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Abstract:
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The present work focuses on the modification of the commonly used
thermoplastics, polypropylene and polystyrene using nanosilica preparcd
from a cheap source of sodium silicate. Melt compounding technique has
been used for nanocomposite preparation as it is simple and suited to
injection moulding. Nanosilica in a polymer matrix provide significant
enhancement in strength, stiffness and impact strength. Incorporation of silica
particles in a polymer also improves its thennal stability. To achieve better
dispersion of fillers in polymer matrices the mixing was done at different
shear rates. The enhancement in material properties indicates that at higher
shear rates there is greater interaction between particles and the matrix and it depends on filler concentration and type of polymer used. N anosilica is a
useful filler in thennoplastic polymers and has been applied in automotive
applications, electronic appliances and consumer goods.This thesis is divided into six chapters. General introduction to the
topic is described in chapter 1. Salient features of polymer nanocomposites,
their synthesis, properties and applications are presented. A review of
relevant literature and the scope and objectives are also mentioned in this
chapter.The materials used and the vanous experimental method and
techniques employed in the study are described in chapter 2. Preparation of
nanocomposites by melt blending using Thenno Haake Rheocord,
preparation of samples, evaluation of mechanical and thennal properties
using UTM, Impact testing and characterization using DMA, TGA and DSC
and morphology by SEM are described.The preparation of nanosilica from a laboratory scale to a pilot plant
scale is described in chapter 3. Generation of surface modified silica,
evaluation of kinetic parameters of the synthesis reaction, scale up of the
reactor and modeling of the reactor are also dealt with in this chapter.The modification of the commodity thennoplastic, Polypropylene using
nanosilica is described in chapter 4. Preparation of PP/silica nanocomposites,
evaluation of mechanical properties, thermal and crystallization characteristics,
water absorption and ageing resistance studies are also presented.The modification of Polystyrene using synthesized nanosilica IS
described in chapter 5. The method of preparation of PS/silica nanocomposites, evaluation of mechanical properties (static and dynamic),
thermal properties melt flow characteristics using Haake Rheocord, water
absorption and ageing resistance of these nanocomposites are studied. |