Fourier transform infrared spectroscopy

About: Fourier transform infrared spectroscopy is a research topic. Over the lifetime, 48250 publications have been published within this topic receiving 1134369 citations.

Effect of annealing on phase transition in poly(vinylidene fluoride) films prepared using polar solvent

Abstract: The γ-phase poly (vinylidene fluoride) (PVDF) films are usually prepared using dimethyl sulfoxide (DMSO) solvent, regardless of preparation temperature. Here we report the crystallization of both α and γ-phase PVDF films by varying preparation temperature using DMSO solvent. The γ-phase PVDF films were annealed at 70, 90, 110, 130 and 160°C for five hours. The changes in the phase contents in the PVDF at different annealing conditions have been described. When thin films were annealed at 90°C for 5 h, maximum percentage of β-phase appears in PVDF thin films. The γ-phase PVDF films completely converted to α-phase when they were annealed at 160°C for 5 h. From X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), differential scanning calorimetry (DSC) and Raman studies, it is confirmed that the PVDF thin films, cast from solution and annealed at 90°C for 5 h, have maximum percentage of β-phase. The β-phase PVDF shows a remnant polarization of 4.9 μC/cm2 at 1400 kV/cm at 1 Hz.

Crystallization Behavior of Poly(l-lactic acid) Nanocomposites: Nucleation and Growth Probed by Infrared Spectroscopy

Abstract: Time-lapsed Fourier transform infrared (FTIR) spectroscopy was employed to probe chain conformational changes during the isothermal crystallization of poly(l-lactic acid), PLLA, and its nanocomposites from the melt. To study the effect of clay exfoliation extent on the crystallization behavior of PLLA, intercalated and exfoliated nanocomposites were fabricated by solution casting two commercially available organoclays with different degrees of matrix miscibility. By solely varying the degree of miscibility between the organic modifier and the polymer matrix, fully intercalated and exfoliated nanocomposites were obtained. This system allowed us to systematically investigate the effect of degree of clay exfoliation on the chain conformational changes during the crystallization process. In the case of neat PLLA, interchain interactions preceded intrachain interactions during the crystallization. Conversely, the exfoliated nanocomposites exhibited an opposite behavior in that 103 helix formation and backbone ...

Effect of Solvent on Titania Particle Formation and Morphology in Thermal Hydrolysis of TiCl4

Abstract: Titania powders were synthesized by the thermal hydrolysis of titanium tetrachloride with the yield of above 85% in a mixed solvent of n-propanol and water. The morphology of the precipitates was controlled by adjusting the volume ratio of n-propanol to water (RH ratio) of the mixed solvent. Precipitates obtained with an RH ratio of 0 were fine, and highly agglomerated. In contrast, an RH ratio of 3 resulted in precipitates consisting of uniform and discrete particles. According to observations of the zeta potentials of precipitates and the dielectric constants of solvents, the discrete particles obtained with an RH ratio of 3 resulted from the low zeta potential and dielectric constant. The result of Fourier transform infrared (FTIR) spectroscopy showed the chemical interaction of particle surface with the solvent alcohol, which decreased the zeta potential of precipitates with an increase of RH ratio. Adding hydroxypropyl cellulose (HPC) as a steric dispersant made it possible to reduce the size of particles to the submicrometer range. Effects of the solvent on the formation and morphology of the resulting particles were investigated.