Polymeric Composite Resins in Compression Moulding - Introduction to Polymeric Composites with Rice Hulls - page 139

12

Polymeric Composite Resins in
Compression Moulding

In the plastics moulding industry, in compression moulding, traditionally the polymer
resins used have been virgin or recycled thermosets (harden on heating and cannot be
reused) or thermoplastics (soften on heating and can be reused). Polymers in powder
form, pellets or pre-pregs can be compression moulded easily. This process is generally
used for moulding large solid parts, mostly for the industrial and automobile sectors.
As discussed is Chapter 9 , now PCRH are available and these can be moulded to
produce large parts using conventional equipment and machinery. These new resins
are available in their natural colour or in colour, and moulders also have the option
of colouring in situ . Some of the advantages of using these composite resins include
better properties and reduced material costs. Also, polymeric thermosetting composites
with rice ash are available for compression moulding.

12.1 Uses of Rice Hull Ash

I feel compelled to present some information on this valuable emerging commodity
for the benefit of the reader. The very high content of silica in the ash mass, the
availability in abundance in many countries and its cost-effectiveness has led to its
use in many industrial applications and will no doubt create many new and diverse
possibilities for the future.

12.1.1 Steel Industry

Rice hull ash is used in the steel industry for producing high-quality flat steel, a plate
product or a hot rolled strip product, which are usually employed in automotive
body panels. The ash also finds application as an excellent insulator, having low
thermal conductivity, a high melting point, low bulk-density and high porosity. This
fine powder is used to insulate a container for pouring molten metal into a mould,
enabling the prevention of rapid cooling of the steel pour and ensuring uniform
solidification in a casting process.