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Durability of a starch-based biodegradable polymer
指導教授:王振乾
學 生 : 陳 雅 貞
日期：2010.09.20
Abstract
 The photo-oxidation and the photo-stabilization of a
commercial biodegradable polymer have been investigated
in order to establish the possibility of using this polymer as
raw material for films for agriculture.
 The bioplastic film must possess specific mechanical and
optical performance similar to those of the traditional films
for agriculture, like polyethylene and poly[ethylene-co(vinyl acetate)].
Materials
 The biodegradable polymer, MB
 non-genetically modified maize starch
 synthetic biodegradable polyester
Materials
Tinuvin 327
UV
Tinuvin
234stabilizers
benzotriazole
Lowilite 22
benzophenone
Tinuvin 1577
Sanduvor PR-31
triazine
HAS
Before processing
 The biodegradable polymer was carefully
dried for 24 h in a ventilated oven at 60 ℃ followed
by 24 h at 60 ℃in a vacuum oven.
Processing
 Stabilized polymer:

The thermal profile was 90-110-135-180 ℃ and the
screw
was set
at 50 rpm.
Thespeed
estimated
residence
time is about 100-150 s.
Unstabilized
polymer: of the films was in the range
The final thickness
250280 μ m.thermal profiles:
two different
90-110-135-150 ℃ and 95-140-165-210 ℃, with the
same screw speed.
Photo-oxidation
 Photo-oxidation was carried out using 8 UVB
fluorescent lamps up to approximately 200 h.
 The adopted cycle consists of 8 h of ultraviolet
irradiation at T =50 ℃ and 4 h without irradiation at T
=35 ℃.
Conclusions
 The photo-oxidation seems to lead to some cross-linking
and chain scission of the synthetic polyester.
 The better performance of benzophenone has been
interpreted in terms of larger absorbance of UV
radiations in the UV wavelength region where the
biodegradable polymer absorbs.