Alloys, polymeric

POLYMERIC ALLOYS MODEL MATERIALS FOR THE UNDERSTANDING OF THE STATISTICAL THERMODYNAMICS OF MIXTURES... 

In solution, block copolymers display interesting colloidal and interfacial properties. They can be used as emulsifying agents in water-oil and oil-oil systems (6 ). In the later case, the oil phases are solid and they give rise to polymeric alloys (7.) or they are liquid and they allow the preparation of latexes in organic medium (8 ). However, the molecular structure of block copolymers based on polybutadiene PB (70 ) and polystyrene PS behave as thermoplastic elastomers when engaged in multiblock (PB-PS)n or triblock (PS-PB-PS) structures but never when implied in inverse triblock or diblock arrangements. Similarly the... 

Class A is subdivided into two subclasses the intramolecular blends or copolymers (Al) and the intermodular blends (A2) or Polymeric Alloys. Both subclasses can be subdivided again on the basis of homogeneity or heterogeneity. 

Cabasso L, Jagur-Grodzinski L, and Vofsi D. A study of permeation of organic solvents through polymeric membranes based on polymeric alloys of polyphosphonate and acetyl cellulose. II. Separation of benzene. J Appl Polym Sci 1974 18 2137-2145. 

Estaloc. [BFGoodrich BFGoodrich UK] Mixture of thermoplastic polyurethane, reinforcement, polymeric alloys, ad(ti-tives reinforced engineeriitg thermoplastic. 

For useful polyblends, the term compatibilization refers to the absence of separation or stratification of the components of the polymeric alloy during the expected useful lifetime of the product. Optical clarity of a polyblend is related to the particle size of the dispersed phase and/or the difference in the... 

POM-b-PC with PES, PEEK, PA or PAN fihn-forming thermoplastic polymeric alloys Dheineta/., 1993... 

Polymer alloys often exhibit microphase separation. The heterogeneous morphologies are determined not only by the composition of the system but by the processing conditions as well. The microstructure influences the properties of polymeric alloys [40]. For example, the addition of a second phase of dispersed rubbery particles into the polymer matrix results in a great enhancement of toughness [41]. 

Because of their unique properties, block copolymers are increasingly used commercially, either as materials themselves or as additives in polymeric alloys. The most developed systems have been copolymers composed of two or three monomer units with two or three blocks. In the solid state, block copolymers are phase-separated, and hence they can be considered as solid emulsions. The different types of structure of the materials and the resulting properties depend on both the structure and the composition of copolymer, as exemplified in the case of biblock (SB) and triblock (SBS) copolymers of styrene and butadiene, illustrated in Figure 4.3. 

This is not the case for copolymers containing a majority of styrene units (high-impact polystyrene) and for terpolymers composed of acrylonitrile, butadiene and styrene (ABS), which are used widely as shock absorbers. The latter is a cohesive polymeric alloy stabilised by distribution of the different chains between phases. 

Major Applications Indicator,4-6 polymeric alloys, toothpaste and mouthwash, disinfectant, cosmetics, paints o Safety/Toxicity No data available... 

Detailed analytical and numerical studies of the above questions are in progress, and a very rich and nonadditive dependence of the phase behavior on the precise nature of the attractive potentials, single chain architecture, and thermodynamic state is found [67, 72]. A full understanding of these issues would provide a scientific basis for the rational molecular design of polymeric alloys. The influence of asymmetries on the spinodal phase boundary of simple model polymer alloys using analytic PRISM theory with molecular closures has been derived by Schweizer [67]. In this section a few of these results are briefly discussed. 

M. Shen and H. Kawai, Properties and Structure of Polymeric Alloys, AIChE J. 24(1), 1 (1978). Review of block copolymers and IPNs. Gradient IPNs. Thermodynamics of mixing. 

Noolandi, J. (1984) Recent advances in the theory of polymeric alloys, Polym. Eng. 

The new materials combined by two or more kinds of polymers in some way are customarily called polymer blends, or polymeric alloys, and have structures and properties different from those of the original component. The composite materials composed of polymer and inorganic materials are called polymer matrix composites. Inorganic materials, especially inorganic fillers such as calcium carbonate, talcum powder, and mica powder, which use inorganic minerals as raw materials, are widely used because of their low cost and convenient filling. 

Suitable for plast. PVC, PU, TPU, TPE, polymeric alloys, silicones, nylon. 

Foamable polymeric alloy United States 4,207,402 1980 Monsanto... 

This situation creates many difficulties in estimating the composition and ratio of separated phases. At equilibrium conditions, it is sufficient to know the phase diagram to obtain these values. In real conditions of producing polymeric alloys, it can not be done, due to the non-equilibrium conditions of a phase sepa-... 

Particular applications which come to mind are cntical applications of potymers to the manufacture of electronic components and the design of polymeric alloys for aircraft fuselage assembly w+iich retain their properties for many years over which the alloy must retain the physical properties at high or low operating temperatures. 

The polymeric alloys described in section 4.3.1 were principally investigated for use in waveguide applications, and so, to avoid optical losses, concentrations that did not give crystalline precipitates in the polymer were used. Through-plane optics can, however, tolerate poorer optical quality samples, and so microcrystalline polymer samples have been investigated for these applications. 

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