Polymer Blend Composites

A class of polymer blends that deserves review involves composite systems, where the polymer matrix is a polymer blend. For this discussion, composite systems will include inorganic particulates or fibers, organic fibers/fillers, carbon black and natural products. The salient feature of the filler will be the retention of the same basic shape of the filler after melt compoimding with the polymer blend. Organic fibers (such as Kevlar fibers) would be considered in this subset of polymer blends. 

There are situations where polymer blends may exhibit unique characteristics for utility in composite systems. One of these examples involves the segregation of conductive carbon black at the interface of phase separated polymer blends to yield a much lower concentration to reach the percolation threshold [ 1098,1099 ]. Another area of interest involves the addition of a polymer offering excellent adhesion to the filler as well as mechanical compatibility (or miscibility) with the matrix polymer. The polymeric interfacial agent can offer improved dispersion of this filler in addition to improved stress transfer across the interface between matrix and filler. The preferential concentration of filler particles in one phase is a situation 

ABS PC Mica SEane used to promote adhesion mica addition decreased rate of burning 1168 

PS PMMA Organoclay Organoclay concentrated in PMMA and at blend interface organoclay addition decreased domain size of the blend (com-patibEization effect) 1169 

HIPS LCP Carbon black 20% LCP and 2% CB required for maintaining electrical conductivity at high shear rates CB percolation network located on LCP particles 1170 

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Conducting Polymer Blends, Composites, and Colloids. Incorporation of conducting polymers into multicomponent systems allows the preparation of materials that are electroactive and also possess specific properties contributed by the other components. Dispersion of a conducting polymer into an insulating matrix can be accompHshed as either a miscible or phase-separated blend, a heterogeneous composite, or a coUoidaHy dispersed latex. When the conductor is present in sufftcientiy high composition, electron transport is possible. 

In a molded polymer blend, the surface morphology results from variations in composition between the surface and the bulk. Static SIMS was used to semiquan-titatively provide information on the surface chemistry on a polycarbonate (PC)/polybutylene terephthalate (PBT) blend. Samples of pure PC, pure PBT, and PC/PBT blends of known composition were prepared and analyzed using static SIMS. Fn ment peaks characteristic of the PC and PBT materials were identified. By measuring the SIMS intensities of these characteristic peaks from the PC/PBT blends, a typical working curve between secondary ion intensity and polymer blend composition was determined. A static SIMS analysis of the extruded surface of a blended polymer was performed. The peak intensities could then be compared with the known samples in the working curve to provide information about the relative amounts of PC and PBT on the actual surface. 

As already indicated above, what one may consider a surface depends on the property under consideration. Adhesion is very much an outer atomic layer issue, unless one is dealing with materials like fibreboard in which the polymer resin may also be involved in mechanical anchoring onto the wood particles. Gloss and other optical properties are related to the penetration depth of optical radiation. The latter depends on the optical properties of the material, but in general involves more than a few micrometer thickness and therewith much more than the outer atomic layers only. It is thus the penetration depth of the probing technique that needs to be suitably selected with respect to the surface problem under investigation. Examples selected for various depths (< 10 nm, 10 s of nm, 100 nm, micrometer scale) have been presented in Chapter 10 of the book by Garton on Infrared Spectroscopy of Polymer Blends, Composites and Surfaces... 

A.Garton, Infrared spectrosocpy of polymer blends, Composites and Surfaces, Hanser Publishers, Munich, 1992. 

Definitions of terms related to polymer blends, composites, and multiphase polymeric materials (lUPAC Recommendations 2004), Pure Appl. Chem. 76, 1985-2007 (2004). Reprinted as Chapter 9, this edition. 

Definitions of terms related to polymer blends, composites, and multiphase polymeric materials... 

Definitions of Terms Related to Polymer Blends, Composites, and Multiphase Polymeric Materials (2004), 186... 

Then the content of the syringe was dispensed in a strip on a glass slide and a doctor blade was used to spread the solution in the orthogonal direction. The phase behavior of the blend can be determined directly by visual inspection of the sample (Fig. 2, right). Similarly, it was also possible to create gradients in both polymer blend composition and film thickness by accelerating the movement of the doctor blade when spreading the blend solution [8]. 

Fig. 13 Illustration of a method for producing polymer blend composition gradient libraries. A and B are the polymer solutions to be blended.

VIGNETTE 1.6 POLYMER COMPOSITES Polymer-Blend Composites as Thermodynamically Stable, Microstructured Materials... 

JL olymers are typically complex mixtures in which the composition depends on polymerization kinetics and mechanism and process conditions. As we enter the twenty-first century, polymeric materials are becoming even more complex, consisting of polymer blends, composites, and branched and grafted structures of unusual architecture. To obtain polymeric materials of desired characteristics, polymer processing must be carefully controlled and monitored. Furthermore, we need to understand the influence of molecular parameters on polymer properties and end-use performance. As a result, we are faced with unprecedented... 

POLYMER BLENDS, COMPOSITE MATERIALS, AND ADDITIVES FOR POLYMERS... 

Kadla, J.F. Kubo, S. Lignin-based polymer blends analysis of intermolecular interactions in lignin-synthetic polymer blends. Composites, Part A Appl. Sci. Manuf. 2004, 35 (3), 395-400. 

GaxtonA,InfraredSpectroscopy of Polymer Blends, Composites andSuifaces,Manchen, Carl Hanser Verlag, 1992. 

Garton, A. (1992) Infrared Spectroscopy of Polymer Blends, Composites and Surfaces, Munich Hanser-Verlag. 

The International Union of Pure and Applied Chemistry (lUPAC) formed a Subcommission on Nomenclature of Macromolecules in 1952 and has proceeded to study various topics related to cyclic polymers, blends, composites, cross-linked polymers, block copolymers, etc. lUPAC periodically reports its decisions regarding nomenclature (1, 7, and ). Even so, these rules have not been generally accepted for common polymers by the majority of those in polymer science. 

Garton A (1992) Infrared Spectroscopy of polymer blends, composites and surfaces. Hanser, Munich... 

Polymer Blend Composition lype of Coupling References... 

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