Chemistry Reference
In-Depth Information
an unresolved inflammatory response or an extreme immunogenicity or cytotoxicity.
Some attempts via in situ mineralization technique have been done using polymeric
additives such as poly (vinyl alcohol) poly (lactic acid) (PLA), poly (acrylic acid)
(PAAc), collagen, and due to their calcium binding properties. Biopolymers are an im-
portant source of materials for biomedical applications. One of the biopolymers with
biomedical applications is starch. This natural polymer is biodegradable, biocompati-
ble, water soluble, and inexpensive in comparison with other biodegradable polymers.
Synthesis and Characterization of Silver/Clay/Starch Bionanocomposites by
Green Method
Bionanocomposites (BNCs), a novel invention of nanocomposite materials, indicate
a promising field in the frontiers of nanotechnology, materials, and life sciences. The
BNCs are composed of a natural polymer matrix and organic/inorganic filler with at
least one dimension on the nanometer scale. In addition to these characteristics, BNCs
show the extraordinary advantages of biocompatibility and biodegradability in various
medical, drug release packaging, and agricultural applications.
Among natural polymers, starch is one of the most promising biocompatible and
biodegradable materials because it is a renewable resource that is universally avail-
able and of low cost. A number of researchers have presented work in the fi eld of
starch-based BNCs, which can be obtained by fi lling a TPS matrix with nanofi llers
such as layer silicates; MMT and kaolinite are the usual layer silicates used in starch-
based BNCs. The MMT as lamellar clay has intercalation, swelling, and ion exchange
properties. Its interlayer space has been used for the synthesis of material and biomate-
rial nanoparticles, as support for anchoring transition-metal complex catalysts and as
adsorbents for cationic ions. Silver nanoparticles (AgNPs) possess many interesting
and unique properties. It is found in various applications, such as catalysis, electron-
ics, non-linear optics, antimicrobial, and biomaterial applications. Several methods
have been reported for the synthesis of AgNPs, for example, photochemical reduc-
tion, microwave, chemical reduction, and γ-irradiation. The concept of green AgNPs
preparation was fi rst developed by Raveendran, who used β-D-glucose as the reduc-
ing agent and starch as a capping agent to prepare starch AgNPs. A green method for
nanoparticles preparation should be evaluated from three aspects: the solvent, the re-
ducing agent, and the stabilizing agent. In this chapter, we present a simple and green
method for the synthesis of Ag/MMT/Stc BNCs. In here MMT, Starch, β-D-glucose
and AgNO
3
were used as a solid support, stabilizer, green reducing agent, and silver
precursor, respectively. The TEM images show that AgNPs prepared in the edge and
extra surface of MMT layers have large size (39 ± 14.09 nm) and AgNPs intercalated
between MMT layers have small size (9 ± 3.39 nm). The Ag/MMT/Stc BNCs are very
stable in aqueous solution over a long period of time (i.e., three months) without any
sign of precipitation and have potential for various medical applications.
Starch-based Nanocomposites Reinforced with Flax Cellulose Nanocrystals
The development of commodities derived from petrochemical polymers has brought
many benefits to mankind. However, it is becoming more evident that the ecosystem is
considerably disturbed and damaged as a result of the non-degradable plastic materials
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