Miscible polymer

Mixtures of polymers at surfaces provide the interesting possibility of exploring polymer miscibility in two dimensions. Baglioni and co-workers [17] have shown that polymers having the same orientation at the interface are compatible while those having different orientations are not. Some polymers have their hydrophobic portions parallel to the surface, while others have a perpendicular disposition. The surface orientation effect is also present in mixtures of poly(methyl methacrylate), PMMA, and fatty acids. 

The Flory-Huggins Interaction Parameter. These ideas, based on a study of polymer miscibility, have been appHed to plasticizers according to the foUowiag equation ia which is the molar volume of the plasticizer, obtaiaed from molar mass figures and density values at T, and represents the iateraction parameter (11). 

In a fundamental sense, the miscibility, adhesion, interfacial energies, and morphology developed are all thermodynamically interrelated in a complex way to the interaction forces between the polymers. Miscibility of a polymer blend containing two polymers depends on the mutual solubility of the polymeric components. The blend is termed compatible when the solubility parameter of the two components are close to each other and show a single-phase transition temperature. However, most polymer pairs tend to be immiscible due to differences in their viscoelastic properties, surface-tensions, and intermolecular interactions. According to the terminology, the polymer pairs are incompatible and show separate glass transitions. For many purposes, miscibility in polymer blends is neither required nor de-... 

Olabisi O, Roberson LM, Shaw MT (1979) Polymer-Polymer miscibility, Academic, New York... 

Starkweather H.W., Cocrystallization and polymer miscibility, J. Appl. Polym. Sci., 25, 139, 1980. Seguela R. and Pmd homme J., Affinity of grain deformation in mesomorphic block polymers submitted to simple elongation. Macromolecules, 21, 635, 1988. 

Polymer-Polymer Miscibility and Compatibilization of Polymer Blends.298... 

Recent work on thermoplastic vulcanizates (TPVs) will not be included in this chapter since it is being reviewed elsewhere in the book. Abbreviations for some mbbers and accelerators will be used throughout in place of their full names as shown in Table 11.1. Acronyms for other polymers and additives wUl be provided in the text as required. A short discussion of polymer miscibility and compatibUization of polymer blends will be provided for better appreciation of the subject. 

POLYMER-POLYMER MISCIBILITY AND COMPATIBILIZATION OF POLYMER BLENDS... 

Lohse et al. have summarized the results of recent work in this area [21]. The focus of the work is obtaining the interaction parameter x of the Hory-Huggins-Stavermann equation for the free energy of mixing per unit volume for a polymer blend. For two polymers to be miscible, the interaction parameter has to be very small, of the order of 0.01. The interaction density coefficient X = ( y/y)R7 , a more relevant term, is directly measured by SANS using random phase approximation study. It may be related to the square of the Hildebrand solubility parameter (d) difference which is an established criterion for polymer-polymer miscibility ... 

Polymer miscibility, enhancing, 14 476 Polymer modification, supercritical fluid impregnation in, 24 20 Polymer networks, interpenetrating, 79 834 20 327... 

Olabisi, O. Robeson, L. M. Shaw, M. T. Polymer-Polymer Miscibility, Academic Press New York, 1979. 

Morawetz et al. [105,106] were the first to use non-radiative energy transfer (NRET) fluorospectroscopy for exploring polymer-polymer miscibility. The basic principle is as follows. In a system containing two kinds of fluorescence chromophore, if the emission spectrum of one (donor D) overlaps the absorption spectrum of the other (acceptor A), a non-radiative energy transfer from the former to the latter may occur when the system is excited by irradiation that the former selectively absorbs. The efflciency of energy transfer (E) inversely proportional to Icj/Ia> where Id and la denote the emission intensities of D and A, respectively, depends on the average distance r between D and A according to the relationship ... 

Olabisi O, Robeson L, Shaw M (1977) Polymer-polymer miscibility. Academic Press, New York... 

The Flory-Huggins theory of polymer solutions has been documented elsewhere [26, 27]. The basic parameters necessary to predict polymer miscibility are the solubility parameter 6, the interaction parameter %, and the critical interaction parameter ( ) . 

Polymers are being blended in the fluid state. The first question is are the polymers miscible We can distinguish between two cases ... 

O. Olabisi, L.M. Robeson and M.T. Shaw, Polymer-Polymer Miscibility,... 

C NOE spectroscopy under MAS was used for probing polymer miscibility in polymer blends, polystyrene/polyvinyl methyl ether (PS/PVME) [42], This study takes advantage of the fact that crosspeaks appear only between spins that are neighbours of each other,... 

Bucknall, in addition to micrographic studies, confirmed polymer miscibility via dynamic mechanical testing that the Tg peaks in these systems became intermediate to the pure components indicating mutual compatibility [107-109]. This result will be discussed in the following section. 

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. 

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