Compatibilization chemistry

Blends that contain no nylon can also be prepared by reactive compatibilization. However, interest in these systems has been limited somewhat by lack of control of the reaction pathways. Eor polyester-based systems, epoxide functionaHty appears to be an effective chemistry, involving reaction of the polyester chain ends (183,184). 

The use of copolymers as surfactants is widespread in macromolecular chemistry in order to compatibilize immiscible blends. These additives are sometimes named surfactants , interfacial agents or more usually compatibi-lizers . Their effect on improving different properties is observed interfacial tension and domain size decrease, while there is an increase in adhesion between the two phases and a post-mixing morphology stabilization (coalescence prevention). The aim of the addition of such copolymers is to obtain thermodynamically stable blends, but the influence of kinetic parameters has to be kept in mind as long as they have to be mastered to reach the equilibrium. Introducing a copolymer can be achieved either by addition of a pre-synthesized copolymer or by in-situ surfactant synthesis via a fitted re-... 

In spite of the large number of grafted and side functionalized polysilox-anes commercially available and the variety of modification techniques available [25,50] (hydrosilylation, thiol-ene chemistry, halogen substitution, polycondensation), only a few of them have been used as in situ-formed graft copolymer compatibilizers. 

Styrene-containing block copolymers are commercially very important materials. Over a billion pounds of these resins are produced annually. They have found many uses, including reinforcement of plastics and asphalt, adhesives, and compatibilizers for polymer blends, and they are directly fabricated into articles. Most styrene-containing block copolymers are manufactured using anionic polymerization chemistry. However, anionic polymerization is one of the more costly polymerization chemistries because of the stringent requirements for monomer and solvent purity. It would be preferred, from an economic cost perspective, to have the capability to utilize free radical chemistry to make block polymers because it is the lowest cost mode of polymerization. The main reasons for the low cost of FR chemistry are that minimal monomer purification is required and it can be carried out in continuous bulk polymerization processes. 

Fig. 2 Reactions at the hydroxyl groups of glycosyl residues of oligo-/polysaccharides. (A) Basic a(l 4) linked glycosyl residue. (B) Oxidation at C6 position to form uronic acid. (C) Oxidation/substitution at C2 position to form acetate. (D) Oxidation/ substitution at C2 position to form glucosyl-2-amine. (E) Oxidation/substitution/compatibilization at C2 position to form glucosyl-2-A-acetyl. (F) Oxidation/substitution/compatibilization at C4 position compatibilization glycosyl-4-sulfate. (G) Oxidation/activation at C6 position compatibilization glucosyl-6-phosphate. (Molecular modeling SWEET, http //www.dkfz-heidelberg.de/spec/sweet2/doc/index.php. Chemistry MDL ISIS/draw.) (View this art in color at www.dekker.com.)...

CZVIKOVSZKY T., Radiation-assisted compatibilization of polymers, IAEA Consultants Meeting Advances in radiation chemistry of polymers, Univ. Notre Dame, Indiana, USA, 13-17 Sept. 2003. 

Advancements in synthetic polymer chemistry have allowed a remarkable range of new nonlinear block copolymer architectures to be synthesized. The result is a wide variety of new materials with the capacity to form self-assembled phases in bulk and in solution. At present our synthetic capabilities exceed our understanding, both theoretical and experimental, of the properties of such macro-molecular systems. We anticipate that a better understanding of structure-property relationships for these materials will lead to impressive new polymers with applications such as structural plastics, elastomers, membranes, controlled release agents, compatibilizers, and surface active agents. From the synthetic standpoint it seems likely that recent advances in living free radical polymerization will make the syntheses of many non-linear block copolymers more commercially appealing. 

It is to be hoped that fumre work on Reactive Compatibilization will combine the excellent materials science that has been done to date with additional considerations of the chemical processes occurring. Such knowledge of the chemistry, coupled to fluid mechanics and morphology development models, would provide a powerful tool for optimization of known and invention of new Reactive Compatibilization processes to prepare commercially valuable polymer blends. 

Reactive processing combines fine polymer chemistry with polymer processing. Thus, development of the reactive compatibilization process involves ... 

Dispersion aids and compatibiUzers based on reactive phosphato-titanate chemistries are also said to reduce viscosity of fiUed compounds. They are compatible with nonpolar polymers such as POs, and are available in masterbatch form (more is said about these compatibilizers in Chapter 14) [11-1]. 

Czvikovszky, T., Hargitai, H., Compatibilization of recycled polymers through radiation treatment. Radiation Physics and Chemistry 1999,55(5-6), 727-730. 

Liu, B., Jiang, L., Liu, H. and Zhang, J. (2010) Synergetic effect of dual compatibilizers on in situ formed poly(lactic acid)/ soy protein composites. Industrial and Engineering Chemistry Research, 49, 6399-6406. 

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