A study on polymer blending microrheology: Part IV. The influence of coalescence on blend morphology origination

Elmendorp, J. J.; Vegt, A.K. van der

doi:10.1002/pen.760261908

Cited by 210 publications

(134 citation statements)

References 12 publications

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“…More specifically, the local collision frequency linearly increases with the offset in the velocity gradient direction [13]. To take this into account, the coalescence efficiency is not defined as the maximum initial offset up to which coalescence occurs, but as the square of this maximum offset [13,50]. Since in the confined case there is also a lower critical initial offset below which coalescence is not possible, the coalescence efficiency for the confined case can be extended to:…”

Section: Coalescence Efficiencymentioning

confidence: 99%

The effect of geometrical confinement on coalescence efficiency of droplet pairs in shear flow

Bruyn

Cardinaels

Moldenaers

2013

Journal of Colloid and Interface Science

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 1The effect of geometrical confinement on coalescence efficiency of droplet pairs in shear flow AbstractDroplet coalescence is determined by the combined effect of the collision frequency and the coalescence efficiency of colliding droplets. In the present work, the effect of geometrical confinement on coalescence efficiency in shear flow is experimentally investigated by means of a counter rotating parallel plate device, equipped with a microscope. The model system consisted of Newtonian droplets in a Newtonian matrix. The ratio of droplet diameter to plate spacing ( ) is varied between 0.06 and 0.42, thus covering bulk as well as confined conditions. Droplet interactions are investigated for the complete range of offsets between the droplet centers in the velocity gradient direction. It is observed that due to confinement coalescence is possible up to higher initial offsets. On the other hand, confinement also induces a lower boundary for the initial offset, below which the droplets reverse during their interaction, thus rendering coalescence impossible.Numerical simulations in 2D show that the latter phenomenon is caused by recirculation flows at the front and rear of confined droplet pairs. The lower boundary is independent of , but increases with increasing confinement ratio and droplet size. The overall coalescence efficiency is significantly larger in confined conditions as compared to bulk conditions.

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Section: Coalescence Efficiencymentioning

confidence: 99%

The effect of geometrical confinement on coalescence efficiency of droplet pairs in shear flow

Bruyn

Cardinaels

Moldenaers

2013

Journal of Colloid and Interface Science

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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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“…Although this modification of the PC/PVDF interface by PMMA has a favorable effect on both the interfacial tension and the interfacial adhesion, further improvement of this situation is expected to result from the interfacial formation of a graft copolymer between PC and PMMA. Block and graft copolymers at polyblend interface are indeed known to improve the interfacial adhesion and to inhibit phase coalescence [24][25][26].…”

Section: Morphologymentioning

confidence: 99%

Reactive compatibilization of PC/PVDF polymer blends by zinc carboxylate containing poly(methylmethacrylate) ionomers

Moussaif¹,

Pagnoulle²,

Jérôme³

2000

Polymer

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Polycarbonate (PC) has been reacted with a random copolymer of methylmethacrylate and 6 mol% of acrylic acid (poly(MMA-co-AA)) and with this copolymer neutralized (totally or not) by Zn cations. When conducted in solution at 240°C, the reaction leads to the grafting of PC onto the copolymer neutralized or not. In the melt at 235°C, the grafting reaction occurs only when the copolymer is at least partly neutralized. Whatever the experimental conditions (solution or bulk), PMMA does not react with PC, which confirms that the acidolysis of PC is at the origin of the grafting reaction.Poly(vinylidene fluoride) (PVDF) and PC have been melt blended at 235°C in the presence of the poly(MMAco-AA) copolymer totally neutralized or not by Zn cations, the purpose being the reactive formation of PMMAg-PC copolymer that would act as compatibilizer for the PC/PVDF blend. The phase morphology and the mechanical properties of the compatibilized PC/PVDF blends have been compared with the parent non-reactive polyblends. Compared to the modification of PVDF by 20 wt% of PMMA, the use of 20 wt% of the partly neutralized poly(MMA-co-AA) copolymer decreases further the average size of the dispersed phase, enhances its adhesion to the matrix, and results in a considerable increase of the elongation at break. The beneficial effect of zinc carboxylate in the PMMA copolymer is explained by the grafting of PC onto PMMA at the interface.

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A study on polymer blending microrheology: Part IV. The influence of coalescence on blend morphology origination

Cited by 210 publications

References 12 publications

The effect of geometrical confinement on coalescence efficiency of droplet pairs in shear flow

The effect of geometrical confinement on coalescence efficiency of droplet pairs in shear flow

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

Reactive compatibilization of PC/PVDF polymer blends by zinc carboxylate containing poly(methylmethacrylate) ionomers

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