Studies on the use of nano zinc oxide and modified silica in NR, CR ...

Chapter 1
Mechanical process
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These include grinding, milling and mechanical alloying techniques.
Provided that one can produce a coarse powder as a feed stock, these process
utilize the age-old technique of physically pounding coarse powders into
finer and finer ones, which is similar to the grinding flour mills. Today, the
most common processes make use of either planetary or rotating ball mills.
The advantages of these techniques are that they are simple and require low-
cost equipment. However, there can be difficulties such as agglomeration of
the powders, broad particle size distributions and contamination from the
process equipment itself. Often there would be difficulty in getting the very
fine particle sizes with viable yields. It is commonly used for inorganic
materials and not for organic materials.
Using templates to form nanoparticles
Any materials containing regular nano-sized pores or voids can be
used as a template to form nanoparticles. Examples of such templates include
porous alumina, zeolites, diblock co-polymers, dendrimers, proteins and
other molecules. The template does not have to be a 3D object. Artificial
templates can be created on a plane surface or on a gas-liquid interface by
forming self-assembled mono layers.
1.3 Polymer matrices - Elastomers
Different types of polymers are used as matrices in composites.
Elastomers are one of the most interesting materials on account of its range of
applications. These polymers have unique properties of deformation and
elastic recovery after vulcanization with sulphur or other cross linking agent,
which in effect change the polymer from thermoplastic to thermosetting.
Natural rubber (NR) is a commonly used rubber and has been used for the
production of different products.