Blends dynamics

Interfacial adhesion and, thereby, compatibility can be enhanced by the selective crosslinking reaction in polymer blends. Inoue and Suzuki [26] reported the properties of blends dynamically crosslinked PP-EPDM blends. The crosslinking agent was yV,N -/w-phenylene-bismaleimide - poly(2,2,4 - trimethyl - 1,2-dihydroquino -line) system. Increase in interfacial adhesion leads to... 

Gessler patent on PP-CllR blends, dynamically cured... 

Dynamic vulcanizate Blend, dynamic vulcanizate Blend... 

Recently, a new concept in the preparation of TPVs has been introduced, based on the reaction-induced phase separation (RIPS) of miscible blends of a semicrystalline thermoplastic in combination with an elastomer, with the potential for obtaining submicrometer rubber dispersions. This RIPS can be applied to a variety of miscible blends, in which the elastomer precursor phase was selectively crosslinked to induce phase separation. Plausible schematic representation of the morphological evolution of dynamic vulcanization of immiscible and miscible blends is shown in Fig. 9. For immiscible blends, dynamic vulcanization leads to a decrease in the size... 

Detection of miscibility Miscible blends dynamic shear relaxation spectra linear viscoelasticity Utracki Schlund, 1987... 

Dynamically vulcanized blends Dynamically vulcanized blends are produced by melt mixing an elastomer phase with a thermoplastic (the elastomer being the major component) and then curing the elastomer during melt mixing. The resulting blend comprises the thermoplastic resin filled with high concentration of rubber particles well bonded to the matrix. Examples include EPDM/PP (Santo-... 

A. Y. Coran, Thermoplastic elastomers based on elastomer-thermoplastic blends dynamically vulcanized, in Thermoplastic Elastomers—A Comprehensive Review, N. R. Legge, G. Holden, and H. E. Schroeder (eds.), Hanser Publishers, Munich, 1987. 

Concentration fluctuations are prevalent at some compositions of polymer blends, resulting in spatial heterogeneity and broadening of the frequency dispersion of the segmental a-relaxation in polymer blends (Shears and Williams, 1973 Zetsche et al., 1990). This factor was the center of attention in models by blend dynamics by Zetsche and Fischer (1994) and Katana et al. 

Pathak, J. A., S. K. Kumar, and R. H. Colby. 2004. Miscible polymer blend dynamics Double reptation predictions of linear viscoelasticity in model blends of polyisoprene and polyjvinyl ethylene). Macromolecules 37 6994—7000. 

Generally, reactive extrusion deals with high melt-viscosity systems and diffusion-based reactions. Moreover, chemical reactions also frequently entail a morphology development (e.g., reactive blending, dynamic vulcanization) that progresses along the screw at a rate that depends on local temperatures, residence time, stress levels, and... 

Naturally, a theory of polymer-blend dynamics is less desirable if it is constructed just for explaining the local segmental dynamics of polymer blends, but has no utility for the consideration of problems related to local segmental dynamics in homopolymers. Some examples of challenging problems regarding homopolymers will be discussed in Sections 2.5 and 2.6. 

A key assumption of DO is that, although there are two components, there is only one network stress. The contribution of each component to this stress should however be determined from some mixing rule which relates blend dynamics to that of the pure components. 

The TPE polyolefin copolymers and blends (including stereo-copolymers [7]), as well as the reactive rubber-plastic blends, dynamically vulcanized TPEs, and melt-processible rubbers are beyond the scope of this chapter. 

Miscible Blend Dynamics and Length Scales of Mixing... 

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