Abstract:
Composite materials are superior to other known structural materials in specific strength
and stiffness, high temperature strength, fatigue strength and other properties. The
present study was carried out to prepare such types of polymer composites which
possess the better properties than the pure polymer. In this study we prepared seven
different types of composites of PMMA with clay, Na2SO4, CaCO3, activated carbon,
SiO2, ceramics and glass, PMMA was used as Matrix. The films were prepared by
solvent cast method, using benzene as solvent. The structure and properties of these
composites were investigated by SEM, EDX, DSC, UTM, TG/DTA and FTIR
techniques. SEM of pure PMMA showed uniform surface while the morphology
changed by the addition of various fillers .Clay, glass and Na2SO4 were uniform and
well dispersed in PMMA matrix while CaCO3 show somewhat spherical structure, SiO2
and ceramics seemed to be embedded in between cavities. The size of the particles
varied with the system. EDX studies on all these composites showed that the particles
were incorporated in the PMMA matrix and have sufficient amount in the matrix. FTIR
studies revealed that there was interaction between the polymer molecule and the
various fillers added to them .The peak at 1729 cm -1 in PMMA was assigned to be due
to C=O group. This is strong electron donor group so the cations tend to make
complexes with this group. It was shown that the cations of Na+, Ca++ and Si++ interact
with this and shift toward lower wave number. In the case of clay, the silicates present in
the clay tend to interact and shift it again toward lower wave number. The thermal
properties of all these composites were studied. These TGA showed that the added
materials in to polymer matrix increased the thermal stability .The order of increasing
thermal stability of various composites was:
PMMA < PMMA-activated carbon < PMMA-SiO2 < PMMA-Na2SO4 < PMMA –
CaCO3 < PMMA- clay < PMMA-ceramics < PMMA-glass
The glass composite showed maximum thermal stability among all the studied
composites. The mechanical studies of these composites were investigated by universal
testing machine .It was shown that the tensile strength of the tested composites were
much better than the pure PMMA. The order of increasing tensile strength of various
composites was:
PMMA < PMMA-Na2SO4 < PMMA-glass < PMMA- clay < PMMA-ceramics <
PMMA -CaCO3 < PMMA-SiO2 <PMMA-activated carbon
The activated carbon composite showed maximum tensile strength among all the studied
composites. The elongation at break was another parameter showing strength of material
and the values of elongation at break for the composites was found to be higher than the
pure polymer. The order of increasing elongation at break of various composites was:
PMMA < PMMA-Na2SO4 < PMMA-activated carbon < PMMA- clay < PMMA-
ceramics < PMMA-glass < PMMA -CaCO3 ≤ PMMA-SiO2
Finally, the present study has shown that various composites of PMMA have been
successfully prepared showing incorporation of filler. The interaction of cations of the
compositing materials with the polymer has also been shown. The composite materials
showed improved thermal and mechanical stability.