Abstract:Resumo: Os espectros no infravermelho próximo (NIR) dos polímeros amorfos poliestireno (PS), poli(metacrilato de metila) (PMMA) e policarbonato (PC) foram estudados. A tentativa de atribuição das bandas harmônicas e de combinação dos modos vibracionais do PS, PMMA e PC foi realizada baseando-se na teoria de modos locais e pelo uso do método matemático de ajuste de curvas. A correção de anarmonicidade e freqüência mecânica foi determinada em um gráfico de Birge-Sponer. Uma correção de anarmonicidade de 57 e 58 … Show more
“…According to the FTIR analysis spectra results, the incorporation of the SiC filler into the PMMA matrix was obtained for all nanocomposites during polymerization process, which can be observed by presence of absorption bands related to silicon carbide and PMMA polymer ( Figure 2) According to the literature, absorption bands at 994-703 cm -1 and 1240-1247 cm -1 , can be attributed to stretching vibrations of Si-C (υSi-C) and to the bending vibration of Si-C (δSi-C), respectively 18 ; in the spectra of the obtained nanocomposite, these absorptions are coupled with PMMA vibrational modes. All nanocomposites (U-PMMA/SiC and T-PMMA/ SiC) presented intense absorption bands at 1724 cm -1 , which were associated to stretching of carbonyl group (C=O), belonging to the PMMA polymer.…”
In this study, polymeric nanocomposites based on poly(methyl methacrylate) (PMMA) and silicon carbide (SiC) nanoparticles were prepared by radical mass polymerization in the presence of filler. Nanoparticles of SiC with and without surface treatment with organosilane were obtained .The nanocomposites were characterized by X-ray fluorescence (XRF), infrared spectroscopy (FTIR), thermogravimetry (TGA) and Field Emission Gun Scanning Electron Microscopy (FEG SEM) with an energy dispersive x-ray spectroscopy (EDS) detector. The produced nanocomposites showed welldispersed SiC incorporation in the PMMA matrix. The results pointed that the surface treatment on SiC fillers was successful on enhancing the interaction between the organic matrix and the inorganic filler.
“…According to the FTIR analysis spectra results, the incorporation of the SiC filler into the PMMA matrix was obtained for all nanocomposites during polymerization process, which can be observed by presence of absorption bands related to silicon carbide and PMMA polymer ( Figure 2) According to the literature, absorption bands at 994-703 cm -1 and 1240-1247 cm -1 , can be attributed to stretching vibrations of Si-C (υSi-C) and to the bending vibration of Si-C (δSi-C), respectively 18 ; in the spectra of the obtained nanocomposite, these absorptions are coupled with PMMA vibrational modes. All nanocomposites (U-PMMA/SiC and T-PMMA/ SiC) presented intense absorption bands at 1724 cm -1 , which were associated to stretching of carbonyl group (C=O), belonging to the PMMA polymer.…”
In this study, polymeric nanocomposites based on poly(methyl methacrylate) (PMMA) and silicon carbide (SiC) nanoparticles were prepared by radical mass polymerization in the presence of filler. Nanoparticles of SiC with and without surface treatment with organosilane were obtained .The nanocomposites were characterized by X-ray fluorescence (XRF), infrared spectroscopy (FTIR), thermogravimetry (TGA) and Field Emission Gun Scanning Electron Microscopy (FEG SEM) with an energy dispersive x-ray spectroscopy (EDS) detector. The produced nanocomposites showed welldispersed SiC incorporation in the PMMA matrix. The results pointed that the surface treatment on SiC fillers was successful on enhancing the interaction between the organic matrix and the inorganic filler.
“…However, it may have been masked by the presence of a small amount of water in the samples [20] and by overtones of ν (CO) PMMA ester group [23] . Bands at 1242 and 1040 cm −1 are a contribution of the C-O-C stretching of an alkyl aryl ether linkage [23] . Bands observed at 1047, 789, 712, 602 cm -1 are associated with o-substituted aromatic rings [18] .…”
Poly(o-methoxyaniline) (POMA) was synthesized by oxidative polymerization of the monomer o-methoxyaniline. POMA/ poly(methyl methacrylate) (PMMA) blends were produced by dissolving both polymers in chloroform (CHCl 3 ).The amount of camphor sulfonic acid (CSA) used as dopant of POMA was different, providing two methods for preparation of the blends. Solutions were analyzed by Fourier transform infrared spectroscopy (FTIR) and then deposited on glass substrate by spin coating for characterization by atomic force microscope (AFM) and current versus voltage (I × V) curves. FTIR spectra of solutions were similar as expected. In the AFM images a reduction and/or loss of globules common in conducting polymers (CP) such as polyaniline (PANI) and its derivatives was observed. Films produced with different amounts of CSA presented distinct, linear and non-linear I × V curves.
“…These spectra were normalized by an internal standard band (here called A 0 ) at 1460 cm -1 (assigned to the PHBV CH 2 deformation, as this band does not change after treatment) and deconvolution applied by the Lorentzian function to adjust the curves and isolate each band with the corresponding area, from the overlapping bands, increasing the spectrum resolution [35] . Table 2 shows a comparison of carbonyl indices in the amorphous and crystalline phases from the original and treated spectra, which were calculated by the areas ratio: A C=O /A 0 bands.…”
SbstractThere is considerable concern about the impact plastic materials have on the environment due to their durability and resistance to degradation. The use of pro-oxidant additives in the polymer films could be a viable way to decrease the harmful effects of these discarded materials. In this study, films of PHBV/PP-co-PE (80/20 w/w) and PHBV/PP-co-PE/add (80/19/1 w/w/w) (with pro-oxidant additive) were employed to verify the influence of the additive on the biodegradation of these films in the soil. These films were obtained by melting the pellets in a press at 180 °C which were buried in soil columns for 3 and 6 months. Some samples were also heated before being buried in soil. The biodegradation is higher for the additive blend buried for 3 months than for the pre-heated blend. After 6 months the blend buried and heated/buried was completely degraded in soil. The effect of the additive, on chain oxidation, is more time-dependant than heat-dependant.
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