Resins single phase polymer

In addition, the polymer blends segment of the plastics industry increases at about three times faster than the whole plastics industry. Blending has been recognized as the most versatile, economic method to produce materials able to satisfy complex demands for performance. By the year 2000 the world market for polymer blends is expected to reach 51 million tons per annum, worth well over US 200 billion. The tendency is to offer blends that can be treated as any other resin on the market hence their processability must closely match that of single-phase polymer, but offer a much greater range of performance possibilities. 

Polymers in the category of engineering resins and plastics may be classified in several ways. They may be thermoplastic or thermoset. They may be crystalline or amorphous and they may be single phase or multiphase systems. This would allow for eight types of materials except that thermosets, because of their irregular cross-linked structure, are never crystalline. Single phase polymers do not have discemable second phase structures of different chemical composition. Thus homopolymers and random copolymers are single phase polymers, even if they are semicrystalline and so contain amorphous and... 

These single-phase hybrids are very different from the two-phase toughened epoxynitrile adhesives that are discussed in Chap. 8. These two-phase adhesives have redefined structural adhesives to a great extent and have opened the door to many applications that were previously not possible because of the epoxy resin s inherent rigidity. The polymer mixtures that exist as separate phases provide significant increases in toughness but have only a small improvement in elongation at typical use levels. 

The best commercial advantages of a polymer blend can be summarized by the word versatility [Olabisi et ah, 1979]. Unfortunately, miscible polymer-polymer blends usually show additivity of the component polymers properties, thus their versatility is limited. Furthermore, tike any other single-phase resin, for most apphcations miscible blends need to be toughened and/or reinforced. Thus, with the exception of PMMA/PVDF blends (primarily used for coatings) there are no miscible blends on the market The interest in miscible polymer blends is for the purpose of compatibUization and judicious selection of the processing conditions that may lead to the spinodal decomposition-type morphology (see Chapter 8 Morphology in this Handbook). 

Solution n. A single-phase mixture of two or more component, homogeneous at the molecular level, such as a resin dissolved in a liquid, that forms more or less spontaneously, will not separate, and has no fixed proportions of the components. Polymer solutions are used in the plastics industry to apply coatings, for film casting, and for spinning fibers. The term also includes gas/ gas, gas-in-liquid, liquid/liquid, and solid/ solid solutions. 

Davankov-type resins can be defined as the first kind of hypercrosslinked polymers. The single-phase hypercrosslinked polystyrene... 

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