effect of plasticizers on characteristic of bacterial cellulose-alginate-gelatin composite films...
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EFFECT OF PLASTICIZERS ON CHARACTERISTIC OF BACTERIAL CELLULOSE-ALGINATE-GELATIN
COMPOSITE FILMS
PRESENT BY: SUTASINEE SEETABHAWANG
Department of Chemical Engineering, Faculty of Engineering,
Chulalongkorn University, Thailand
ADVISOR : ASSOC.PROF. MUENDUEN PHISALAPHONG, Ph.D.
BACKGROUND
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In order to overcome the problem associated with brittle films after drying, plasticizers
are used to improve the film’s properties.
Biodegradable films for food packaging have attracted and interested because they
could enhance food quality and reduce pollution of traditional plastic films.
The addition of plasticizer can reduce inter-chain interactions, increase film flexibility,
reduce brittleness and prevent the shrinkage of the films.
3
1. To develop composite films from the blends of bacterial cellulose (BC), alginate (A) and
gelatin (G), we called “BC/A/G”
OBJECTIVES
2. To investigate the effects of the blend composition and type of plasticizer on the film
characteristics
3. To determine the physical, chemical and mechanical properties of the films for further
application of packaging materials
INTRODUCTION
1. BACTERIAL CELLULOSE (BC)
BC is a linear polysaccharide of glucose.
(Brown, 1996)4
It can be biosynthesized by Acetobacter xylinum.
PROPERTIES OF BC
INTRODUCTION
Strength
High purity (~99.9% cellulose)
High water holding capacity
Superior water resistance
High mechanical strength
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(Chiaoprakobkij et al., 2011; Brown, 1992; White et al., 1989)
Weakness
Poor ability of rehydration after drying due to its high crystallinity
INTRODUCTION
6
A is a linear polysaccharide copolymer of (1-4)-linked β-D-mannuronic acid (M) and
α-L-guluronic acid (G) monomers.
2. SODIUM ALGINATE (A)
(Pinto Cruz et al., 2004, modified)
It can be isolated from algae and seaweed.
PROPERTIES OF A
INTRODUCTION
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Properties Well-characterized hydrogel forming Water resistance and high mechanical properties
when crosslinked by divalent cations such as CaCl2
Thickener and Stabilizer agent
Non-toxicity
INTRODUCTION
3. GELATIN (G)
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G is a water soluble protein.
(Peña et al., 2010)
Solubility at temp. > 45˚C
It is a thermo-reversible structure.
Setting at temp. < 30 ˚C
PROPERTIES OF G
INTRODUCTION
(Schrieber and Gareis, 2007)9
Strength High gel formation High transparent
Non-toxic
High film-forming capacity
Weakness Poor mechanical properties Poor water resistance
EXPERIMENTAL STUDY
1. Preparation of BC slurry
Unpurified BC
Soaked in 1 %w/v
sodium hydroxide for
24 h
Washed with DI
water until pH = 7 11
BC slurry
Crushed and
homogenized
purified BC
EXPERIMENTAL STUDY
4. Preparation of BC/A/G Films
G
solution
BC
slurry
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A
solution
At 50±5˚C
Vary1: 60/10/30
Vary2: 60/20/20
Vary3: 60/30/10Added plasticizer (Gly, S, and GS) at a ratio
of 0-3 g per 10 g gelatin solution
Homogenous mixture
EXPERIMENTAL STUDY
4. Preparation of BC/A/G Films (Cont.)
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Incubated at room
temperature to form
films
Crosslinked with 1%w/v CaCl2 solution for 1 h
Air-dried at room temperature
RESULTS AND DISCUSSION
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1. Fourier Transforms Infrared Spectroscopy
(FTIR)
A)60/10/30
B)60/20/20
C)60/30/10
D)60/20/20Gly
E)60/20/20S
F)60/20/20GS
3404
2934
1650
142410261536
3400
29251613
1424
1059
14232924
3400 10351614
3401
2928
1650
1431
10351535
3400
2927
1635
1424
1035
3393
2933
1649
143110341541
1241
1316
1316
1243
1250
1243
-NH
(1535-1541 cm-1
)
O-H-O
(1613-1650 cm-1
)
RESULTS AND DISCUSSION
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2. Water Absorption Capacity (WAC)
Condition: the BC/A/G films at ratio of 60/20/20 at room temp.
Wh = Wt. of hydrated films
Wd = Wt. of dried films
B)
C)
A)
CONCLUSIONS
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The composite film with BC/A/G at a ratio of 60/20/20 has superior mechanical properties for
both dry and wet states.
Glycerol is a suitable plasticizer for BC/A/G films because it improves the weakness of the
films.
The optimal ratio of glycerol to gelatin solution is 2:10 (w/w).
ACKNOWLEDGMENTS
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Chemical Engineering Research Unit for Value Adding of Bioresources
Integrated Innovation Academic Center: IIAC Chulalongkorn University Centenary
Academic Development (Project Code: CU56-AM01) (Project Code: AM667A)