PREPARATION AND CHARACTERIZATION OF POLYMERIC COMPOSITE MATERIAL

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.