Binary Blends Of Poly Research Articles

Poly(vinyl alcohol)/poly(acrylic acid) blends: Miscibility studies by DSC and characterization of their thermally induced hydrogels

AbstractBinary blends of poly(vinyl alcohol) (PVA) with poly(acrylic acid) (PAA) and polyacrylamide (PAAm) were characterized by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and infrared spectroscopy (IR). Molecular weight, blend composition, and heating time at 150°C were the variables used. Results obtained by DSC indicated that PAA/PVA blends are miscible in the full range of composition. Similarly, TGA traces showed that thermal stability was higher for blends than for pure polymers. Blends of PVA with high molecular weight PAA exhibited a hydrogel behavior after drying at relatively low temperature (100°C), whereas blends containing low molecular weight PAA behaved as hydrogels only after they were heated at 150°C. Hydrogel character was increased for these two PVA/PAA blends with the heating time at higher temperature (150°C). IR spectra revealed that esterification took place in these blends after thermally treated at this temperature. In contrast, addition of glyoxal in combination with heating was necessary to produce hydrogels from PAAm/PVA blends. Furthermore, the crosslinking degree of these hydrogels was estimated from their absorbency values by applying the Flory–Rehner equation. © 1993 John Wiley & Sons, Inc.

Miscibility in binary blends of poly(vinylphenol) and aromatic polyesters

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMiscibility in binary blends of poly(vinylphenol) and aromatic polyestersChristine J. T. Landry, Dennis J. Massa, David M. Teegarden, Michael R. Landry, P. Mark Henrichs, Ralph H. Colby, and Timothy E. LongCite this: Macromolecules 1993, 26, 23, 6299–6307Publication Date (Print):November 1, 1993Publication History Published online1 May 2002Published inissue 1 November 1993https://doi.org/10.1021/ma00075a027RIGHTS & PERMISSIONSArticle Views243Altmetric-Citations39LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

The miscibility and phase separation in binary blends of poly(vinyl chloride) with methyl methacrylate/acrylonitrile copolymers

AbstractThe miscibility of poly(vinyl chloride) with poly(methyl methacrylate‐stat‐acrylonitrile) has been studied. Poly(vinyl chloride) is miscible with methyl methacrylate/acrylonitrile copolymers having acrylonitrile contents between 2,0 and 17 wt.‐%. All calculated binary segmental interaction parameters were positive, suggesting immiscibility of the corresponding binary homopolymer blends.

Group contribution method for predicting polymer-polymer miscibility: binary blends of poly(p-vinylphenol) and ester-containing polymers

The ability of the modified Guggenbeim quasichemical (MGQ) group contribution method for predicting polymerpolymer miscibility has been tested in blends composed of poly(p-vinylphenol) (PVPh) and ester-containing polymers (polyacrylates, polymethacrylates, aliphatic polyesters, and ethylen-co-(vinyl acetate) (EVA) copolymers). The model reproduces quite well the experimental miscibility range of these systems and predicts miscibility in the PVPh/poly(dialkyl itaconate) family from poly(dimethyl itaconate) to poly(dioctyl itaconate)

Gas permeability studies on poly(vinyl chloride) based polymer blends intended for medical applications

AbstractPlasticized PVC finds applications in a wide range of medical products. However, plasticizer leaching, known to take place from these conventional materials, is not desirable. A number of approaches to overcome this problem are mentioned in the literature. We suggest pursuing the polyblend approach. Plasticized PVC containing different amounts of plasticizer, binary polyblends of plasticized PVC (PPVC) with acrylonitrile–butadiene rubber (NBR1), and compounded graft polymer of vinyl chloride and ethylene–vinyl acetate copolymer (EVAPVC), and ternary blends of PPVC, NBR1, and EVAPVC, were formulated. In this article, we report our results of studies on water vapor, O2, CO2, and N2 permeabilities. Increased plasticization for PVC was found to increase permeability for water vapor, O2, CO2, and N2. Rise in temperature increased the permeability for water vapor and the change became faster as the materials crossed the region of Tg. A simple model suggested for permeability worked satisfactorily. The binary and ternary blends, based on PPVC, had lower O2, CO2, and N2 permeability. This improvement in property is of great practical significance and interest and the results indicate that PVC‐based polyblends can be investigated further for potential applications in medicine

Miscibility in binary blends of poly(α-methylstyrene) and poly(methyl methacrylate)

Miscibility in binary blends of poly(α-methylstyrene) and poly(methyl methacrylate)

The miscibility and phase separation in binary blends of poly(ethyl methacrylate) with styrene/acrylonitrile copolymers

The miscibility and lower critical solution behaviour of pol(ethyl methacrylate) with poly(styrene-stat-acrylonitrile) have been studied. Poly(ethyl methacrylate) is miscible with styrene/acrylonitrile copolymers having acrylonitrile concents between 9 and 34 wt %. By increasing the size of the pendant group from methyl to ethyl, the repulsive interaction between the methacrylate and acrylonitrile increases, but that between the methacrylate and styrene decreases.

Time-resolved SAXS study of morphological change in a binary blend of poly(iε-caprolactone) and polystyrene oligomer

The process of morphology formation in the blend was studied at various compositions and crystallization temperatures. It is demonstrated that phase separation takes place simultaneously with the crystallization of poly(e-caprolactone) (PCL). The results ate interpreted with a combination of the paracrystalline lattice model developed by Hosemann and the two-phase model developed by Debye and Bueche. The morphological parameters such as long spacing and correlation length are evaluated as a function of time and PCL fraction

Observation of restricted miscibility in binary blends of poly(styrene- stat-acrylonitrile) and poly(α-methyl styrene- stat-acrylonitrile)

Binary blends of two structurally similar copolymers poly(styrene- stat-acrylonitrile) and poly(α-methyl styrene- stat-acrylonitrile) were examined by differential scanning calorimetry. A miscibility map constructed for the system showed that the miscibility range was quite restricted and had a significant molecular weight dependence. The system was characterized by using segmental interaction energy densities calculated from earlier work and it was found that a satisfactory description of the miscibility range could only be obtained if a distinction was made between the ‘intra’ and ‘inter’ segmental interaction parameters. This sensitivity of the interchange energy to the environment of the segment has been observed in other systems. Consequently it may be an important feature in blends whose miscibility ranges are strongly molecular weight dependent, whereas in less sensitive blends the approximation B ij (inter) = B ij (intra) is adequate.

Binary blends of poly(chloromethyl methacrylate) and poly(2-chloroethyl methacrylate) with some aliphatic polyesters

The miscibility behaviour of poly(chloromethyl methacrylate) (PCMMA) and poly(2-chloroethyl methacrylate) (PCEMA) with various aliphatic polyesters was studied by differential scanning calorimetry. PCMMA and PCEMA are miscible with poly(ethylene adipate), poly(butylene adipate), poly(hexamethylene sebacate) (PHS), poly(2,2-dimethyl-1,3-propylene succinate) and poly(2,2-dimethyl-1,3-propylene adipate). In addition, PCMMA is miscible with poly(ethylene succinate) whereas PCEMA is not. Blends of PCEMA with poly(2,2-dimethyl-1,3-propylene sebacate) exhibit upper critical solution temperature behaviour. Interaction parameters for PCMMA/PHS and PCEMA/PHS blends were evaluated from melting point depression analysis.

Ringed Spherulite in Binary Blends of Poly(ε-caprolactone) and ε-Caprolactone-Butadiene Diblock Copolymer

Ringed spherulites were found in binary blends of poly(ε-caprolactone) (PCL) and ε-caprolactone-butadiene diblock copolymer (PCL-b-PB), while the regularly banded structure could not be observed in an oligomeric blend of PCL and polybutadiene (PB). The repeating distance of the ring and its distribution (irregularity) were evaluated as a function of PCL homopolymer (host polymer) fraction, total PCL fraction in the blend, and crystallization temperature. The morphology and melting behavior of the PCL/PCL-b-PB blends were also investigated by small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC). These results suggest that the PCL block of the copolymer takes part in the crystallization of the host polymer and is incorporated into the PCL lamellar crystal. The PB block is, as a result, forced to remain in the amorphous layer between PCL lamellae to lengthen the long spacing (alternating period of the lamella and amorphous layer). This existence of the PB block in the amorphous layer may play an important role in the lamellar twist during the course of crystallization.

FTIR studies of polar interactions in polymer blends

AbstractSpecific interactions in binary blends of poly(vinyl chloride) (PVC) with ethylene–vinyl acetate copolymers (EVA) and ethylene‐methyl acrylate copolymers (EMA) were investigated by observation of band shifts of the carbonyl absorption using ATR‐FTIR spectroscopy at variable temperature. Blends of PVC with EVA and EMA could be prepared as heterogeneous, homogeneous or metastable homogeneous mixtures, depending on the copolymer composition. The miscible systems as well as the heterogeneous ones showed only very small or no band shifts. The metastable blends exhibited shifts of several wave numbers to lower values, which vanished at higher temperatures as the blends demixed. Strong interactions in the metastable blends could be related to good impact properties of the corresponding two‐phase systems.

Morphology formation by combined effect of crystallization and phase separation in a binary blend of poly(iε-caprolactone) and polystyrene oligomer

Etude par SAXS de la morphologie en fonction de la composition du melange et de la temperature de cristallisation de la polycaprolactone. Le systeme presente une separation de phase de type UCST. Les parametres morphologiques (epaisseurs lamellaires et de la couche amorphe) sont evalues en utilisant les modeles de Hosemann-Tsvankin et de Vonk-Kortleve. Les resultats sont interpretes sur la base d'un diagramme de phase contenant les binodales et les points de fusion de la polycaprolactone

The compatibility and transesterification for blends of polyethylene terephthalate)/poly(bisphenol-A carbonate)

Abstract A study has been made of the influence of transesterification on the miscibility in binary blends of poly(ethylene terephthalate) and poly(bisphenol-A carbonate). The blends were melt mixed in the range 260–300°C and studied by differential scanning calorimetry, dynamic mechanic analysis, and by Fourier transform infrared spectrometry. It was found that copolymer produced by a transesterification reaction can enhance the miscibility of this system. The new compositions were uniquely identified by FTIR. Gel permeation chromatography showed that molecular weight decreases were not the origin of miscibility. The ester exchange reaction itself was found to be initiated by the residual catalyst in the commercial polymers selected for study. This has been shown by the absence of reaction after polymer purification by solution and reprecipitation prior to melt mixing.

Apparent phase dissolution at the two-phase region in polymer-polymer mixtures

A binary blend of poly(methyl methacrylate) and poly(styrene-co-acrylonitrile) with 32.2wt% acrylonitrile was found to exhibit lower critical solution temperature (LCST) type phase behaviour. In this binary system, a strange phenomenon was observed: the phase dissolution at the two-phase region above LCST, i.e., when the solution cast film with two-phase structure was annealed at the two-phase region, light scattering intensity decreased and the microscopic image contrast of the two-phase structure became weaker with a longer time of annealing. A computer simulation on the concentration fluctuation by the Cahn-Hilliard type of nonlinear diffusion equation suggested that the phase dissolution is an apparent one caused by the decrease in the composition difference between the coexisting phases along binodal curves attaining the new equilibrium compositions at the annealing temperature.

Intermolecular interactions and phase transition behavior of miscible polymer blends

AbstractA linear equation is proposed to quantify the glass transition behavior of miscible polymer blends in terms of the polymer‐polymer interaction density parameter whose values are obtainable from the melting point depression method. This practical model is successfully applied to four series of binary polyblends containing poly(hydroxy ether) of biphenol A, poly(vinyl chloride), poly(vinylidene fluoride), and poly(2,4‐dimethyl‐1,4‐phenylene oxide) as the common components. Each of these groups of polymer systems exhibits a distinct type of intermolecular interaction that can be characterized by the two coefficients of the model equation. In connection with the present analysis, three novel expressions are introduced for describing the glass transition temperature—composition relations of the polymer systems of interest.

Computer Simulation of Melt Viscoelasticity Functions for Binary Polyblends

Abstract Composition dependence of the polyblends' properties is usually associated with a synergism (the positive deviation from additivity). Using the bicubic spline interpolation technique and the melt viscoelasticity data the effects of shear stress on the location and intensity of the synergism is demonstrated for a set of binary mixtures of commercial polyolefins. Principal patterns of the “transient” and the “set-in” synergisms are identified.

The Ordered Bicontinuous Double Diamond Structure in Binary Blends of Diblock Copolymer and Homopolymer.

ABSTRACTWe report the observation of the ordered bicontinuous double diamond (OBDD) structure in binary blends of poly(styrene-isoprene) diblock copolymer and homopolystyrene. The overall polystyrene volume fraction range is 64 - 67 PSvol% for the OBDD structure in binary blends of a lamellar diblock (SI 27/22) and a homopolymer (14.0 hPS). This composition range is approximately within the polystyrene volume fraction range established for pure diblock copolymers in the strong segregation regime having the OBDD structure. Ordered lamellae are observed at approximately 65 PSvol% when the homopolystyrene molecular weight is greater than the molecular weight of the polystyrene block of the copolymer. This observation is discussed in terms of the decreased degree of mixing between the homopolymer and the corresponding block and the resultant effect on the interfacial curvature.

Effect of rheological parameters on phase morphology of poly blends: A route to computer aided design and development of industrial polyblends

AbstractSet of procedures employing melt viscoelasticity functions for selecting components and composition of the binary polyblends and estimating minor phase domain size is introduced and illustrated with examples. The procedures intended for Computer Aided Manufacture of the polyblends (CAMOBLE) are based on shear stress dependent viscoelasticity ratios, and the selection of the composition exploits stress dependent synergism of the viscoelasticity functions. Also used is auxilary procedure for composition selection is based on verified blending laws accounting for interaction and shear effects. Evaluation of the performance characteristics (“mechanical properties”) is illustrated with a modified Kerner model.

The introduction of a filler and consequent increase in the thermodynamic compatibility of binary polyblends

A reversed gas chromatography method has been used to investigate the influence of a filler on the thermodynamics of interaction (characterized by the thermodynamic interaction parameter χ 23) in incompatible binary polyblends of types polyurethane-high-density PE and PMMA-polybutylmethacrylate. Investigations were carried out over a wide range of concentrations for the polyblends and the filler (kaolin). The introduction of the filler to a blend of two incompatible polymers enhances the thermodynamic stability of the system. In addition, the system becomes thermodynamically compatible in a definite range of temperature. Complex relations between the thermodynamic interaction parameter χ 23 and the filler concentration were observed with various compositions of the PE-polyurethane polyblend. The complex relations are attributed to selective adsorption of one of the polyblend components on the filler surface.