Preparation and Characterisation of Polystyrene Grafted Sago Starch
Styrene grafting onto sago starch was carried out by using eerie ammonium nitrate (CAN) as a redox initiator. The parameters affecting the grafting reaction were investigated and the optimum conditions obtained are as follows: temperature, 50°C; nitric acid concentration, 0.01 M; amount of styre...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English English |
| Published: |
1999
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/9499/1/FSAS_1999_36_A.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Styrene grafting onto sago starch was carried out by using eerie
ammonium nitrate (CAN) as a redox initiator. The parameters affecting the
grafting reaction were investigated and the optimum conditions obtained are
as follows: temperature, 50°C; nitric acid concentration, 0.01 M; amount of
styrene, 0.35 mol; amount of CAN, 16.8 x 10-4 mol and reaction period, 2h.
Percentages of grafting and grafting efficiency under the optimum condition
were 53.92% and 73.21%, respectively. Reactions in the presence of
nitrogen gas resulted in higher percentages of grafting and grafting
efficiency.
FTIR spectra analysis of the grafted chain and polystyrene was
identical indicating that styrene was successfully grafted onto sago starch.
TGA thermograms, DSC curves and SEM photographs of sago starch-g poly(styrene) and the original polymers (sago starch and polystyrene) were
different which suggested that styrene was grafted onto sago starch. The
bio-degradability study using a-amylase showed that the rate of degradation
of gelatinised sago starch was higher than that of sago starch-gpoly(
styrene). The highest rate of degradation of sago starch-gpoly(styrene) was obtained at 50 ppm of a-amylase concentration. Viscosity
measurements showed that the intrinsic viscosity and the average molecular
weight (Mv) increased with the increase in the percentage of grafted
polystyrene. The Mv of the various percentages of grafted polystyrene were
in the order of 104. The results obtained from the swelling of sago starch-gpoly(styrene) in polar and non polar solvents showed that the percentage of
swelling at equilibrium and the swelling rate coefficient decreased in the
following order: DMSO > water > acetone > cyclohexanone = CHCh >
toluene = CCl4. Diffusions of the solvents onto the polymers were found to
be of a Fickian only for DMSO. |
|---|