Theory of coalescence in immiscible polymer blends

Fortelný, Ivan; Kovář, Josef

doi:10.1002/pc.750090204

Cited by 75 publications

(49 citation statements)

References 6 publications

(3 reference statements)

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“…Multiblock copolymers showed higher improvement in impact strength and elongation at break in comparison with the diblock copolymer. Recently, Fortelny and Michá lková 14 studied the effect of the SBS compatibilizer as well as the rate and the time of mixing on the morphology of PP/PS blends with the weight ratio 75/25. They found that an admixture of the SBS copolymer led to the decrease in the average size of the dispersed PS particles, but, interestingly, it did not lead to an increase in the phase structure uniformity.…”

Section: Introductionmentioning

confidence: 99%

Compatibilization of polypropylene/polystyrene blends with poly(styrene-b-butadiene-b-styrene) block copolymer

Radonjič

Musil

Šmit

1998

J. Appl. Polym. Sci.

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ABSTRACT:The compatibilizing effect of the triblock copolymer poly(styrene-b-butadiene-b-styrene) (SBS) on the morphology and mechanical properties of immiscible polypropylene/polystyrene (PP/PS) blends were studied. Blends with three different weight ratios of PP and PS were prepared and three different concentrations of SBS were used for investigations of its compatibilizing effects. Scanning electron microscopy (SEM) showed that SBS reduced the diameter of the PS-dispersed particles as well as improved the adhesion between the matrix and the dispersed phase. Transmission electron microscopy (TEM) revealed that in the PP matrix dispersed particles were complex ''honeycomblike'' aggregates of PS particles enveloped and joined together with the SBS compatibilizer. Wide-angle X-ray diffraction (WAXD) analysis showed that the degree of crystallinity of PP/PS/SBS slightly exceeded the values given by the addition rule. At the same time, addition of SBS to pure PP and to PP/PS blends changed the orientation parameters A 110 and C significantly, indicating an obvious SBS influence on the crystallization process in the PP matrix. SBS interactions with PP and PS influenced the mechanical properties of the compatibilized PP/PS/SBS blends. Addition of SBS decreased the yield stress and the Young's modulus and improved the elongation at yield as well as the notched impact strength in comparison to the binary PP/PS blends. Some theoretical models for the determination of the Young's modulus of binary PP/PS blends were used for comparison with the experimental results. The experimental line was closest to the series model line.

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Section: Introductionmentioning

confidence: 99%

Compatibilization of polypropylene/polystyrene blends with poly(styrene-b-butadiene-b-styrene) block copolymer

Radonjič

Musil

Šmit

1998

J. Appl. Polym. Sci.

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“…The discrepancies between theoretical predictions on structure development and experimental results [4][5][6][7][8][9] are, most likely, due to the complex interfacial properties of, and the mutual interaction between, the polymers. In many cases mutual solubility is considered to be negligible for practical purposes.…”

Section: Introductionmentioning

confidence: 99%

“…In many cases mutual solubility is considered to be negligible for practical purposes. [4][5][6][10][11][12] This seems reasonable since the polymers consist of long molecules, and mixing of those molecules is thermodynamically unfavorable. 13 Moreover, polymers possess a high ͑macroscopic͒ viscosity ͓typically from O͑1-10 3 ͒Pa s͔ and therefore mutual diffusion if present, is expected to be slow ͑the mutual diffusion coefficient is of the order of 10 −13 cm 2 / s and smaller 14 ͒.…”

Section: Introductionmentioning

confidence: 99%

Transient interfacial tension and dilatational rheology of diffuse polymer-polymer interfaces

Peters

Zdravkov

Meijer

2005

The Journal of Chemical Physics

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We demonstrate the influence of molecular weight and molecular weight asymmetry across an interface on the transient behavior of the interfacial tension. The interfacial tension was measured as a function of time for a range of polymer combinations with a broad range of interfacial properties using a pendant/sessile drop apparatus. The results show that neglecting mutual solubility, assumed to be a reasonable approximation in many cases, very often does not sustain. Instead, a diffuse interface layer develops in time with a corresponding transient interfacial tension. Depending on the specific combination of polymers, the transient interfacial tension is found to increase or decrease with time. The results are interpreted in terms of a recently proposed model ͓Shi et al., Macromolecules 37, 1591 ͑2004͔͒, giving relative characteristic diffusion time scales in terms of molecular weight, molecular weight distribution, and viscosities. However, the time scales obtained from this theoretical approach do not give a conclusive trend. Using oscillatory dilatational interfacial experiments the viscoelastic behavior of these diffusive interfaces is demonstrated. The time evolution of the interfacial tension and the dilatational elasticity show the same trend as predicted by the theory of diffuse interfaces, supporting the idea that the polymer combinations under consideration indeed form diffuse interfaces. The dilatational elasticity and the dilatational viscosity show a frequency dependency that is described qualitatively by a simple Fickian diffusion model and quantitatively by a Maxwell model. The characteristic diffusion times provided by the latter show that the systems with thick interfaces ͑tens of microseconds and more͒ can be considered as slower diffusive systems compared to the systems with thinner interfaces ͑a few micrometers in thickness and less͒ can be considered as fast diffusive systems.

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“…The dispersoid size has been found to increase linearly with the portion of the dispersed polymer when the portion is When a blend is left in its molten state, there is no longer a balance between the coalescence and break-up process, but coalescence dominates. The coalescence process resulting from collision between dispersoids due to Brownian motion in immiscible binary blends has been dealt with theoretically by S m o l u c h o w~k i .~~-~~ Furthermore, for a system of dispersed monospherical particles, it was found by Fortelny and Kovar26,27 that the inverse of the square root of the number of particles per unit volume (n) is proportional to the square root of the time ( t ) for which the coalescence has occurred such that where no is the initial number of spheres per unit area, k the Boltzmann constant, T the melt temperature, 7 viscosity of matrix polymer, and 4 the volume fraction of the dispersed polymer component.…”

mentioning

confidence: 98%

Study of dispersion morphologies of isotactic polypropylene and linear low density polyethylene blends by scanning electron microscopy

Liu

Truss

1996

J. Appl. Polym. Sci.

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SYNOPSISIsotactic polypropylene (iPP) and linear low-density polyethylene (LLDPE) blends with five different component ratios were prepared by melt mixing. The blends were subsequently remelted a t 200°C for 1, 2, 3, 5, 8, 12, 20 min, and 2 h. The morphologies of the heattreated and as-blended materials were studied on the cryogenically fractured surfaces of these blends by scanning electron microscopy (SEM). It was found that the morphologies of the blends with equal component ratio were highly unstable in remelting, while those blends with the lowest minor component ratios were the most stable ones, showing a growth in the size of the dispersed particles. 0 1996 John Wiley & Sons, Inc.

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Theory of coalescence in immiscible polymer blends

Cited by 75 publications

References 6 publications

Compatibilization of polypropylene/polystyrene blends with poly(styrene-b-butadiene-b-styrene) block copolymer

Compatibilization of polypropylene/polystyrene blends with poly(styrene-b-butadiene-b-styrene) block copolymer

Transient interfacial tension and dilatational rheology of diffuse polymer-polymer interfaces

Study of dispersion morphologies of isotactic polypropylene and linear low density polyethylene blends by scanning electron microscopy

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