The document discusses biodegradable starch-clay nanocomposite films for food packaging. Starch is obtained from plants and is biodegradable, while clay is added to improve properties. The films are prepared by dispersing clay into starch with glycerol and heating. Characterization with FTIR, XRD and SEM show the clay is well dispersed in the starch matrix. The films are insoluble in water but degrade when exposed to microorganisms, suggesting potential use as biodegradable food packaging.

2. INTRODUCTION

3. WHAT IS PLASTIC ?

4. 1.Plastics are synthetic polymer which is used for packaging
materials for food and non-food products due to their desirable
properties and low cost.
2.Most synthetic polymers oare harmful to nature
3.Their synthesis produces hazardous waste and these materials are
not easily degradable, causing tremendous problems to our
environment.
4.The merits of plastic packaging have been overshadowed by
its non-degradable nature, thereby leading t waste disposal
problems

6. STARCH/CLAY
NANOCOMPOSITE
 Starch are completely and quickly biodegradable and easy to process because of its
thermoplastic nature
 obtained from many plants and its rather excessive production with regard to current
needs and its low cost .
 It consist of two polysaccharides, the linear amylose and the highly branched
amylopectin
 The pure native starch films are brittle so the addition of plasticizers such as glycerol,
urea and formamide used to improve the barrier and mechanical properties of starch-
based biodegradable packaging films
 This aid in the thermoplastic process and also increase flexibility of the final product by
forming hydrogen bonds with starch.

7. Materials and methods
All reagents (expect water) were purchased from the
Himedia and used without modification.
 Deionized water was purified by milli–Q water system
(Millipore Corporation) and filtered through various
filter to remove any impurities.
The materials used for the preparation of
nanocomposite films are potato starch and purified clay
mineral with cation-exchange capacity (43 meq/100g).

8. Preparation of Starch- Clay
nanocomposites film
starch was dispersed in distilled water with 20 wt% of
glycerol. Then the suspension was heated to 700 C for 30
min under continuous stirring to gelatinize the starch
granules.
clay mineral was dispersed in distilled water by sonication
during 10 min at room temperature. The clay dispersion
was added to the aqueous dispersion of starch and the
mixture was continued to sonicate for 30 min at room
temperature.

9. solutions were then poured onto acetone to
precipitate the resultant starch/clay nanocomposites,
followed by the solvent evaporation to dryness at
65ºC. Then, the films were obtained by casting pouring
the hot suspension into rectangular moulds and
evaporating it in an oven at 450 C .
Portions of the conditioned films were dried at 1100C for 12
h. After weighting, they were conditioned at 250 C in a
desiccators at 43% r.h., then removed at specific time
intervals and weighted. The differences between the initial
and final masses correspond to the water loss, thus
determining the amount of moisture retained by the
films.

10. Characterization methods
 FT-IR spectrum was recorded on Perkin Elmer FTIR 1650
spectrophotometer at ambient temperature using KBr pellet method.
The pellet was scanned at 16 scans at wave number range of 400-
4000cm‫.¹־‬
 XRDanalyses of the composites were performed in a Bruker Discover
8 diffractometer operating at 40 kV and 40 mA. The crystallographic
study was performed on the synthesized Starch- Clay nanocomposites
by X-ray diffractometer.
The nature of the nanocomposites was calculated using Bragg’s law
and the crystallinity was determined dividing the crystalline area by
the total (crystalline + amorphous) area. Silicon powder was used as
the internal standard.

11. scanning electron
microscope (SEM)
Investigate the morphology of the starch-clay
nanocomposites. The specimens were frozen
under liquid nitrogen and fractured and
coated with gold on a ion sputter coater. SEM
micrographs were obtained using 15 kV
secondary electrons at a magnification of 20000
to 150000X to find out the shape and size of the
particles.

12. Results and discussion
Fourier Transform Infra-Red (FT-IR) Spectroscopy
FTIR results of the present study in Fig. 1 shows the spectrum
of Starch- Clay nanocomposites. The peak observed at
3567cm-1 which can assign to be –OH stretching vibration of
water and hydroxyl groups. The peak at 945.45 cm-1 was
attributed to C-O stretching . The bands in the region of 2933
cm-1 are due to C-H stretching while the bands in the region
around 1465- 1356cm-1 are attributed to CH2 bending in the
plane. The hybrid materials band at Si- O stretching was
observed at 445 cm-1 and its intensity increases in the hybrid
films with large amount of clay .

13. X-Ray Diffraction Analysis (XRD)
 X-ray diffraction (XRD) is an effective method for the investigation of the intercalation
existence of mineral clay.
 The X-ray diffraction pattern taken from Starch- Clay nanocomposites is shown in fig. The
X-ray Diffraction peaks of starch- clay nanocomposites displays at 2Ө=56.66; 64.88; 75.57
corresponding to d001 value of 1.63, 1.43,and 1.25 A0 respectively (Fig.4).
 The mean values for starch- clay nanocomposites was calculated as Bragg’s law [10]. Native
starches generally exhibit two main crystalline types, namely, the A-type for cereal starches
and the B-type for tuber and amylose-rich starches (Bule´on et al., 1998).
 The numbers of diffraction patterns were observed in the X- ray Diffraction spectrum
indicating that the presence of mineral clay layer in the Starch. The characteristic difference
between their XRDs is that B-type has a strong diffraction at 2θ = 5.50 (Tester and Karkalas,
2004). The diffraction studies confirm a high degree of crystallinity and uniformity in the
particles.

14. Scanning Electron
Microscopy analysis (SEM)

15. The surface morphology of Starch- Clay
nanocomposites films under SEM as shown in Fig.
was to investigate clay aggregation in the starch
matrix and can be seen that
Nanocomposites have well defined monodispersed
spherical shapes.
The sizes of the Starch- Clay nanocomposites have a
diameter of 20 – 40 nm.

16. Solubility test

17. The solubility test in water and solvents such as acetone,
ethanol, hydrochloric acid (HCl) and sulphuric acid (H2So4).
The Starch- Clay nanocomposites film was put in distilled
water and left for 15 days, it remains as such which
results the film is insoluble in water.
When the nanocomposites film was kept in solvents ethanol
(50%) and acetone (50%) the film is insoluble and no
change its morphological nature for nearly 15 days but when
placed in hydrochloric acid (50%) and Sulphuric acid (50%
) the film immediately ruptured and dissolved in the acid.

18. Biodegradability Test
 Five microbial species were tested in the
laboratory for their ability of degrading the
nanocomposites films.
The species tested were E.coli, Pseudomonas
sps, Staphylococcus aureus species and two
fungal species - Aspergillus niger and
Fusarium oxysporum.

20. Table 1. Degradation of the nanocomposites films incubated with
different microbial species in shaker cultures under laboratory
conditions
S.No Name of
microorganism
Microbial
degradation
(% weight loss /
month)
1 Escherichia coli 22.42 ± 0.21
2 Pseudomonas sp. 15.89 ± 0.10
3 Staphylococcus aureus 10.54 ± 0.26
4 Fusarium oxysporum 25.76 ± 1.23
5 Aspergillus niger 18.24 ± 1.01

21. conclusion

22. Biodegradable starch-clay nanocomposites films were prepared by
dispersing clay particles into the starch matrix via melt extrusion
processing.
The film properties of the nanocomposites films were greatly
influenced by clay content.
The FT-IR, XRD and SEM results revealed that dispersion of clay in
the starch matrix depended on the compatibility and the polar
interactions among the starch and glycerol to form agglomerations.
The Solubility test revealed that the film is insoluble in water which
allows low humidity and the biodegradability nature of starch-clay
nanocomposites films could be used as environmentally friendly food
packaging materials for extending shelf life and reduce the menace
caused by the non degradable plastics.