High Performance Polymers miscible

A miscible polymer—polymer blend almost always yields a physical- property spectrum superior to the individual components, and this allows the development of a new set of products with significant savings in capital investment. Partly for this reason and partly because new and commercially viable polymers are becoming harder to come by/ the plastic industry has expended a sizeable sum towards identifying miscible high-performance polymer mixtures. Indeed, the more recent renewed experimental and theoretical programs have resulted in an increased number of known miscible blends. On the commercial scene, however, successful miscible polymer-polymer blends are still rather few and are limited to... 

Campbell JA, Goodwin AA, Mercer FW, Reddy V. Studies on a miscible polyimide blend. High Perform Polym 1997 9(3) 263-79. 

This chapter discusses blends that are based on the use of high performance polymers. Both miscible and immiscible mixtures of such polymers are discussed and advantages that are provided by both types of blends are highlighted. It is pointed out that due primarily to the molecular conformation of high performance polymers the criteria for obtaining miscible mixtures of these type of polymers are different than for more flexible type polymers... 

As has already been discussed earlier in this chapter, one of the most common ways to achieve miscibility in high temperature polymer blends is through the introduction of specific interactions between the two components in the mixture. This is not surprising, as this is also an often-used approach to develop miscibility in other types of blend systems as well. The one exception to this pattern is the case of blends of two liquid crystal polymers in which miscibility has been determined in systems in which there is no well-defined specific interaction. In those systems, miscibility appears to occur based primarily on similarities in molecular conformation between the two blend components. These results suggest that entropic effects play a significant role in defining the phase behavior of mixtures that contain high performance polymers. 

From an experimental perspective, systematic structure-property relationship studies of high performance polymer blends are needed to completely define the polymer features that lead to miscible mixtures. One of the primary focuses of those studies should be continued quantification of the molecular features, both entropic and enthalpic in nature, responsible for miscibility. Such quantitative input can, then, be used as information in theoretical developments. The entire process should be regarded as highly iterative in nature in the sense that theoretical predictions can be made, tested experimentally, and the results of the experimental work should lead to revised models that can make additional predictions. 

Arnold CA, Chen DH, Chen YP, Waldbauer RO, Rogers ME, McGrath JE (1990) Miscible blends of poly(siloxane imide) segmented copolymers and polybenzimidazole as potential high performance aerospace materials. High Perfm Polym 2(2) 83... 

The first question to be discussed is the polymer miscibility which governs the blend morphology. The solubility parameters of BMIs is 12-135 (cal cm 3)0,5 vs. 11-12 (cal cm"3)0,5 for the high-performance thermoplastics [112]. We can expect an important non-miscibility however, the morphology will also depend on some other factors (conversion at the gel point, viscosity...) and as a result different types of morphologies were identified. 

The suitability of IGC as a route to interaction thermodynamics using non-volatile stationary phases and selected probe molecules at high dilution has been noted above. Much valuable information on the miscibility of solvent-polymer systems, derived from IGC measurements, continues to be published in the literature. However, equally important is information on the state of interaction among the non-volatile components of complex polymer-containing systems. Such information is an invaluable guide to the formulation of polymer blends and fiber- and particulate-reinforced polymer compounds, and would appear to have at least equal relevance to the properties of high performance, non-... 

Poly(aryl ketones) (PEEK, PEK, and PEKK) are commercial high temperature polymers offering an excellent combination of properties combined with thermoplastic behavior. Poly(aryl ether ketone) PAEK blends have been reviewed by Harris and Robeson [1989]. Miscibility with PEI (Ultem 1000 GE) and other PI containing isopropylidene bridging units was noted. Arzak et al. [1997] reviewed the performance ofPEEK/PEI blends and noted a synergistic behavior in ductility and impact strength as reported earlier. Utility of these blends as a thermoplastic matrix candidate for advanced composites has been proposed [Harris and Robeson, 1989 Davis et al., 1992]. 

A number of technologists have attempted to obtain miscible systems with polycarbonate (PC) as one of the blend constituents. Given the high performance and cost associated with PC polymers, blends of PC and multicomponent copolymers may get the job done for less cost. PC/ABS blends have been reported in the product literature. Although they were not compatibilized, they exhibit good balance of properties. In this section a terpolymer made of three comonomers, (1) a-methlystyrene (AMS), (2) acrylonitrile (AN), and (3) methyl methacrylate (MMA) can be evaluated for miscible regions in the copolymer compositional space and blend composition with (4) tetramethyl polycarbonate (TMPC) homopolymer. The binary interaction parameter for the terpolymer/homopolymer system can be written as follows ... 

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