Phase separation in blends of linear polymers formed in situ
 according to different mechanisms

This article is devoted to the analysis of the results of the investigation of the process of forming mixtures of linear polymers formed simultaneously in situ according to different mechanisms. The first mechanism is polyaddition, the second mechanism is radical polymerization. This is one of the possible ways to obtain multicomponent polymer systems. The kinetics of chemical reactions of the formation of components and the phase separation which accompanies these reactions were studied for mixtures of poly(methyl methacrylate) (PMMA) with two polyurethanes (PU) of different chemical nature of both flexible and rigid blocks. PU-1 was synthesized from macrodiisocyanate based on oligo(tetramethylene glycol) with molecular mass 1000 g·mol–1 and hexamethylene diisocyanate taken in the molar ratio 1 : 2 using diethylene glycol as a chain extender. PU-2 was synthesized from macrodiisocyanate based on olygo(propylene glycol) with molecular mass 1000 g·mol–1 and toluylene diisocyanate taken in the molar ratio 1 : 2 using butanediol as a chain extender. The mixture of polystyrene (PS) with PU-2 was studied too. It is established that regardless of the chemical nature of the components, the process of in situ mixture formation is subject to general laws. In particular, the change in the chemical nature of the component formed by the mechanism of polyaddition (mixtures PMMA/PU-1 and PMMA/PU-2) or of the component formed by radical polymerization (mixtures PMMA/PU-2 and PS/PU-2) does not affect the nature of the dependence of the conversion degree of components and the fraction of formed polymers at the beginning of the phase separation on the composition of the initial reaction mixtures. Only the absolute values of these parameters change due to different reactivity and different thermodynamic compatibility of the mixed components.

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In situ microscopic studies on the structures and phase behaviors of SF/PEG films using solid-state NMR and Raman imaging

Physical Chemistry Chemical Physics ◽

10.1039/c6cp03314h ◽

2016 ◽

Vol 18 (24) ◽

pp. 16353-16360 ◽

Cited By ~ 7

Author(s):

Congheng Chen ◽

Ting Yao ◽

Sidong Tu ◽

Weijie Xu ◽

Yi Han ◽

...

Keyword(s):

Phase Separation ◽

Solid State Nmr ◽

Random Coil ◽

Rich Domain ◽

Microscopic Studies ◽

Helix Conformation ◽

Phase Behaviors ◽

Protein Rich ◽

Β Sheet

SF was incompatible with PEG in some extent, and the phase separation took place in their blend film. The conformation of SF in the interface between SF and PEG was changed to the β-sheet, while that in the protein-rich domain remained in the random coil and/or helix conformation.

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Rubber-modified epoxies: In situ detection of the phase separation by differential scanning calorimetry

Polymer ◽

10.1016/0032-3861(93)90528-i ◽

1993 ◽

Vol 34 (18) ◽

pp. 3960-3961 ◽

Cited By ~ 6

Author(s):

Dong Pu Fang ◽

C.C. Riccardi ◽

R.J.J. Williams

Keyword(s):

Differential Scanning Calorimetry ◽

Phase Separation ◽

Scanning Calorimetry ◽

In Situ Detection

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Structure of Microphase-Separated Silica/Siloxane Molecular Composites

MRS Proceedings ◽

10.1557/proc-171-57 ◽

1989 ◽

Vol 171 ◽

Cited By ~ 8

Author(s):

Dale W. Schaefer ◽

James E. Mark ◽

David Mccarthy ◽

Li Jian ◽

C. -C. Sun ◽

...

Keyword(s):

Phase Separation ◽

Kinetic Studies ◽

Organic Content ◽

Small Particles ◽

X Ray ◽

Filled Elastomers ◽

Polymeric Networks ◽

Large Particles ◽

Molecular Composites

ABSTRACTThe structure of several classes of silica/siloxane molecular composites is investigated using small-angle x-ray and neutron scattering. These filled elastomers can be prepared through different synthethic protocols leading to a range of fillers including particulates with both rough and smooth surfaces, particulates with dispersed interfaces, and polymeric networks. We also find examples of bicontinuous filler phases that we attribute to phase separation via spinodal decomposition. In-situ kinetic studies of particulate fillers show that the precipitate does not develop by conventional nucleation-and-growth. We see no evidence of growth by ripening whereby large particles grow by consumption of small particles. Rather, there appears to be a limiting size set by the elastomer network itself. Phase separation develops by continuous nucleation of particles and subsequent growth to the limiting size. We also briefly report studies of polymer-toughened glasses. In this case, we find no obvious correlation between organic content and structure.

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