Spectroscopic and thermal studies of PS/PVAc blends (original) (raw)
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Physical properties of PVA/PSSNa blends
Journal of Applied Polymer Science, 2003
Blends of conductive polymers with conventional nonconductive ones have, together, the virtues of good electroconductivity and good mechanical properties, whose prospect for electronic industrial application is very good. We prepared poly(vinyl alcohol) (PVA)-sodium polystyrene-sulfonate (PSSNa) blends through aqueous solution casting; the films are flexible and transparent, with electroconductivity that could reach 10 Ϫ5 S/cm. The dependence of the electroconductivity on the weight fraction of PSSNa was found to follow the percolation theory. A general discussion is given on the factors that could influence the percolation threshold and the exponent. The films are stable in a 30% KOH solution and keep their conductivity after 10 days' exposure. Some mechanical properties are measured and the best mixing ratio is obtained for future use.
Evaluation of the structural and optical characters of PVA/PVP blended films
Optical Materials, 2020
The effect of gamma irradiation on the optical and structural properties of poly(vinylalcohol) (PVA)/poly (vinylpyrrolidone) (PVP) blends was investigated in this study. The PVA/PVP films were formulated by mixing and casting method with increasing PVA ratios. The dried films were irradiated at 30 kGy and the impact of gamma irradiation on the characteristics of these films was inspected using FTIR, XRD, SEM and UV-vis techniques in the wavelength range (200-1200) nm. Swanepole method was used to compute the optical constants, optical band gap and complex dielectric constant whereas Wemple-DiDmenico model was applied to develop the optical dispersion parameters E o and E d. Additionally, the high frequency dielectric constant (ε ∞) for all films was recorded. A slight shift in the FT-IR spectra and increase in the transmittance for all films post-irradiation were detected and the XRD analysis depicted the crystalline nature of the PVA/PVP films which was further confirmed by the surface morphology images obtained by the SEM. In conclusion, gamma irradiation and increasing the PVA to PVP ratio improved the optical properties of the films.
FTIR and UV/Vis. Spectroscopy: A Key for Miscibility Investigation of PVC/PMMA Polymer Blend
Fourier transform infrared (FTIR) and UV/Visible (UV/vis.) spectroscopy measurements for Polyvinyl chloride/polymethyl methacrylate (PVC/PMMA) blends prepared in tetrahydrofuran at room temperature were measured. These measured spectra were then used to evaluate the optical energy gap in relation to blend composition. X-ray diffraction (XRD) was used to identify the molecular interaction arising in the mentioned polymer blend films. The peculiar deviation confirms the structural changes in the prepared samples. Scanning electron microscopy shade light on the type of interaction by retracing of the band of Carbonyl group at 1732 cm-1. The change of full width at half maximum and area under carbonyl band in FTIR spectrum was found to change drastically with composition.
Structural, optical, thermal and morphological studies were performed for pure PVA/PVP (50/50) blend and PVA/PVP blend filled with different concentrations of chitosan upto 40 wt% using casting method. The prepared films were investigated by different techniques. All techniques demonstrate the complexation between chitosan and the polymers blend. There were some changes in the IR absorption bands position and its intensities. UV-vis analysis revealed intensity of the shoulder around 273-280 nm increase with increasing chitosan content. Differential scanning calorimetry (DSC) showed thermal stability of the product samples and that has improved after filling chitosan increases. Scanning electron microscope (SEM) images of different concentrations of films revealed that large crystals characteristic of chitosan were also frequently present, when chitosan content increase upto 20 wt%, rough surfaces and crystalline structures are the dominant features. The X-ray diffraction (XRD) showed that the incorporation of chitosan into the polymeric matrix causes decreasing in the crystallinity degree of the samples and this indicates the complexation between the filler and the polymers blend. Thermogravimetric analysis (TGA) is used to study the samples in the temperature range of 30-500 1C. Figures show typical TGA thermograms of weight loss as a function of temperature for the present system.
Thermal and structural studies of poly (vinyl alcohol) and hydroxypropyl cellulose blends
Natural Science, 2012
Polymers and polymeric composites have steadily reflected their importance in our daily life. Blending poly(vinyl alcohol) (PVA) with a potentially useful natural biopolymers such as hydroxypropyl cellulose (HPC) seems to be an interesting way of preparing a polymeric blends. In the present work, blends of PVA/HPC of compositions (100/0, 90/10, 75/25, 50/50, 25/75, and 0/100 wt/wt%) were prepared to be used as bioequivalent materials. Thermal analyses [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)], and X-ray diffraction (XRD) were employed to characterize and reveal the miscibility map and the structural properties of such blend system. The obtained results of the thermal analyses showed variations in the glass transition temperature (T g ) indicating the miscibility of the blend systems. Moreover, the changes in the melting temperature (T m ), shape and area were attributed to the different degrees of crystallinity and the existence of polymer-polymer interactions between PVA and HPC molecules. The X-ray diffraction (XRD) analysis showed broadening and sharpening of peaks at different HPC concentrations with PVA. This indicated changes in the crystallinity/amorphosity ratio, and also suggested that the miscibility between the amorphous components of homo-polymers PVA and HPC is possible. The results showed that HPC doped in PVA film can improve the thermal stability of the film under investigation, leading to interesting technological applications. Figure 6. Variation in X-ray diffraction patterns of PVA/HPC blends: (a) 100/0; (b) 90/10; (c) 75/25; (d) 50/50; (e) 25/75 and (f) 0/100 (wt/wt%).
Polymer Degradation and Stability, 2007
The morphology, thermal and mechanical properties of polystyrene (PS) blends with 2.5e20 wt% of poly(vinyl chloride) (PVC) have been studied. The measurement of the glass transition temperature (T g) from the maxima of tan d data using dynamic mechanical thermal analysis showed that the blends were incompatible and homogenously distributed only within a limited range of PVC contents in PS. The value of the storage modulus was found to increase initially but then decreased with further addition of PVC in the matrix. Distribution of the phases in the virgin and degraded blends was also studied through scanning electron microscopy. The thermogravimetric studies on these blends were carried out under inert atmosphere from ambient to 800 C at different heating rates varying from 2.5 to 20 C/min. The thermal decomposition temperatures of blends were found higher than that of pure PS which indicated the stabilizing effects of PVC on PS. The effect varies with the heating rates and the composition of the blends and the phenomenon has been explained due to changing morphology of the blends with composition and the degradation time which affect the interfacial interaction between the degrading products from the polymer components. The kinetic parameters of the degradation process calculated from a method described by Ozawa have been reported for these blends.
Preparation and Properties of Polyvinyl Alcohol/Polyvinyl Pyrrolidone Blend Films
Applied Mechanics and Materials, 2010
A series of poly(vinyl alcohol) (PVA)/ Poly (vinyl pyrrolidone) (PVP) blend films with different weight ratio of PVA to PVP were prepared by solution-mixing method The morphological structures and characterized of the films were observed via scanning electronic microscopy (SEM), Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR). DSC measurements showed that there was only one Tg for each blend and the values of Tg varied with the PVA content. This implies that the PVP/PVA blend is at least partially compatible. The formation of the hydrogen bonding between the PVP and PVA was identified by the FTIR spectra.
Thermophysical Properties Of Blend Of Poly ( Vinyl Chloride ) With Poly ( Isobornyl Acrylate )
The immiscibility and thermophysical properties of poly(vinyl chloride )(PVC):poly(isobornyl acrylate) (PIBA) (50:50 by weight %) blend, which were prepared by solution method, were studied. The immiscibility was examined by DSC and TGA techniques. The thermophysical properties (thermal conductivity, specific heat capacity and thermal diffusivity) were measured by DSC. Thermophysical properties of PVC:PIBA (50:50 by weight %) blend and dependence on its miscibility were investigated.
Optical Study on Poly(methyl methacrylate)/Poly(vinyl acetate) Blends
International Journal of Photoenergy, 2009
Transparent films of poly(methyl methacrylate)/poly(vinyl acetate) blend with different concentrations were prepared by using solution-cast technique. FT-IR transmission spectra were carried for the samples to detect the influence of UV radiation. In addition, optical absorption measurements were carried out for the samples at room temperature across the 190–900 nm wavelength regions before and after exposure to UV and filtered radiation using xenon arc lamp. The study has been also extended to include the changes in the optical parameters including the band tail width and band gap energies for the samples. Moreover, the refractive index was calculated for the samples from specular reflection and absorption spectrum before and after exposure to UV and filtered radiation.
XRD Study of Binary Polymer Blend of Pmma/Pvac
Blending polymers is an economic method to develop new polymeric materials. Commonly, the final properties of the blend depend on the properties of its polymeric components, its composition, and mainly on the miscibility of the polymers. Poly(methylmethacrylate) and Poly(Vinyl Acetate) are very useful polymers in everyday life. A binary blend of PMMA/PVAc was prepared by solution casting techniques using chloroform as a solvent. The blend system was characterized using X-Ray Diffraction (XRD). X-ray diffraction patterns of binary blends of different composition were studied and discussed in this study.