Thermodynamics of mixing of poly(vinyl chloride) and poly(ethylene-co-vinyl acetate) (original) (raw)
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Advances in Polymer Technology, 2014
This paper reports the miscibility and thermal and mechanical properties of solution cast binary blends of poly(ethylene-co-vinyl acetate-co-carbon monoxide) (EVACO) and poly(vinyl chloride) (PVC). The composition of these blends was varied from 10:90 to 90:10 of PVC/EVACO (w/w %). Fourier transform infrared spectroscopy revealed an extensive intermolecular attraction between the blend components, which accounts for their mutual solubility. The differential scanning calorimetry study revealed that the blend components are miscible with each other in all proportions as they exhibited a single glass transition temperature. Tensile strength, moduli, and thermal stabilities of these blends significantly improved with increasing proportion of PVC. C
Thermophysical Properties Of Blend Of Poly ( Vinyl Chloride) With
2015
Abstract: 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.
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.
Macromolecules, 2005
Blends of poly(DL-lactide) (PDLLA) with poly(vinylphenol) (PVPh), obtained by solventcasting and solution/precipitation, have been studied by DSC and FTIR. DSC results obtained in the first heating scan suggest that as-prepared blends are phase separated in nearly pure components. In addition, the initial FTIR spectra of the as-precipitated blends show no sign of specific interactions, which is also consistent with the phase separation. In solution/precipitation blends, the first calorimetric scan shows an exothermic peak attributed to the enthalpy of mixing. To our knowledge, this is the first polymer blend system for which this thermodynamic parameter has been possible to directly measure. The exothermic peak occurs at temperatures just below the T g of PVPh. The consecutive DSC scans show a single Tg for the whole composition range, indicating complete miscibility. The interaction energy density (B) has been calculated and shows a strong dependence on composition. The decrease in B (in terms of absolute value) as the content of PVPh decreases is related to the higher energy consumed to break its strong autoassociation. Phase separation into the neat polymers for the as-prepared blends is attributed to accessibility issues between interacting groups, including steric shielding, group spacing, and chain stiffness, aggravated by blending temperatures below the corresponding T gs. At high temperatures thermal motion increases chain mobility, allowing the development of an intimately mixed single-phase blend. On the other hand, phase separation is observed in solution-cast blends with high PVPh content, certainly due to the ∆ effect, resulting in macroscopic domains that prevent obtaining a homogeneous blend at high temperatures in the absence of a shearing mechanism. Interaction development during heating has been followed by FTIR. Both the hydroxyl and carbonyl stretching regions indicate hydrogen bonding between OH groups of PVPh and CdO groups of PDLLA, suggesting weaker interactions than in other PVPh/polyester systems.
Thermochimica Acta, 2001
The miscibility of poly(styrene) and poly(vinylmethylether) is studied both by measuring the glass transition temperatures of the mixture and with the application of the Flory±Prigogine theory in the approximated form due to Patterson. For these calculations, the enthalpy of mixing of the two polymers is evaluated by measuring the enthalpies of solution of the pure polymers and of the mixture. The trend of the interaction parameters with the temperature for two samples of poly(styrene) of different molecular weight is discussed.
Macromolecular Chemistry and Physics, 1997
Miscibility of poly(ethyloxazo1ine) (PEOX) with poly(viny1 acetate) (PVAC), poly(vinyl alcohol) (PVAL) and poly(viny1 acetate-co-vinyl alcohol) (ACAL copolymers) has been investigated over a wide composition range. In some blends, due to the small difference between the glass transition temperatures of the components, the enthalpic relaxation method was used as miscibility criterion. Differential scanning calorimetry (DSC) results indicate that PEOX is immiscible with PVAC and PVAL but is miscible with ACAL copolymers in a certain range of compositions. The ACALPEOX phase diagram for different copolymer compositions has been determined. The variation of the glass transition temperature with blend composition for miscible systems was found to follow the Kwei equation. Infrared spectroscopy studies of blends reveal the existence of specific interactions via hydrogen bonding between hydroxyl groups in vinyl alcohol units and the carbonyl group in the tertiary amide, which appear to be decisive for miscibility.
2002
The miscibility of blends of poly(vinyl-chloride) (PVC) with poly(ethylene-co-vinyl acetate) (EVA) was investigated through analog calorimetry and a group contribution procedure based on the UNIQUAC model. The group contribution parameters quantifying the pair interactions between the structural features of the above polymers were calculated from experimental excess enthalpies of a series of binary mixtures of chlorocompounds, esters and hydrocarbons. Enthalpy data were also collected for the ternary mixtures (2-chloropropane+ethyl acetate+n-heptane) and (2-chlorobutane + methyl acetate+n-heptane), chosen as possible models for the studied macromolecular mixtures. The miscibility window of the PVC-EVA blends is fairly predicted by the group contribution method. It is also acceptably predicted by the enthalpic behaviour of the first ternary set, but only when the latter is calculated with binary data. A slightly narrower miscibility range is predicted by the binary interaction model. The results of these procedures are compared and the higher reliability of the group contribution procedure is emphasized in terms of its capability to reproduce the exact structure of the macromolecules and the non-univocal choice of the model molecules involved in the analog calorimetry approach.
Macromolecules, 1995
A modified Guggenheim quasichemical method (MGQ) has been applied to calculate enthalpies of mixing in mixtures based on chlorinated polymers such as poly(epichlor0hydrin) (PECH) or poly(viny1 chloride) (PVC). The required parameters have been determined from experimental heats of mixing in mixtures of model compounds. Using the MGQ method, enthalpies of mixing of PECWester containing polymer mixtures and PVC/polyoxide blends have been simulated. In PECWester containing polymer blends, the MGQ method gives an adequate picture of the evolution of the miscibility with the polyester CHJCH2COO ratio. Similarly, in PVC/polyoxide blends, the variation of the heat of mixing along the polyoxide family seems to agree with the miscibility window of these blends. However, in PVC/poly(ethylene oxide) blends, the MGQ method was not able to predict accurately the experimentally observed dependence of the miscibility on the composition.
Macromolecules, 1992
The poly(4-hydroxystyrene) (P4HS)-poly(vinyl acetate) (PVA) system was studied at 170 "C by inverse gas chromatography. Specific retention volumes of several probes in the homopolymers and four blends (0.26,0.38,0.51, and0.76 P4HS volume fractions) were used to measure the thermodynamic interaction between the polymers. The polymer-polymer interaction parameter xzs calculated from the Scott-Flory-Huggins formalism showed an apparent dependence on the probes. This dependence seemed to be related with the strength of the probe interaction with the homopolymers and is believed to result from inappropriate application of the Scott-Flory-Huggins treatment to ternary systems. A method based on the equationof-state theory was applied to eliminate the influence of the probe on xa. Negative values of the polymerpolymer interaction parameter confirm the miscibility of the system, and only a slight variation with the blend composition was found. This variation reveals that the maximum trend in miscibility is achieved at intermediate blend compositions.