Modified models of polymer phase separation

Zhou, Douglas; Zhang, Pingwen; Weinan, E

doi:10.1103/physreve.73.061801

Cited by 44 publications

(95 citation statements)

References 20 publications

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“…Tanaka and Araki 19,20 proposed that the quick hydrodynamic reduction of the interfacial area might spontaneously destabilize the phase separated macroscopic domains and induce viscoelastic phase separation. Zhou et al 21 recently reported volume shrinkage, phase inversion, and final complex phase morphologies are caused by diffusional asymmetry of the consistent molecules. It was reported that complex phase separation may take place due to unusual fast growth of domains in the matrix and chemical reaction between the binary mixtures.…”

Section: Introductionmentioning

confidence: 98%

Complex Phase Separation in Poly(acrylonitrile−butadiene−styrene)-Modified Epoxy/4,4′-Diaminodiphenyl Sulfone Blends: Generation of New Micro- and Nanosubstructures

et al. 2009

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The epoxy system containing diglycidyl ether of bisphenol A and 4,4'-diaminodiphenyl sulfone is modified with poly(acrylonitrile-butadiene-styrene) (ABS) to explore the effects of the ABS content on the phase morphology, mechanism of phase separation, and viscoelastic properties. The amount of ABS in the blends was 5, 10, 15, and 20 parts per hundred of epoxy resin (phr). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to investigate the final morphology of ABS-modified epoxy blends. Scanning electron microscopic studies of 15 phr ABS-modified epoxy blends reveal a bicontinuous structure in which both epoxy and ABS are continuous, with substructures of the ABS phase dispersed in the continuous epoxy phase and substructures of the epoxy phase dispersed in the continuous ABS phase. TEM micrographs of 15 phr ABS-modified epoxy blends confirm the results observed by SEM. TEM micrographs reveal the existence of nanosubstructures of ABS in 20 phr ABS-modified epoxy blends. To the best of our knowledge, to date, nanosubstructures have never been reported in any epoxy/thermoplastic blends. The influence of the concentration of the thermoplastic on the generated morphology as analyzed by SEM and TEM was explained in detail. The evolution and mechanism of phase separation was investigated in detail by optical microscopy (OM) and small-angle laser light scattering (SALLS). At concentrations lower than 10 phr the system phase separates through nucleation and growth (NG). However, at higher concentrations, 15 and 20 phr, the blends phase separate through both NG and spinodal decomposition mechanisms. On the basis of OM and SALLS, we conclude that the phenomenon of complex substructure formation in dynamic asymmetric blends is due to the combined effect of hydrodynamics and viscoelasticity. Additionally, dynamic mechanical analysis was carried out to evaluate the viscoelastic behavior of the cross-linked epoxy/ABS blends. Finally, apparent weight fractions of epoxy and ABS components in epoxy- and ABS-rich phases were evaluated from T(g) analysis.

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Section: Introductionmentioning

confidence: 98%

Complex Phase Separation in Poly(acrylonitrile−butadiene−styrene)-Modified Epoxy/4,4′-Diaminodiphenyl Sulfone Blends: Generation of New Micro- and Nanosubstructures

et al. 2009

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“…In this regard, Equation 10 can be reduced into a simple mathematical form by setting without affecting the minimization of the free energy. Thus, the interaction parameter also accordingly scales up into the widely reported theoretical range where results in a single well and leads to a double well [23,24,26,32]. As for the dilution parameter , the values can be preliminarily estimated based on the reported swelling ratio values of polymer in PMB.…”

Section: Simulation Environment and Parametersmentioning

confidence: 99%

“…In order to obtain the expression of the free energy, a double-well potential for PMB system can be determined on the basis of the Flory-Huggins free energy of mixing [18][19][20][23][24][25][26]. The Flory-Huggins theory was originally proposed for polymer solutions by taking into account their differences with an ideal solution, i.e.…”

Section: Figure 1 Phase Diagram (A) and Free Energy Curves (B)mentioning

confidence: 99%

Modelling and numerical simulation of phase separation in polymer modified bitumen by phase-field method

Zhu

Balieu

et al. 2016

Materials & Design

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In this paper, a phase-field model with viscoelastic effects is developed for polymer modified bitumen (PMB) with the aim to describe and predict the PMB storage stability and phase separation behaviour. The viscoelastic effects due to dynamic asymmetry between bitumen and polymer are represented in the model by introducing a composition-dependent mobility coefficient. A double-well potential for PMB system is proposed on the basis of the Flory-Huggins free energy of mixing, with some simplifying assumptions made to take into account the complex chemical composition of bitumen. The model has been implemented in a finite element software package for pseudo-binary PMBs and calibrated with experimental observations of three different PMBs. Parametric studies have been conducted. Simulation results indicate that all the investigated model parameters, including the mobility and gradient energy coefficients, interaction and dilution parameters, have specific effects on the phase separation process of an unstable PMB. In addition to the unstable cases, the model can also describe and predict stable PMBs. Moreover, the phase inversion phenomenon with increasing polymer content in PMBs is also well reproduced by the model. This model can be the foundation of an applicable numerical tool for prediction of PMB storage stability and phase separation behaviour.

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“…Phase separation in polymer systems can exhibit a phase inversion. [41][42][43] The phase inversion occurs when the PVME-rich sponge-like structure is broken and the PVME-rich phase changes from being continuous (Fig. 4, layer 4) to being discontinuous (layer 6).…”

Section: Optical Microscopy-morphology Investigationmentioning

confidence: 99%

Probing the Micro-Phase Separation of Thermo-Responsive Amphiphilic Polymer in Water/Ethanol Solution

Labuta¹,

Hill²,

Hanyková³

et al. 2010

J. Nanosci. Nanotech.

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The temperature-induced coil-globule transition (micro-phase separation) in water/ethanol solutions of poly(vinyl methyl ether) was studied using NMR spectroscopy, differential scanning calorimetry, optical microscopy and dynamic light scattering. NMR sequence based on spin-echo was introduced in order to determine lower critical solution temperature with high accuracy. Variation in DSC profiles and enthalpy increments depending on ethanol concentration in a water/ethanol mixture was found. Evolution of morphology pattern during heating-cooling cycle was observed using optical microscopy. At lower PVME concentration the globule size distribution was determined using digital image processing. Relative number and relative mass size distributions of globules in a dilute sample were measured by differential scanning calorimetry and subsequently compared with those obtained by optical microscopy.

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Modified models of polymer phase separation

Cited by 44 publications

References 20 publications

Complex Phase Separation in Poly(acrylonitrile−butadiene−styrene)-Modified Epoxy/4,4′-Diaminodiphenyl Sulfone Blends: Generation of New Micro- and Nanosubstructures

Complex Phase Separation in Poly(acrylonitrile−butadiene−styrene)-Modified Epoxy/4,4′-Diaminodiphenyl Sulfone Blends: Generation of New Micro- and Nanosubstructures

Modelling and numerical simulation of phase separation in polymer modified bitumen by phase-field method

Probing the Micro-Phase Separation of Thermo-Responsive Amphiphilic Polymer in Water/Ethanol Solution

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