPS/PBAT polymer film lost approximately 54% of its weight after 14 days.