Instantaneous Phase Separation at the Contact Surface in Compression Molding of Immiscible Polymer Blend

2010 ◽  
Author(s):  
Wei Zhang ◽  
Min Li ◽  
Sarang Deodhar ◽  
Donggang Yao ◽  
Jack G. Zhou
Keyword(s):  
Phase Separation ◽  
Compression Ratio ◽  
Contact Surface ◽  
Phase Structure ◽  
Compression Molding ◽  
Continuous Phase ◽  
Structure Evolution ◽  
Compression Rate ◽  
Mold Surface ◽  
Immiscible Polymer

Immiscible polymer blends with a co-continuous phase structure (CPS) can yield synergistic material properties. In this study, a 50/50 wt% PLA/PS blend with CPS was used as a model system to explore the influence of compression molding conditions (including compression rate, compression ratio, and mold surface characteristics) on the final phase structure of the molded part. The microscopic characterization clearly demonstrated the instantaneous formation of a PLA rich layer at the mold contact surface when a high compression ratio and fast compression rate were applied during molding. CFD simulations were performed to numerically study the effects of compression on phase structure evolution in binary blends. If harnessed appropriately, this phase separation process may be utilized for creating innovative material structures.

scholarly journals Description of the Droplet Size Evolution in Flowing Immiscible Polymer Blends

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 761 ◽  
Author(s):  
Fortelný ◽  
Jůza
Keyword(s):  
Polymer Blends ◽  
Droplet Size ◽  
Phase Structure ◽  
Droplet Breakup ◽  
Structure Evolution ◽  
Immiscible Polymer Blends ◽  
Collision Efficiency ◽  
Immiscible Polymer ◽  
Size Evolution ◽  
Analytic Expressions

Control of the phase structure evolution in flowing immiscible polymer blends during their mixing and processing is fundamental for tailoring of their performance. This review summarizes present state of understanding and predictability of the phase structure evolution in flowing immiscible polymer blends with dispersed structure. Results of the studies of the droplet breakup in flow, important for determination of the droplet breakup frequency and of the size distribution of the daughter droplets, are reviewed. Theories of the flow-induced coalescence providing equations for collision efficiency are discussed. Approximate analytic expressions reliably describing dependence of the collision efficiency on system parameters are presented. Available theories describing the competition between the droplet breakup and coalescence in flow are summarized and approximations used in their derivation are discussed. Problems with applicability of available theories on prediction of the droplet size evolution during mixing and processing of immiscible polymer blends, which have not been broadly discussed so far, are addressed.

Phase Structure Evolution During Compression Molding of Compatibilized Polymer Blends

2012 ◽  
Vol 51 (10) ◽  
pp. 2026-2033 ◽  
Author(s):  
Ivan Fortelný ◽  
Bojan Dimzoski ◽  
Danuše Michálková
Keyword(s):  
Polymer Blends ◽  
Phase Structure ◽  
Compression Molding ◽  
Structure Evolution

Surface phase structure evolution of the fcc MoC (001) surface in steam reforming atmosphere: systematic kinetic and thermodynamic investigations

2022 ◽  
Author(s):  
Changqing Chu ◽  
Chao Li ◽  
Xue Liu ◽  
Hang Zhao ◽  
Changning Wu ◽  
...  
Keyword(s):  
Steam Reforming ◽  
Phase Structure ◽  
Structure Evolution ◽  
Surface Phase

The kinetic and thermodynamic aspects of the surface phase structure evolution on a fcc MoC (001) surface under H2O/H2-rich atmosphere typical in steam reforming processes were systematically studied by periodic...

scholarly journals Phase Separation Behavior and System Properties of Aqueous Two-Phase Systems with Polyethylene Glycol and Different Salts: Experiment and Correlation

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Haihua Yuan ◽  
Yang Liu ◽  
Wanqian Wei ◽  
Yongjie Zhao
Keyword(s):  
Phase Separation ◽  
Sodium Citrate ◽  
Line Length ◽  
Continuous Phase ◽  
Two Phase ◽  
Separation Rate ◽  
Aqueous Two Phase Systems ◽  
Phase Systems ◽  
System Properties ◽  
Tie Line

The phase separation behaviors of PEG1000/sodium citrate, PEG4000/sodium citrate, PEG1000/ammonium sulfate, and PEG4000/ammonium sulfate aqueous two-phase systems were investigated, respectively. There are two distinct situations for the phase separation rate in the investigated aqueous two-phase systems: one state is top-continuous phase with slow phase separation rate and strong bottom-continuous phase with fast phase separation rate and weak volume ratio dependence. The system properties such as density, viscosity, and interfacial tension between top and bottom phases which have effects on the phase separation rate of aqueous two-phase systems were measured. The property parameter differences between the two phases increased with increasing tie line length and then improved the phase separation rate. Moreover, a modified correlation equation including the phase separation rate, tie line length, and physical properties of the four aqueous two-phase systems has been proposed and successfully tested in the bottom-continuous phase, whose coefficients were estimated through regression analysis. The predicted results of PEG1000/sodium citrate aqueous two-phase systems were verified through the stationary phase retention in the cross-axis countercurrent chromatography.

scholarly journals Destabilization and phase separation of particle suspensions in emulsions

Soft Matter ◽  
2020 ◽  
Vol 16 (47) ◽  
pp. 10697-10706
Author(s):  
Blandine Feneuil ◽  
Atle Jensen ◽  
Andreas Carlson
Keyword(s):  
Phase Separation ◽  
Continuous Phase ◽  
Particle Suspensions

The presence of particles in an emulsion affects the drainage direction and velocity of the continuous phase. We observe experimentally and numerically that particles can either stabilize the emulsion or enhance drainage.

Time evolution of phase structure and corresponding mechanical properties of iPP/PEOc blends in the late-stage phase separation and crystallization

Polymer ◽  
2007 ◽  
Vol 48 (21) ◽  
pp. 6395-6403 ◽  
Author(s):  
Yongyan Pang ◽  
Xia Dong ◽  
Ying Zhao ◽  
Charles C. Han ◽  
Dujin Wang
Keyword(s):  
Mechanical Properties ◽  
Phase Separation ◽  
Time Evolution ◽  
Late Stage ◽  
Phase Structure

MESOSCOPIC SIMULATION ON THE PHASE STRUCTURE OF PLURONIC P105 AQUEOUS SOLUTION

2010 ◽  
Vol 09 (04) ◽  
pp. 767-783 ◽  
Author(s):  
SHIJIN DONG ◽  
HAITAO ZHANG ◽  
XUEJUN CUI ◽  
ZHENYING SUI ◽  
JIA XU ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Phase Separation ◽  
Ethylene Oxide ◽  
Phase Structure ◽  
Chain Model ◽  
Growth Mechanisms ◽  
Mesoscopic Simulation ◽  
Aggregate Properties ◽  
Spherical Micelles ◽  
Simulation Results

The mesoscopic dynamic simulation (MesoDyn) has been carried out to investigate the phase structure and the aggregate properties of triblock copolymers (ethylene oxide)37 (propylene oxide)56 (ethylene oxide)37 (P105) in aqueous solution. A Gaussian chain model is successfully built according to the equivalent chain method and the Flory–Huggins interaction parameters, χ, used for determining the repulsions between different chain segments are computed. Simulation results show that P105 can form several microstructures including spherical micelles, ellipsoid micellar cluster, worm-like micelles, defective bicontinuous phase, and bicontinuous phase with increasing concentration. A special transition phase structure of P105 is found in the spherical micellar region. The dynamic evolution processes of spherical micelles are investigated by observing the induction time before phase separation and the changing of isosurface during phase separation. The influence of P105 concentration on the density of micelles at equilibrium state is also discussed, which shows that the increase of P105 concentration will lead to the decrease of micelles' amount. Two kinds of growth mechanisms during phase separation are discussed by MesoDyn simulation.

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