Multiphase polymers graft copolymers

It is important to note that the Tg values of component polymers may be unaffected when they are present in multiphase blends (separate phases at the microlevel), and this is the basis for many multiviscosity oils. This is also true for block and graft copolymers, which have characteristic Tg values corresponding to the polymers of each of the comonomers. 

Needless to say, the best established architecture which can be designed by the macromonomer technique has been that of graft copolymers. With this technique we now have easy access to a variety of multiphased or microphase-separated copolymer systems. This expanded their applications into a wide area including polymer alloys, surface modification, membranes, coatings, etc. [5]. 

Copolymerization techniques offer the opportunity to control polymer structure and hence the degree of mixing of the components. The multiphase physical characteristics of polyblends are also observed in graft, block, and heterogeneous copolymers (4, 5). Materials suitable for broad temperature range viiBration damping have been prepared from polyblends (4, 6, 7), graft copolymers (2, 8), and IPN s. 

Synthesis, characterization, and chemical composition distribution investigations of graft copolymers prepared by the macromonomer technique. In Contemporary topics in polymer science, vol. 6 Multiphase macromolecular systems, ed. B. M. Culbertson. New York Plenum Press. 

Colloidal and Morphological Behavior of Block and Graft Copolymers" Molau, G. E., Ed. Plenum Press New York, 1971. "Multiphase Polymers" Cooper, S. L. Estes, G. M., Eds. ADVANCES IN CHEMISTRY SERIES No. 176, American Chemical Society Washington, D.C., 1979. 

It has been mentioned already that the initiator s solubihty in PO-monomer systems is one of the most important factors in RE technology. When grafting a monomer onto blends of olefin polymers or copolymers, the role of initiator s solubility grows since it influences the distribution factor of the initiator between individual phases in multiphase melts (1). 

Multiphase polymer blends are of major economic importance in the polymer industry. The most common examples involve the impact modification of a thermoplastic by the microdispersion of a rubber into a brittle polymer matrix. Most commercial blends consist of two polymers combined with small amounts of a third, compatibilizing polymer, typically a block or graft copolymer. 

Multiphase or multicomponent polymers can clearly be more complex structurally than single phase materials, for there is the distribution of the various phases to describe as well as their internal structure. Most polymer blends, block and graft copolymers and interpenetrating networks are multiphase systems. A major commercial set of multiphase polymer systems are the toughened, high impact or impact modified polymers. These are combinations of polymers with dispersed elastomer (rubber) particles in a continuous matrix. Most commonly the matrix is a glassy amorphous thermoplastic, but it can also be crystalline or a thermoset. The impact modified materials may be blends, block or graft copolymers or even all of these at once. 

We assumed polypeptide microdomains would be formed in the matrix from vinyl polymer chains on the electrode (Figure 1), since multiphase materials including block and graft copolymers have been known in general to form microdomain structures in the solid state (72). In fact, some of those containing polypeptide segments were found to have microdomains composed of polypeptide (72-/<. In the present case, the segments from polypeptide was considered to form hydrophilic microdomains after hydrolysis. 

As in the case of emulsion polymerization, particle morphology is ruled by the interplay between thermodynamics and kinetics. Equilibrium morphologies are reached when the internal viscosity of the polymer particle is low. Thus, due to the plasticizing effect of the alkyd resin, equilibrium morphologies are usually reached for alkyd/acrylic systems [96]. The equilibrium morphology is affected by the presence of graft copolymer that reduces the interfacial tension between the polymer phases in the particle. Methods to calculate the equilibrium morphology of multiphase polymer particles are available [43]. 

The calculation methods described above may be used for multiphase polymers such as blends, block or graft copolymers, composites, and semicrystalline polymers. 

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