engleski

Synthesis and characterization of polystyrene composites with oxidized and ethyl-benzene functionalized multiwall carbon nanotubes

Polystyrene nanocomposite materials prepared with differently functionalized multiwalled carbon nanotubes (CNT) as nanofillers were investigated. Two types of functionalized multiwall carbon nanotubes were used: oxidized (CNT-COOH) and their ester analogue with ethylbenzene groups (CNT-COOEtBz) introduced by further functionalization of the fore. The functionalized nanotubes were examined by thermogravimetric analysis and contact angle method that both revealed differences between them. Also, their dispersion was investigated in polar methanol and non-polar toluene with the assistance of UV-Vis spectrophotometer. Good dispersion of CNT-COOH in methanol and of CNT-COOEtBz in toluene is in accordance with polarity introduced on the surfaces of carbon nanotubes. Mixtures of styrene monomer and 1 wt. % of CNT-COOH or CNT-COOEtBz in toluene were reacted in a radical in-situ polymerization reaction in order to prepare their nanocomposites. Prior to the reaction nanotubes were dispersed by sonication of the reaction mixture. The synthesized composites were characterized by the SEC, TGA, DSC, DMA, SEM and contact angle method. The DSC measurements show a significant Tg shift towards lower temperature since Tg of studied PS is around 60 oC and Tg of PS composites with CNT-COOH at 35 oC and CNT-COOEtBz at 33 oC. The storage modulus increase in the PS/CNT-COOEtBz composite can be assigned to a larger similarity of matrix and filler structure. This is corroborated with the SEM micrographs where much lesser extent of agglomeration can be seen.

contact angle ; dispersity ; loss factor ; storage modul ; thermal stability

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