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Methacrylate based nanocomposites with oxidized carbon nanotubes as sound and vibration dumping material

Polymer nanocomposites are often produced to enhance mechanical, thermal, electrical properties of polymer matric. Carbon nanotubes well known for their high stiffness, strength, thermal and electrical conductivity make an ideal candidate for filler in polymer matric. To achieve good dispersion of carbon nanotubes in polymer matric different methods are employed such as solution mixing, melt mixing and in situ polymerization. Furthermore, carbon nanotube surface is often modified in order to improve molecular interaction with polymer matric. Vibrations and noise are undesirable side effects of working mechanical and electrical devices. Their reduction can be achieved by insolation with high damping capacity material. There are two main damping mechanisms: one arising from viscoelasticity of materials and the other from phase boundaries energy dissipation. Polymers are commonly used for vibration damping because of their viscoelastic character. Moreover, composite materials are produced to increase phase boundaries. In these work methyl methacrylate and hexyl methacrylate or dodecyl methacrylate copolymer nanocomposites were prepared by free radical in situ polymerization. Oxidized carbon nanotubes were added as 1 % and 5 % wt. filler in monomer solutions. Prepared nanocomposites were examined by dynamic-mechanical analysis (DMA) in order to determine glass transition temperature and primary viscoelastic functions (storage modulus, loss modulus, tan delta). Modified dynamic-mechanical analysis according to ISO 6721 (Oberst's method) was used to determine loss factor of material, which is a direct measure of capability of material to absorb energy of vibration and sound. Influence of content of carbon nanotubes on molar masses of methacrylate copolymer was examined. Scanning electron microscopy was utilized to observe morphology of nanocomposites.

carbon nanotubes; damping; methacrylate copolymer

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