Polymeric partners, thermodynamically

Block polymers and polymer blends deserve now a great intere because of their multiphase character and their related properties. The thermodynamic immiscibility of the polymeric partners gives rise indeed to a phase separation, the extent of which controls the detailed morphology of the solid and ultimately its mechanical behavior. The advent of thermoplastic elastomers and high impact resins (HIPS or ABS type) illustrates the importance of the industrial developments that this type of materials can provide. In selective solvents, and depending on molecular structure, concentration and temperature, block polymers form micelles which influence the rheological behavior and control the morphology of the material. 

The manufacture of MFCs involves blending of thermodynamically immiscible polymeric partners, differing in their melting temperatures, T.. The essential stages of MFC preparation are as follows ... 

A certain kind of radical transfer can be modelled by the transfer of a hydrogen atom from an alkane molecule to a small alkyl radical. This reaction was studied in detail in the gas phase. With hydrocarbon partners, heats of reaction are a fairly safe measure of the relative rate of transfer, as the pre-exponential Arrhenius factors remain approximately constant for a series of transfers to a given radical. Tabulated thermodynamic data indicate, however, [31, 32] that the correlation between the heat of reaction and the transfer rate is not valid for reactions of a radical with polar substrates [32, 33], In condensed phases, transfer reactions have not been sufficiently studied. Polymerizations themselves are the source of the most valuable, though incomplete, information. 

Investigations directed specifically at examining polymerizations thought to proceed via macrozwitterions, begin in the early sixties. Monomers are unpolarized and thermodynamically stable. Such monomers generate reactive ions prone to transfer and termination processes. Chains partnered by independent counterions are introduced, and the study of monomer addition to macrozwitterions is difficult if not impossible. Consequently, the work is of very uneven quality, and later investigations have shown that some of the conclusions drawn are completely erroneous. 

Radiation processing may help to overcome theoretical and technological difficulties, in the way of creating new multicomponent polymeric systems. In the present work, we focused on solving the major obstacle, the inherent thermodynamical incompatibility of partners in polymer blends, alloys, composites and recycled products. 

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