Nondestructive testing of defects in adhesive joints

II) Elongation at break (% Elongation)
For all compositions, elongation at break of nanocomposites increased with increasing
filler content up to 3 wt % and 4 wt % filler loading for both Brabender and two roll mill
respectively. Value of elongation at break decreased after attaining the peak value, the trend was
found to be similar in both the techniques. The reason may be agglomeration of nano particles as
well as formation of weaker interfacial region between the filler surface and matrix where in
cracks develops.
% Elongation
700
650
600
550
500
450
400
0 1 2 3 4 5
Filler content (w t%)
Tw o roll mill
Brabender
Figure 3. % elongation of SBR filled with nano CaCO3 processed on two roll mill (TRM)
and Brabender Plastograph
3. Hardness
Hardness of all composition increased up to 4 wt % of filler amount for both mixing
technique than the pure SBR composites as shown in figure. Hardness increased due to the
greater degree of crosslinkage which has been occur during vulcanization of rubber
nanocomposites by uniform transfer of heat in to the rubber matrix. Also the formation of
effective layer is responsible for increase in hardness of rubber nanocomposites.
Hardness
48
47
46
45
44
43
42
41
0 1 2 3 4 5
Filler content (w t%)
Tw o roll mill
Brabender
Figure 4. Hardness of SBR filled with nano CaCO3 processed on two roll mill (TRM) and
Brabender Plastograph