Blends and Alloys

Alloys are combinations of polymers that are mechanically blended. They do not depend on chemical bonds, but do often require special compatibilizers. Plastic alloys are usually designed to retain the best characteristics of each constituent. Most often, property improvements are in such areas 

The classic objective of alloying and blending is to find two or more polymers whose mixture will have synergistic property improvements (Fig. 6-8). Among the techniques used to combine dissimilar polymers are cross-linking to form what are called interpenetrating networks (IPNs), and grafting, to improve the compatibility of the plastics. 

Alloys can be classified as either homogeneous or heterogeneous. The former can be depicted as a solution with a single phase or single glass-transition temperature (7 ). A heterogeneous alloy has both continuous 

Plastic Cost index Yield strength index Impact strength index 

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L. A. Utracki, Polymer Alloys and Blends, Thermodynamics and RJjeology, Hanser PubUshers, New York, 1989, p. 124, and references cited therein. 

Alloys and blends are of great commercial significance. The archetype of "alloys" is the poly(phenylene oxide)—polystyrene resin discussed eadier. Important examples of blends based on immiscible resins are afforded by the polycarbonate—poly(butylene terephthalate) resins and polycarbonate—ABS blends. 

Companies produce alloys and blends in order to extend their existing resin capacity and product lines without high capital investment and to achieve property profiles required for specific appHcations. 

Use of polymer alloys and blends as matrices for composites, reinforcements, and foams. 

TPs come in greater variety than TSs. They also tend to be more readily to specialty compounding as copolymers, multipolymers, alloys and blends, often customized for cost-effective adaptation to specific application requirements. Unlike TSs, they are in most cases reprocessable without serious losses of properties. 

Utracki, L.A. Polymer Alloys and Blends Thermodynamics and Rheology. (1990)Hanser Publishers, New York. 

Other models are based upon the immiscibility of polymer blends described above, and they model the system as Newtonian drops of the dispersed polymer with concentration (pi in a Newtonian medium of the second polymer with concentration (p2 = — (pi. There exists some concentration, cpu = cp2i — 1, at which phase inversion takes place that is, at snfficiently high concentration, the droplet phase suddenly becomes continuous, and the second phase forms droplets. The phase inversion concentration has been shown to correlate with the viscosity ratio, A. = r i/r 2, and the intrinsic viscosity for at least a dozen polymer alloys and blends ... 

Utracki LA (1990) Polymer alloys and blends. Hanser, Munich, New York, p 1... 

L.A. Utracki, History of commercial polymer alloys and blends (from a perspective of the patent literature), Polymer Engineering Science, 35(1) 2-17, January 1995. 

Khandpur AK et al. (1995) Compatibilizers for A/B blends A-C-B triblock versus A-B diblock copolymers. Polyblends 95, SPE Regional Technical Conference on Polymer Alloys and Blends. Boucherville, Quebec, Oct 19-20, pp 88-96... 

Utracki, L. A. In Industrial Polymer Alloys and Blends Hanser Ver. Muchen, 1989. 

The use of ceramic and polymeric constituents in special alloys and blends has become widespread in recent years. These "polymeric cements have been applied to a variety of uses from pavement repair and maintenance (17) to artificial teeth (18,19,20) and endosseous implantTT (21)... 

Hydrogen bonding is a subject of remarkable diversity as it is present in and dictates the behavior of an enormous number of systems including aqueous solutions, systems of biological/biomedical interest, pharmaceuticals, colloids and surfactants, physical networks and gels, adhesives and pastes, extractives and binders, polymer alloys and blends. There are many reviews of the subject in the... 

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