Radiation Processing of Natural and Synthetic Polymers for ... · Radiation Processing of Natural...
Transcript of Radiation Processing of Natural and Synthetic Polymers for ... · Radiation Processing of Natural...
Radiation Processing of Natural
and Synthetic Polymers for
Potential Applications El-Sayed A. Hegazy
Former Chairman, National Center for
Radiation Research
and Technology
Atomic Energy Authority
Cairo, Egypt
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OBJECTIVE:
To study the effect of ionizing radiations on
the crosslinking and degradation of some
natural polymers such as CMC-Na, chitosan
and alginate. Super absorbant materials
and nano gels were prepared by radiation
copolymerization of natural and synthetic
polymers for possible use in industrial,
agricultural and biomedical applications.
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CMC Concentration (%)
Gel
Co
nte
nt
(%)
0
5
10
15
20
25
10 20 30 40 50 60 70 80 90
Effect of different CMC concentrations in water on its gel content at 20 kGy using
EB irradiation in air atmosphere.
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Gel content (%) of cross linked CMC-Na as a function
of irradiation dose at 35 oC.
Irradiation Dose (kGy)
0 5 10 15 20 25
Gel
Co
nte
nt
(%)
0
5
10
15
20
25
30
35
30%CMC-Na
40%CMC-Na
50%CMC-Na
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Effect of applied irradiation dose on the swelling ratio of
crosslinked CMC-Na in distilled water (50 wt%).
Time (min.)
0 10 20 30 40
Sw
elli
ng
Rat
io (
g/g)
0
20
40
60
80
100
120
140
160
18020kGy.
30kGy.
40kGy.
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Effect of irradiation dose on the degradation of chitosan in the presence and
absence of additives
Irradiation Dose ( kGy )
0 20 40 60 80 100 120 140 160 180 200
Ch
ito
san
Mo
lecu
lar W
eig
ht
x 1
06
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
Blank
With 10% H2O2 ( v / w )
With 20% H2O2 ( v/ w)
With 10% KPS ( w / w )
With 10% APS ( w / w )
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Effect of irradiation on the degradation of Na-alginate
in the presence and absence of additives.
Irradiation Dose ( kGy )
0 20 40 60 80 100 120 140 160 180 200
So
d. A
lgin
ate
Mo
lecu
lar W
eig
ht
x 1
04
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
Blank
With 10% H2O2 ( v / w )
With 20% H2O2 ( v / w )
With 10% KPS ( w / w )
With 10% APS ( w / w )
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Use of Degraded Natural polymers in
agriculture as a growth promoter
Degraded Na-alginate and chitosan could be used as a growth promoter for plants in agriculture purposes. The growth and other responses of zea maze plant treated with irradiated Na-alginate or chitosan of different MWts were studied.
The test field results showed that the treatment of the zea plant with irradiated Na-alginate at 120, 160, and 200 kGy in the presence of APS resulted in increasing the growth in plant. Meanwhile, the use of chitosan under the same conditions enhances the plant growth and productivity as well.
The increase in plant performance by using degraded alginate or chitosan suggested its acceptable use in agriculture field as growth promoter.
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The growth and other responses of zea maze plant treated with
irradiated Na-alginate of different MWts in APS
20
kGy 200 kGy 160 kGy 120 kGy 80
kGy
0
Contro
l
SA Treated by 10% APS
40
kGy
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Radiation Cross-linking of Natural Products/
PAAm For the Use as Super Adsorbent
Hydrogels
Super Adsorbent Hydrogels are used in
various fields including bandages and wound
dressing, controlled drug delivery, humidity-
controlled products, soil conditioners,
controlled release of fertilizers, aqueous
waste management and gelling agents,
medical health care products..etc.
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Gel content of crosslinked CMC-Na:PAAm as a function of
irradiation dose extracted at 50oC after 24hr.
Irradiation Dose (kGy)
0 5 10 15 20 25
Gel
Con
ten
t (%
)
0
10
20
30
40
50
60
70
80
50:50
60:40
70:30
80:20
CMC-Na:PAAm
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Effect of polymer composition on the swelling ratio of crosslinked
CMC-Na:PAAm hydrogel, Polym. conc. 30 wt%. Irrad. dose 10kGy
Time (min)
0 5 10 15 20 25 60
Sw
elli
ng
Ra
te (
g/g
)
0
50
100
150
200
250
70/30
60/40
50/50
80/20
0/100
CMC-Na/PAAm
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Time(min.)
0 5 10 15 20 25
Sw
ell
ing R
ati
o (
g/g
)
0
50
100
150
200
with blowing agent
without blowing agent
Swelling ratio of CMC-Na:PAAm hydrogels (50:50) in distilled
water.Polym.conc. 30 wt% Irrad. dose 10kGy in Am Carbonate.
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Bean plant cultivated in soil after 9 weeks:
(A) Untreated (control), (B) Treated with PAAm and (C) treated
with PAAm/Na-alginate.
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Swelling ratio of CMC-Na/PAAm superabsorbent hydrogel and
commercial diaper in simulated urine solution.
Time (min.)
0 5 10 15 20 25 30
Sw
ell
ing
Ra
tio
(g
/g)
0
10
20
30
40
5050:50 (CMC-Na:PAAm)
commercial diapers
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Application of PNIPAAm grafted with
some natural polymers
Effect of natural polymer on the release of ketoprofen from its
corresponding copolymer with PNIPAAm at pH 1 and 7.
Radiation synthesis of nano-
sized hydrogel particles based
on the interpolymer
complexation between
polyvinylpyrrolidone and
polyacrylic acid by gamma
radiation
DLS Results of
irradiated (40 kGy)
PVP/PAAC
(a) pH 4
(b) pH 7
Volume-weighted Gaussian distribution analysis for irradiated (40 kGy)
PVP/PAAC at pH 4 and 7. Feed composition: PVP/PAAc (35/65 mol/mol
%); total conc. 0.5%; PVP 1300000.
Dav=280 nm
PDI=0.176
Dav=200 nm
PDI=0.165
Synthesis of PVP/PAAc nanogels by
gamma irradiation in air atmosphere:
Figure (3) AFM image for PVP and PAAc
polymers
Multimodal
distribution
for the
particles
obtained
from PVP/
PAAc
polymers
DLS results for system (B): PVP/AAc in deionized water at pH 4.
PVP/AAc: 35/65 mol/mol %; Total conc.: 1.5%; PVP Mw = 1300000;
20 kGy.
DLS results for
PVP/AAc aqueous
solution at pH 4
Dav=83 nm
PDI=0.041
DLS results for
N-VP/PAAc aqueous solution
at pH 4
DLS results for system (C): N-VP/PAAc in deionized water at pH 4.
N-VP/PAAc: 35/65 mol/mol %; Total conc.: 1.5%; PAAc Mw = 497000; 20
kGy.
Dav=57 nm
PDI=0.086
AFM image (topography and three dimensional) of PVP/PAAc nanogel
particles investigated in deionized water.
Possible Bio-medical
Applications of PVP/PAAc
Nanogels
Treatment of dry eye syndrome
Topical application of PVP/PAAc nanogel
dispersions in an experimental dry eye
model in albino rabbits
Dry eye syndrome is a
chronic eye disease which
is associated with
symptoms of discomfort,
visual disturbance and
abnormal tear film from
either tear deficiency or
excessive tear evaporation
Topical application of PVP/PAAc
nanogel dispersions in an experimental
dry eye model in albino rabbits
An experimental dry eye model in albino rabbits was
carried out using atropine sulfate 1% eye drops
The model produces some typical dry eye symptoms
such as a significant reduction in the tear volume and
tear break-up time (TBUT), corneal staining, and
histopathological signs of dryness and inflammation.
The prepared PVP/PAAc nanogels (1.5 w/v%, pH 7.4)
were used for the treatment of the dry eye model, and
the obtained results were compared with that of
commercial carbomer gel “Vidisic, 0.2%”
Untreated dry eye model
Ulcer
Treated dry eye model
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Conclusion
It can be concluded that radiation is a very
effective tool for controlling the degradation and
cross-linking of natural occurring polymers and
the synthesis of relative economic,
environmentally friendly super-absorbent
hydrogels which may potentially be used in
personal care products industry, in agriculture
as a growth promoter, and in medical uses as
drug delivery under control release to specific
sites.
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Many Thanks
for your kind attention