Polymer blends phase separation

Network Structure of Micrometre-Scale Cavity Obtained from Phase-Separated Polymer Blends as Characterised by Using... 

NETWORK STRUCTURE OF MICROMETRE-SCALE CAVITY OBTAINED FROM PHASE-SEPARATED POLYMER BLENDS AS CHARACTERISED BY USING PROBE MOLECULES... 

Figures la and Ic show the structure of the phase-separated polymer blend films obtained by dip coating from a PS-COOH/PMMA (30 70 weight ratio) solution. The morphology of the as-deposited films of two different (15 and 30 nm) thicknesses agreed well with their PS content of 30%. Indeed, the minor PS phase was dispersed in the major PMMA phase. However, after the anneahng and extraction of PMMA, the grafted PS layer demonstrated a rather different type of surface structures for the PS-COOH /PMMA films of different...

Wang, H., Composto, R.J. Kinetics of surface and interfacial fluctuations in phase separating polymer blend films. Macromolecules 35(7), 2799-2809 (2002)... 

Nisato, G., Etmi, B.D., Douglas, J.F., Karim, A. Excitation of surface deformation modes of a phase-separating polymer blend on a patterned substrate. Macromolecules 32(7), 2356-2364 (1999)... 

Lee, B. R, Douglas, J. F., and Glolzer, S. C. FiUer-induced composition waves in phase-separating polymer blends. PhysRevE., 60,5812-22 (1999). 

The phase behavior and morphology of phase-separated polymer blends play a vital role in the design of membrane transport properties (Robeson 2010). Numerous applications of polymeric membranes involving gas and liquids are known. Although different transport models have been utilized successfully to relate morphology with transport properties, there is enough room for improvements as membrane applications continue to grow in such areas as gas separation. 

Bar, G Thomann, Y Brandsch, R. Cantow, H.-J. Whangbo, M.-H. Factors affecting the height and phase images in tapping mode atomic force microscopy. Study of phase-separated polymer blends of poly(ethene-co-styrene) and poly(2,6-dimethyl-l,4-phenylene oxide). Langmuir 1997,13,... 

Phase-separated polymer blends often feature nanoscale phase dimensions ... 

Importance of mutual diffusion Phase separation, polymer blend processing Relation to interaction parameter Transient diffusion Pick s law of diffusion Damped wave diffusion and relaxation Semi-infinite medium, finite slab Periodic boundary condition... 

Chopra Divya, Vlassopoulos Dimitris, and Hatzikiriakos Savvas. Nonlinear rheological response of phase separating polymer blends Poly(styrene-co-maleic anhydride)/ poly(methyl methacrylate). J. Rheol. 44 no. 1 (2000) 27-45. 

Phase separation (polymer blends, copolymers, polymer alloys)... 

The types of polymer blends are quite varied and comprise many diverse combinations of polymeric materials of both academic and industrial interest. The primary differentiation of polymer blends involves their phase behavior specifically, miscibility versus phase separation. Miscibility is related to mixing approaching the molecular dimension scale such that the properties observed are that expected of single phase materials. Miscibility does not imply ideal mixing at the molecular scale. Miscibility was initially believed to be an extremely rare observation and, in fact, most random combinations of binary blends are indeed phase separated. However, many miscible combinations have been noted and the rationale for miscibility is well-established. The primary advantage of miscible versus phase separated polymer blends is the blend property profile, which is generally intermediate between that of the... 

This book is divided into specific subject areas of importance to polymer blend technology starting in Chapter 2 with the fundamentals. In this chapter, the thermodynamic relationships relevant to polymer blends are detailed along with discussions on the phase behavior and phase separation processes. Specific interactions in polymer blends leading to miscibility or improved mechanical compatibility are also discussed. The mean field theory and the association model are presented. The importance of the interfadal characteristics of phase separated polymer blends is also covered in Chapter 2. In Chapter 3, compatibiUzation methods for achieving compatibihty of phase separated blends are discussed, including the methods noted in Table 1.2. 

Figure 2.17 Generalized concentration profile across the interface of a phase separated polymer blend as a function of the interaction parameter...

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