Study on thermoplastic cassava starch modifications via chemical, photo and irradiation induced crosslinking
The characterization of modified thermoplastic starch (TPS) was investigated by means of mechanical properties, thermal properties, scanning electron microscope (SEM), Fourier transform infrared spectroscopy, high performance liquid chromatography and biodegradability test. Before performing the...
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| Format: | Thesis |
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| Language: | English |
| Subjects: | |
| Online Access: | http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77993/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77993/2/Full%20text.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77993/4/Amirah%20Hulwani.pdf |
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| Summary: | The characterization of modified thermoplastic starch (TPS) was investigated by means of
mechanical properties, thermal properties, scanning electron microscope (SEM), Fourier
transform infrared spectroscopy, high performance liquid chromatography and
biodegradability test. Before performing the modification, the TPS was prepared by
plasticized 65 % of native cassava starch with 35 % of glycerol. The TPS was prepared by
using heated two roll mill at the 150 oC for 10 minutes. Different type of modification,
which photo radiation, electron beam radiation crosslinking, and carboxylic acid
modification was prepared on TPS sheets. In photo crosslinking, TPS were irradiated under
lamps at different irradiation time, from 30 minutes to 480 minutes. Meanwhile, dosage
ranging from 25 kGy to 100 kGy were introduced in electron beam radiation crosslinking
process. Crosslinking of TPS using photo radiation and electron beam radiation showed
improved thermal properties and mechanical properties, which 2.70 MPa and 3.18 MPa
respectively. The gel mass (NGM) value increases up to 22.98 mg/cm2 and 19.28 mg/cm2,
respected to the photo irradiation time and electron dose range proved the formation of
crosslinking in the TPS. However, excessive irradiation caused further degradation of the
TPS, thus reduce the crosslinking formation. Citric acid and ascorbic acid were introduced
into the chemical modification process of TPS. Addition of carboxylic acid were varied
from 1% - 4%, and 10% - 50%. Based on SEM analysis, the addition of carboxylic acid
gives a smoother fracture surface. Further increment in carboxylic acid content led to the
crosslinking formation. The NGM value was increase until 49.00 mg/cm2 and 57.43
mg/cm2, respected to increases of citric acid and ascorbic acid content. As a resulted, the
tensile value at 40% was increased up to 6.25 MPa compared to unmodified TPS. Moisture
absorption analysis also showed improved moisture resistivity as compared to unmodified
TPS. Biodegradability test performed resulted acid modification TPS give low degradation
rate compared to unmodified TPS. These was due to their improved moisture resistivity,
resulted reduce in the water permeability into the TPS structure |
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