Maleated thermoplastic starch was produced in a Century
CX-30 co-rotating twin-screw extruder. Maleic anhydride
was ground into a fine powder using a mortar and pestle,
pre-blended with the corn starch, and placed in the external
feeder, which fed into the feed port of the extruder. Luperox
101 was pumped into the feed throat of the extruder using a
peristaltic pump. Glycerol, which was warmed in a water
bath of boiling water, was also pumped into the extruder
using a peristaltic pump. The extruder was electrically
heated and the maximum temperature of the extruder was
set to 165 C, with a temperature profile of 25/95/125/145/
160/165/165/165/150/145 C from the feed throat to the
die. Cooling water was circulated through the extruder in
order to maintain the set temperatures during the extrusion
process. The feed rates of the external feeder containing the
starch and the peristaltic pump for the glycerol were set so
as to accomplish a composition of 80 wt% starch and
Copolyester
C C
O O
O CH2 O C
O
CH2 C
O
m n
x y z
Terephthalic acid Diol Aliphatic diacid
Fig. 1 Chemical structure of poly(butylene adipate-co-terephthalate)
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