Polymer Blend Miscibility

Massa, Voit, and coworkers1231 conducted a survey of the phase behavior of blends of these polyester hyperbranched polymers with linear polymers. Blend miscibility of a hydroxyl terminated polyester was comparable to that of poly(vinylphenol) indicating strong H-bonding interactions, whereas miscibility of an acetoxy terminated analog decreased relative to the hydroxy derivative. 

If there are more than two components in a mixture (as in a blend of a homopolymer with a copolymer), binary interaction parameters can be combined into a composite % parameter to describe the overall behavior of the system. For example, Choi and Jo [11] showed how the effects of copolymer sequence distribution in blends of polyethylene oxide) with poly(styrene-co-acrylic acid) can be described by an atomistic simulation approach to estimate the binary intermolecular interaction energies which are combined into a total interaction parameter for the blend. Their paper [11] also provides a list of the many preceding publications attempting to address the effects of copolymer composition, tacticity, and copolymer sequence distribution on polymer blend miscibility. In addition to the advances in computational hardware and software which have made atomistic simulations much faster and hence more accessible, work in recent years has significantly improved the accuracy of the force fields [12] used in such simulations. 

The study of polymer blend miscibility continues to attract some interest although the level of activity appears to have declined. 

Polymer blend (PB) Homologous polymer blend Miscible polymer blend... 

Table 2.4. Terms relatecJ to polymer blend miscibility (see also Chapter 1. Introduction)...

Cellulose blends with synthetic polymers also constitute an example of biodegradable polymer blends. Miscibility of cellulose with polyvinylpyrrolidone [Masson and Manley, 1991a], poly(4-vinyl pyridine) [Mason and Manley, 1991b], PAN [Nishio et al, 1987], PVAL [Nishio and Manley, 1988], and polyethyleneoxide (PEG) [Nishio et al., 1989] have been reported. Starch blends with commodity polymers have been commercialized as a low cost method to promote partial environmental degradability. While a defi-... 

The question of polymer blend miscibility derives out of the nineteenth century development of thermodynamics and studies in the same periodic of binary mixtures of low molecular weight liquids. From a thermodynamic viewpoint, Gibbs (23) formulated the stability of multiphase systems in terms of the quantity G defined by (in modem notation (24))... 

There are two main categories of polymer blends, miscible and immiscible (Figure 3.9). Miscible blends are homogeneous down to the molecular level [33]. Properties scale with the ratios of the coirstituent pol3uners [36]. 

It is generally very difficult or even impossible to predict the properties of a blend however, this is only the second step. The first problem is an understanding of the mixing properties (i.e., knowledge of under which conditions two polymers will form either a homogeneous phase or a two-phase structure) [2]. The blend miscibility is an important effect to determine the structure and properties of the new material. Polymer blend miscibility is therefore a central subject in the science and technology of polymers. 

Gamma and electron beam radiation were also used in the presence of coagents to improve polymer blend miscibility and properties. Table 9.3 summarizes all the formulations of irradiated blends containing a coagent. 

Longitudinal polymer liquid crystal + engineering polymer blends miscibility and crystallization phenomena... 

J.L. White, M. Wachowicz, Polymer blend miscibility - NMR, Chapter 7. in Annual Reports on NMR Spectroscopy, vol. 64 (Academic Press, Elsevier, London, 2008)... 

PBSA and PVPh are miscible crystalline/amorphous polymer blends. Miscibility of PBSA/PVPh blends was evidenced by the single composition-dependent glass-transition temperature over the entire blend compositions. The negative polymer-polymer interaction parameter, obtained from the melting depression of PBSA, indicates that PBSA/PVPh blends are thermodynamically miscible. 

Commercial polymer products are frequently derived from blending two or more polymers to achieve a favorable balance of physical properties. As described in Chap. 2, Thermodynamics of Polymer Blends in this handbook, from the thermodynamic point of view, there are two basic types of polymer blends miscible and immiscible. The vast majority of polymer pairs are immiscible. There are only a few commercially important polymer blends based on miscible or partially miscible (i.e., miscible within a low range of concentration) polymer pairs. It is seldom possible to mix two or more polymers and create a blend with useful properties. Instead, when preparing a new polymer blend from immiscible resins, it is necessary to devise a specific strategy for compatibilizing the mixture to provide for optimum physical performance and long-term stability. Although there do exist a very small number of commercial blends of immiscible polymers that are not compatibilized, most commercially available blends of immiscible polymers have been compatibilized by some specific mechanism. 

J. Dudowicz, K.F. Freed, J.F. Douglas, New patterns of polymer blend miscibility associated with monomer shape and size asymmetry. J. Chem. Phys. 116(22), 9983-9996 (2002b)... 

M. Rabeony, D.J. Lohse, R.T. Gamer, S.J. Han, W.W. Graessley, K.B. Migler, Effect of pressure on polymer blend miscibility a temperature-pressure supmposition. Macromolecules 31(19), 6511-6514(1998)... 

J. Sharma, Characterization of polymer blends by x-ray scattering SAXS and WAXS, in Characterization of Polymer Blends Miscibility, Morphology and Interfaces, Wiley-VCH Verlag GmbH Co. KGaA, 2015, pp. 209-236. 

There are two types of polymer blends miscible and immiscible. 

The investigation of polymer blend miscibility has been greatly enhanced in recent years by the use of small angle neutron scattering (SANS). This is a very powerful tool in examining the miscibility of blends since it can be used to directly measure the interactions between polymers. The most commonly used expression for the free energy of... 

Entropy of random copolymer can be calculated from the reactions between comonomers that were involved in the formation of the copolymer. The chain sequence distribution information can be used in estimating the entropy of the copolymer. The sequence distribution of random copolymer can be used to interpret the observations of polymer blend miscibility. The Elory-Hnggins interaction parameter can be expressed as a function of dyad and triad probabilities. 

Sometimes, in analogous to metal alloys, the term polymer alloy is used. According to the lUPAC recommendation, the term polymer alloy for a polymer blend is discouraged. The term polymer alloy should be used for polymeric materials with macroscopically uniform physical properties in their whole volume. This definition includes compatible polymer blends, miscible polymer blends, or multiphase copolymers. 

Rabeony et al 1998, Effect of pressure on polymer blend miscibility A temperature-pressure superposition. Macromolecules, Vol. 31, No. 19, PP. 6511-6514 Rodgers, 1991, Procedure for predicting lower critical solution temperature behavior in binary blends of polymers. Macromolecules, Vol. 24, No. 14, PP. 4101-4109 Rudolf Cantow, 1995, Description of phase-behavior of polymer blends by different equation-of-state theories. 2. excess volumes and influence of pressure on miscibility. Macromolecules, Vol. 28, No. 19, PP. 6595-6599... 

Semerak SN, Frank CW (1984) Excimer fluorescence as a molecular probe of polymer blend miscibility. 6. Effect of molecular-weight in blends of poly(2-vinylnaphthalene) with poly (methylmethacrylate). Macromolecules 17(6) 1148-1157. doi 10.1021/ma00136a008... 

Keywords polymer blends, miscibility, thermodynamics of mixing, homogeneous blends, heterogeneous blends. 

A second part of the study of Singh and Schweizer" described in Section V.C was to investigate the validity of a solubility parameter approach to polymer blend miscibility. Solubility parameter, or Hildebrand, theory is potentially extremely useful from a practical viewpoint... 

Characterization of Polymer Blends Miscibility, Morphology, and Interfaces, First Edition. 

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