Abstract:
The advantages of nanocomposites containing
single silicate layers uniformly dispersed in a polymer matrix
were first demonstrated by researchers at Toyota in Japan, who
developed nylon-6 nanocomposites and published in 1993.
Polymer-nanoclay nanocomposites have attracted the attention of
many researchers thereafter due to their outstanding mechanical
and barrier properties. This concept is first applied to synthesis
of plastics/nanoclay nanocomposites and then expanded to
preparation of rubber/nanoclay nanocomposites, since few years
later. The various types of synthetic rubbers, such as silicon
rubber, nitrile rubber and epoxy rubber, were used to prepare
nanocomposites using different techniques, namely, melt
intercalation, in situ intercalative polymerization, exfoliationadsorption
and template synthesis, etc. Natural rubber (NR) was
also used to prepare nanocomposites using the same techniques
but with some modifications in the last decade. Now a day’s
nanocomposites are widely developed in NR latex industry to
achieve required properties with minimum use of clay content.
NR/nanoclay nanocomposites exhibit markedly improved
properties when compared to pure NR or their traditional
composites. Most notable properties are increased tensile
properties, gas barrier properties and heat distortion
temperature, resistance to small molecule permeation, increase in
atomic oxygen resistance and retention of impact strength.
Tensile strength and modulus were recorded in current research
as enhanced by more than two times or even ten times. It was
noticed that obtaining a fully exfoliated structure is not at the
desired level. Nanoclay nanocomposites are considered as fully
exfoliated when inter gallery distance is greater than 10 nm but it
was not achieved in many research work. Establishment of
exfoliated structures in nanocomposites prepared in industrial
scale is the major challenge that NR industry faces at present.
NR/nanoclay nanocomposites produced with existing techniques
develop high property fluctuations. Therefore, it is necessary to
develop a technique to minimize property fluctuations and to
obtain a reliable NR based product. It is predicted by this review
that co-coagulation technique is the most promising and potential
technique to fulfill the requirements of developing a NR/nanoclay
nanocomposite. Use of modified nanoclays like Organoclays will
aid to obtain a reliable NR based product.
