scholarly journals Phase Equilibrium and Interdiffusion in Blends of Polystyrene with Polyacrylates

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2283
Author(s):  
Uliana V. Nikulova ◽  
Anatoly E. Chalykh
Keyword(s):  
Diffusion Coefficients ◽  
Phase State ◽  
Pair Interaction ◽  
Side Chain ◽  
Matrix Structure ◽  
State Diagrams ◽  
The Matrix ◽  
Temperature Dependences ◽  
Interferometry Method ◽  
Interdiffusion Coefficients

The solubility and interdiffusion of polystyrene (PS) with polymethyl acrylate (PMA), polyethyl acrylate (PEA), polybutyl acrylate (PBA), and polyethylhexyl acrylate (PEHA) have been studied by the optical interferometry method. Phase state diagrams are plotted. It is shown that they are characterized by the upper critical solution temperatures (UCST), which are localized in the temperature range above 450 K. Pair interaction parameters and their temperature dependences are determined and analyzed. Extrapolation of the temperature dependence of the interaction parameter was used to construct the dome of binodal curves and determine the spinodal curves in the framework of the Flory–Huggins theory. The diffusion coefficients of polystyrene into polyacrylates and polyacrylates into polystyrene are calculated. The dependences of the interdiffusion coefficients on the concentration, temperature, polystyrene molecular weight, and the number of carbons in the side chain of polyacrylate are analyzed. The numerical values of the interdiffusion coefficients of PS-1 into polyacrylates at 433 K change as −8.5 → −6.7 → −6.4 in the homologous series PMA → PEA → PBA. The coefficients of friction are calculated and the effect of change in the matrix structure on the diffusion of polystyrene in them is estimated.

scholarly journals Role of different factors affecting interdiffusion in Cu(Ga) and Cu(Si) solid solutions

2014 ◽  
Vol 470 (2161) ◽  
pp. 20130464 ◽  
Author(s):  
Sangeeta Santra ◽  
Hongqun Dong ◽  
Tomi Laurila ◽  
Aloke Paul
Keyword(s):  
Solid Solutions ◽  
Diffusion Coefficients ◽  
Tracer Diffusion ◽  
Impurity Diffusion ◽  
Factors Affecting ◽  
The Matrix ◽  
Bond Strengths ◽  
Interdiffusion Coefficients ◽  
Formation Energies

A detailed diffusion study was carried out on Cu(Ga) and Cu(Si) solid solutions in order to assess the role of different factors in the behaviour of the diffusing components. The faster diffusing species in the two systems, interdiffusion, intrinsic and impurity diffusion coefficients, are determined to facilitate the discussion. It was found that Cu was more mobile in the Cu–Si system, whereas Ga was the faster diffusing species in the Cu–Ga system. In both systems, the interdiffusion coefficients increased with increasing amount of solute (e.g. Si or Ga) in the matrix (Cu). Impurity diffusion coefficients for Si and Ga in Cu, found out by extrapolating interdiffusion coefficient data to zero composition of the solute, were both higher than the Cu tracer diffusion coefficient. These observed trends in diffusion behaviour could be rationalized by considering: (i) formation energies and concentration of vacancies, (ii) elastic moduli (indicating bond strengths) of the elements and (iii) the interaction parameters and the related thermodynamic factors. In summary, we have shown here that all the factors introduced in this paper should be considered simultaneously to understand interdiffusion in solid solutions. Otherwise, some of the aspects may look unusual or even impossible to explain.

scholarly journals Фазовая диаграмма состояния и межфазные характеристики в бинарной наносистеме

2018 ◽  
Vol 60 (1) ◽  
pp. 180
Author(s):  
М.А. Шебзухова ◽  
А.А. Шебзухов
Keyword(s):  
Interfacial Tension ◽  
Size Effects ◽  
Interfacial Layer ◽  
Phase State ◽  
Calculated Data ◽  
Size Composition ◽  
Size Dependent ◽  
State Diagrams ◽  
Monodispersed Particles ◽  
The Matrix

AbstractThe size effects on the composition of coexisting phases, the interfacial layer between them, and the interfacial tension in a binary system composed of a matrix and the monodispersed particles of arbitrary (including nanoscale) size are described in the context of a Gibbs method for dispersed systems. Obtaining the relevant relationships has allowed plotting the size-dependent phase state diagrams for a Cr–Ti system with a point of equal concentrations with a minimum. The coefficients of size composition of the nanoparticles and the matrix, as well as those of interfacial tension under the isobaric and isothermal conditions, are calculated at different degree of dispersion. The calculated data coincide with the experimental ones.

Inverse T-Sample Method of Determination of the Interdiffusion Coefficients in the Cu-Ni-Sn System

2005 ◽  
Vol 237-240 ◽  
pp. 224-229
Author(s):  
Yu.A. Lyashenko ◽  
V.V. Bogdanov
Keyword(s):  
Diffusion Coefficients ◽  
Lateral Diffusion ◽  
Ternary Diffusion ◽  
Special Configuration ◽  
Intermediate Phases ◽  
Ternary Diffusion Couple ◽  
The Matrix ◽  
Sample Method ◽  
Interdiffusion Coefficients

A method of the determining of the mutual diffusion coefficients in ternary intermediate phases is suggested. Methodology for determination of the interdiffusion coefficients of phases formed in a ternary diffusion couple in T-sample configuration is presented. The method requires only one annealing of the T-sample and makes it possible to calculate the matrix of the diffusion coefficients in the (CuNi)6Sn5 and Cu3Sn ternary intermediate phases under low temperature. The concentration profiles and electron micrograph of the diffusion zone was obtained in the ternary Cu-Ni-Sn system annealed for 64 hours under 200°C. Phase competition in this ternary system with special configuration of T-sample leads to lateral diffusion of Cu, to formation (CuNi)6Sn5 compound between Ni-Sn side and to suppression of other NixSny intermediate phases.

Formation of Persistent Slip Band in Fatigued Copper Single Crystals

1982 ◽  
Vol 40 ◽  
pp. 470-471
Author(s):  
N. Y. Jin
Keyword(s):  
Volume Fraction ◽  
Fatigue Cracks ◽  
Wall Structure ◽  
Matrix Structure ◽  
Dislocation Dipole ◽  
Slip Bands ◽  
Persistent Slip Bands ◽  
The Matrix ◽  
Hard Shell ◽  
Copper Single Crystals

Localised plastic deformation in Persistent Slip Bands(PSBs) is a characteristic feature of fatigue in many materials. The dislocation structure in the PSBs contains regularly spaced dislocation dipole walls occupying a volume fraction of around 10%. The remainder of the specimen, the inactive "matrix", contains dislocation veins at a volume fraction of 50% or more. Walls and veins are both separated by regions in which the dislocation density is lower by some orders of magnitude. Since the PSBs offer favorable sites for the initiation of fatigue cracks, the formation of the PSB wall structure is of great interest. Winter has proposed that PSBs form as the result of a transformation of the matrix structure to a regular wall structure, and that the instability occurs among the broad dipoles near the center of a vein rather than in the hard shell surounding the vein as argued by Kulmann-Wilsdorf.

scholarly journals Pressure dependence of Si diffusion in γ-Fe

2020 ◽  
Vol 105 (3) ◽  
pp. 319-324
Author(s):  
Noriyoshi Tsujino ◽  
Andreea Mârza ◽  
Daisuke Yamazaki
Keyword(s):  
Plastic Deformation ◽  
Pressure Dependence ◽  
Diffusion Coefficients ◽  
Inner Core ◽  
Absolute Temperature ◽  
Homologous Temperature ◽  
Temperature Scaling ◽  
Constant E ◽  
Temperature Dependences ◽  
Earth’S Inner Core

Abstract The pressure dependence of Si diffusion in γ-Fe was investigated at pressures of 5–15 GPa and temperatures of 1473–1673 K using the Kawai-type multi-anvil apparatus to estimate the rate of mass transportation for the chemical homogenization of the Earth's inner core and those of small terrestrial planets and large satellites. The obtained diffusion coefficients D were fitted to the equation D = D0 exp[−(E* + PV*)/(RT)], where D0 is a constant, E* is the activation energy, P is the pressure, V* is the activation volume, R is the gas constant, and T is the absolute temperature. The least-squares analysis yielded D0 = 10-1.17±0.54 m2/s, E* = 336 ± 16 kJ/mol, and V* = 4.3 ± 0.2 cm3/mol. Moreover, the pressure and temperature dependences of diffusion coefficients of Si in γ-Fe can also be expressed well using homologous temperature scaling, which is expressed as D = D0exp{–g[Tm(P)]/T}, where g is a constant, Tm(P) is the melting temperature at pressure P, and D0 and g are 10-1.0±0.3 m2/s and 22.0 ± 0.7, respectively. The present study indicates that even for 1 billion years, the maximum diffusion length of Si under conditions in planetary and satellite cores is less than ∼1.2 km. Additionally, the estimated strain of plastic deformation in the Earth's inner core, caused by the Harper–Dorn creep, reaches more than 103 at a stress level of 103–104 Pa, although the inner core might be slightly deformed by other mechanisms. The chemical heterogeneity of the inner core can be reduced only via plastic deformation by the Harper–Dorn creep.

scholarly journals Phase Equilibrium and Interdiffusion in Poly(Vinyl Methyl Ether)-Water System

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2445 ◽  
Author(s):  
Uliana V. Nikulova ◽  
Anatoly E. Chalykh
Keyword(s):  
Phase Equilibrium ◽  
Methyl Ether ◽  
Diffusion Coefficients ◽  
Water System ◽  
State Diagram ◽  
Pair Interaction ◽  
Dilute Solution ◽  
Vinyl Methyl ◽  
Vinyl Methyl Ether ◽  
Kinetics Of

The phase state diagram of the poly(vinyl methyl ether)-water system in a wide concentration range was obtained by the optical interferometry method. It was shown that this system was characterized by a complicated phase equilibrium with two lower critical solution temperatures, one of which was located in the concentrated region at 21 °C, and the other one in the region of a dilute solution at 31 °C. In the framework of the Flory–Huggins theory, pair interaction parameters were calculated for different parts of the binodal curves, and an attempt was made to reverse simulate the diagram in different conditions. It was suggested that the unusual character of the diagram was associated with the formation of a complicated complex between PVME and water in the middle region of the compositions. Concentration profiles for different temperatures were constructed. For the first time for this system, the numerical values of the diffusion coefficients of poly(vinyl methyl ether) (PVME) into water and water in PVME were obtained. Concentration and temperature dependences of diffusion coefficients were constructed and analyzed. The kinetics of water sorption in PVME was plotted, the clustering integral was calculated, and the approximate number of molecules in a water cluster was estimated. It was shown that in the dilute solution region upon passing through the binodal curve, the interphase disappeared immediately, and the remaining fluctuation of the concentration decreased in size with time. The kinetics of this process was estimated from the change in the size of such a particle.

Loop patch orientations in the matrix structure of cyclically deformed copper

1988 ◽  
Vol 101 ◽  
pp. 75-85 ◽  
Author(s):  
J.I. Dickson ◽  
Hong Bande ◽  
G. L'Espérance
Keyword(s):  
Matrix Structure ◽  
The Matrix

Phase State Diagrams of a Four-Component System Al-Si-N-O - Analysis of the Thermodynamic Stability of Sialon Compounds Dased on Energy Crystal-Chemistry

2020 ◽  
Vol 303 ◽  
pp. 97-103
Author(s):  
V.A. Vlasov ◽  
Anatoliy A. Klopotov ◽  
V.I. Vereshchagin ◽  
O.G. Volokitin ◽  
K.A. Bezukhov ◽  
...  
Keyword(s):  
Crystal Chemistry ◽  
Crystalline Structure ◽  
Thermodynamic Stability ◽  
Phase State ◽  
State Diagram ◽  
The State ◽  
Component System ◽  
State Diagrams ◽  
Pearson Symbol

The paper presents the results of the analysis of the state diagram of compounds in the system А12O3-SiO2. It has been found that the presence and the concentration of oxygen have a very important effect on formation of compounds with a crystalline structure in different syngony based on SIALON. Oxygen contributes to transition of the metastable AlXSi3-XN4compound into stable one. The parameter of structural “friability” of compounds has been used in the analysis of thethermodynamic stability of compounds in the Al-Si-N-O system. It has been foundthat the SiAl4O2N4 compound with the 12H-SIALON structure (Pearson symbol hP32) has the greatest thermodynamic stability among the compounds under study in this system.

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