Nondestructive testing of defects in adhesive joints

1. Introduction
Polymer nanocomposites have been intensely researched in the last decade since the
addition of a small quantity of reinforcement fillers such as clays in the polymer matrix have led
to improvements of mechanical, thermal, and barrier properties. 1-2 . The nano-sized fillers have
dramatically increased the surface area compared with conventional-sized materials. The
increased surface area of nano reinforced materials is responsible for the improvement in
properties of nanocomposites compared to pure polymers or filled with conventional fillers. The
nanocomposites are new class of composites that are particle filled materials in which at least one
dimension of dispersed particles is in the nanometer range.
Polymer matrix must have good process properties so that the dispersed particles can
result in a large improvement in composite properties. 3-4
Normally mixing is done on two roll mill. But proper mixing (dispersion) of fillers is
very important to achieve maximum level of properties. Hence in addition to two roll mill we
mixed nanoparticles into SBR by using Brabender Plastograph and compared both the techniques
for performance.
2. Experimental
2.1 Materials
Styrene butadiene rubber (SBR)
Rubber additives Viz. stearic acid, zinc oxide (ZnO), zinc diethyl dithiocarbamate (ZDC),
mercapto benzothiozyl disulphide (MBTS), vulconex, and sulphur,
Calcium chloride (AR Grade), potassium carbonate, and poly (ethylene glycol) (PEG;
molecular weight of 6000) for synthesis of nano CaCO3.
2.2 Preparation of nanoparticles
The nano-sized calcium carbonate particles were synthesized in the laboratory by using-
• Matrix mediated growth and controlled i.e. in situ deposition technique. 5-10
2.3 Preparation of Rubber nanocomposites
Two different techniques were used for preparation of styrene butadiene rubber (SBR)
nanocomposites 1) Two roll mill
2) Brabender Plastograph
2.4 Characterization
The following characterization techniques were used-
1. Particle size determination - X-ray powder diffraction technique.
2. Mechanical (Tensile properties) - Universal Testing Machine
3. Hardness- Hardness tester Shore scale-A