- Functionalized MWCNTs, an efficient reinforcement for the preparation of eugenol based high performance PBz/BMI/CNT nanocomposites exhibiting outstanding thermo-mechanical properties
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The chemistry of benzoxazine synthesis offers wide molecular design flexibility and thus facilitates preparation of various polybenzoxazine based composites. In this paper, we reported the preparation of polybenzoxazine/BMI blend and subsequent preparation of nanocomposites with amine functionalized multiwalled carbon nanotubes (F-MWCNTs). The curing mechanism and the material properties of the blend and nanocomposites were studied extensively. DSC analysis showed two exothermic maxima, corresponding to benzoxazine and allyl group polymerization. Furthermore, by the incorporation of F-MWCNTs into the PBz/BMI system, the properties of the PBz/BMI/F-MWCNT nanocomposites were improved significantly. The enhancement in the material properties is due to the strong interaction between the F-MWCNTs and PBz, resulting in the formation of interpenetrating polymer networks. The morphology and fracture surface of the nanocomposites were studied by scanning electron microscopy. The thermal, mechanical and dielectric properties of the nanocomposites are found to be outstanding when compared with the neat PBz and PBz/BMI blend.
- Periyasamy, Thirukumaran,Asrafali, Shakila Parveen,Kim, Seong-Cheol
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- Synthesis and characterization of novel bio-based benzoxazines from eugenol
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Polybenzoxazines are phenolic-like materials that possess dimensional and thermal stability, and they release no by-products during their polymerization. In this study, a new class of benzoxazine-containing monomers has been prepared from renewable resource (eugenol, a natural phenol obtained from clove oil), paraformaldehyde and various aromatic diamines. The structures of the monomers were supported by Fourier Transform Infrared (FT-IR), 1H-NMR and 13C-NMR spectral analysis, proving the existence of the benzoxazine ring containing eugenol moiety in its molecular structure. The monomers were polymerized/cured via ring-opening polymerization by heating as indicated by FT-IR and Differential Scanning Calorimetry (DSC). This is confirmed by the disappearance of the peaks due to oxazine ring (942 cm-1). The exothermic peak associated with curing was observed from 170°C to 250°C. The thermal and mechanical properties of the polybenzoxazines were investigated through thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The temperatures corresponding to 5% and 10% weight loss is from 240 to 295°C and from 290 to 340°C, respectively. The completely cured materials could achieve char yields up to 36.5% at 800°C in nitrogen atmosphere. DMA revealed that the glass transition temperatures of PBz-SUL and PBz-PHE were higher than that of PBz-DDS and PBz-OXY.
- Thirukumaran,Shakila,Muthusamy, Sarojadevi
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p. 7959 - 7966
(2014/02/14)
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