Co-continuous polymer blends

Miles IS, ZurekA (1988) Preparation, structure, and properties of two-phase co-continuous polymer blends. Poly Eng Sci 28 796... 

Specific Interactions Induced Controlled Dispersion of Multi wall Carbon Nanotubes in Co-Continuous Polymer Blends... 

Co-continuous polymer blends of 50/50 polyamide6/acrylonitrile-butadiene-styrene copolymer (PA6/ABS) involving multiwall carbon nanotubes (MWNTs) were prepared by melt mixing technique in order to develop conducting composites utilizing the concept of double-percolation. To control the dispersion and to selectively restrict MWNTs in the PA6 phase of the blends, MWNTs were pre-treated with two modifiers which differ in their molecular length scales and... 

Nanocomposites consist of a nanometer-scale phase in combination with another phase. While this section focuses on polymer nanocomposites, it is worth noting that other important materials can also be classed as nanocomposites—super-alloy turbine blades, for instance, and many sandwich structures in microelectronics. Dimensionality is one of the most basic classifications of a (nano)composite (Fig. 6.1). A nanoparticle-reinforced system exemplifies a zero-dimensional nanocomposite, while macroscopic particles produce a traditional filled polymer. Nanoflbers or nanowhiskers in a matrix constitute a one-dimensional nanocomposite, while large fibers give us the usual fiber composites. The two-dimensional case is based on individual layers of nanoscopic thickness embedded in a matrix, with larger layers giving rise to conventional flake-filled composites. Finally, an interpenetrating network is an example of a three-dimensional nanocomposite, while co-continuous polymer blends serve as an example of a macroscale counterpart. 

Willemse et al. (1999) studied the influence of interfacial tension on the composition range within which fully co-continuous polymer blend structures can exist for different blends with selected matrix viscosities and viscosity ratios. The critical composition for full co-continuity was found to increase with increasing interfacial tension, narrowing the composition range. The effect of the interfacial tension on the critical composition was found to be composed of two counteracting effects the stability of the co-continuous morphology and the phase dimensions. The latter effect was smaller than the former. 

Historically, any material containing two or more polymers, each in network form, without induced cross-links between the individual polymers, usually produced by polymerizing and/or cross-linking at least one component in the immediate presence of the other, thus thermoset in character. Currently, the term IPN encompasses the thermoplastic co-continuous polymer blends, as well as ionomers and block and graft... 

G.H. Fredrickson, F.S. Bates, Stabilizing co-continuous polymer blend morphologies with ABC block copolymers, European Physical Journal B 1 (1) (1998) 71-76. 

The concept of co-continuous polymer blends with carbon black preferentially located in one of the continuous polymer phases or at the polymer-blend interface has been studied for more than a decade with an aim to reduce the percolation threshold. Examples of this kind are the work by Geuskens et al. in as early as 1987 [31], which shows that for the same carbon loading, the resistivity of the co-continuous polymer/rubber blends is several orders of magnitude smaller than that of the single polymer/carbon black composites. Recent works on polymer/elastomer combinations [32,33] and on polymer/polymer systems [34- 1] have also shown that the... 

Guarino, V., Guaccio, A., Ambrosio, L. Anipulating co-continuous polymer blends to create PCL scaffolds with fully interconnected and anisotropic pore architecture. J. Appl. Biomater. Biomech. 9(1), 34 (2011)... 

Li J, Ma PL, Favis BD. The role of the blend interface type on morphology in co-continuous polymer blends. Macromolecules 2002 35(6) 2005-16. 

Riscanu D, Favis BD, Feng C, Matsuura T. Thin-film membranes derived from co-continuous polymer blends preparation and performance. Polymer 2004 45 5597-609. 

Immiscible polymer blends, Izod impact, Co-continuous polymer blends... 

The use of styrenic block polymers to provide a topological template in producing co-continuous (IPN) blends of thermoplastics. ... 

In a sense, the styrene-butadiene block copolymers, SB or SBS, (first reported in 1956) constituted the next stage of PS modification. The triblock styrene-diene thermoplastic elastomers were patented in 1962, and soon incorporated in blends with PS, PP, LDPE, HDPE, PPE, PET, PBT, or PC, either as impact modifiers or compatibilizers [Bull and Holden, 1977]. In the 1977-78 patents (applications in 1976) it was disclosed that selective hydrogenation of these copolymers leads to new materials, with properties particularly attractive for polymer blends. For example, blending hydrogenated-SBS, or SEES, generated phase co-continuity in blends with PP, PA, PC, PBT, PES, etc. [Gergen et al., 1987]. More recent modification of these copolymers involved incorporation of acidic or acid-anhydride moieties. 

Eeonomers are a new class of conductive additives for thermoplastics made via in-situ deposition of intrinsically conductive polyaniline or polypyrrole on carbon black. Eeonomers are highly thermally stable, pH neutral conductive materials that are compatible with the chemistry and melt processing conditions of acid sensitive polymers. Compounding studies with thermoplastics indicate better electrical, mechanical, and melt flow properties of Eeonomer blends as compared to blends with traditional carbon blacks. In co-continuous plastic blends it was possible to fine tune the polarity of Eeonomer by varying the conductive polymer to CB ratio. The same variation affords very low percolation thresholds due to preferred Eeonomer localization at the 2D phase boundary. 

Marin N, Favis BD (2002) Co-continuous morphology development in partially miscible PMMA/PC blends. Polymer 43 4723 1731... 

Potschke P, Paul DR (2003) Formation of co-continuous structures in melt-mixed immiscible polymer blends. J Macromol Sci Polym Rev C43 87-141... 

Willemse RC (1999) Co-continuous morphologies in polymer blends stability. Polymer 40 2175-2178... 

Tol RT, Groeninckx G, Vinckier I, Moldenaers P, Mewis J (2004) Phase morphology and stability of co-continuous (PPE/PS)/PA6 and PS/PA6 blends effect of rheology and reactive compatibilization. Polymer 45 2587-2601... 

Immiscibility of polymers in the melt is a common phenomenon, typically leading to a two-phase random morphology. If the phase separation occurs by a spinodal decomposition process, it is possible to control the kinetics in a manner that leads to multiphase polymeric materials with a variety of co-continuous structures. Common morphologies of polymer blends include droplet, fiber, lamellar (layered) and co-continuous microstructures. The distinguishing feature of co-continuous morphologies is the mutual interpenetration of the two phases and an image analysis technique using TEM has been described for co-continuous evaluation.25... 

Pernot H et al. (2002) Design and properties of co-continuous nanostructured polymers by reactive blending. Nat Mat 1 54... 

The sales of plastics continue to increase in a large part due to technical and economic advancements of polymer blends. Reactive blending is a useful technique for elastomers but, it appears that chemistry could also play an important role in the correct microstructure adjustment of thermoplastic alloys. Interfacial reactivity should be the focal point in maintaining the expected structure during subsequent stages of manufacture. Besides industrial examples, various kinds of polymeric co-reacting systems are also presented in order to emphasise the key factors of reactive blending. 

REDOR was also applied to examine the structure and dynamics of interfaces of heterogeneous polymer blends. A heterogeneous blend was prepared from [carbonyl- C]polycarbonate and poly(p-fluorostyren-co-styrene) copolymer of p-fluorostylene. The blend was formed by coprecipitation from chloroform into methanol. A fluorine dephased REDOR signal indicates that the 1 polycarbonate chain in 20 exists at the interface, suggesting that the polycarbonate phase is embedded in a continuous polystyrene matrix which is 200 A thick or 400 A in diameter [54],... 

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