Study on Effects of Nanosilica Sand Addition on Physical and Mechanical Properties of Polypropylene (PP)

Problem that arises for attention is polymer degradation issue. Polymer
degradation is a change in the properties - tensile strength, colour, shape - of a
polymer or polymer based product under the influence of one or more environmental
factors. These changes are usually undesirable, such as changes during use, cracking
and depolymerisation of products or, more rarely, desirable, as in biodegradation or
deliberately lowering the molecular weight of a polymer for recycling. It was found
that the addition of nanoparticles in polypropylene will increase the performance of
mechanical properties of the composites. The improvement mechanical and physical
properties of PP will improve all plastic products in industry such as bottle, dustbin,
pipe, jug and chair. Objective of this project is to study on effects of nanosilica sand
addition on physical and mechanical properties of polypropylene (PP). One of the
physical properties that need to be studied is density and the mechanical properties
are tensile strength, Young's modulus and flexural strength. To examinate the
applicability of the study, the silica sand nanoparticles with average particle size of
less than lOOnm was produced by several stages of ball mill and heating
combinations. PP matrix composites with 5, 10, 15 and 20 wt% of silica sand
nanoparticles were developed. The silica sand will be grounded to nanoparticles by
using ball mill with zirconium ball as grinding media. The mixing of nanosilica sand
with PP was carried using internal mixer. After mixing the granular shape of the
mixed particles were produced using granular machine. The resultant particles were
moulded into dog-bone-shaped tensile bars (ASTM D638-97) with an injection
molding machine. Tensile and densities properties of the composites were measured.
Based on the result obtained, there was an increasing trend in Young modulus. The
tensile strength decreased. An increasing trend of density also was obtained with the
increasing content of silica sand nanoparticles in PP. However an improvement in
flexural strength was observed. From experimental values, PP matrix with 20%
addition of nanosilica could be proposed as the optimum mixture ratio. In this
project, although pure PP recorded the highest tensile strength value, common
experimental trend in polymer nanocomposites can be observed from 5% to 20%
particle addition. The effects of silica sand nanoparticles in PP increased its density
and flexural strength but slightly decreased its tensile strength.