Poly(butylene succinate), (PBS) with different molecular weight was gamma -
irradiated at different temperatures and various doses. PBS with high molec
ular weight and smaller peak area of crystal melting gave the highest gel c
ontent at the same temperatures and dose. A two-step irradiation (irradiati
on in molten state after irradiation at room temperature) gave the highest
gel content in different conditions. This is due to the formation of networ
k structure by pre-irradiation at room temperature that leads to less degra
dation. PBS prepared by two step irradiation was effective for improvement
of heat stability because of high gel content formation. Unirradiated PBS s
heets broke immediately at 110 degrees, while the irradiated sample (gel fr
action, 50%) by a two step-method did not break even up to 200 minutes at 1
30 degreesC. The PBS sheets are biodegradable even after crosslinking.