Other thermoplastic matrices

Thermoplastic polymers such as PEEK and PEI have been successfully used [60,61] as alternative polymer matrices, but it is doubtful whether their high cost can ever be justified. 

Polyarylacetylene, formed from the polymerization of diethynylbenzene [62,63] is non-graphitizing, but does have a char yield of 88% and can be catalytically graphitized at lower temperatures using carborane (C2B10H12), a boron containing compound. 

Other resins have been investigated and include polybenzunidazole (PBI) [48], which has a 73% carbon yield. 

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Two important types of elastomeric polyolefin blends are reactor-made iPP/ EPR blends and postreactor blend iPP/EPDM. The latter is called thermoplastic vulcanizates (TPVs), produced by dynamic vulcanization of blends containing a thermoplastic and an elastomer. To make iPP/EPDM TPV, the two polymers PP and EPDM are mixed with curatives, such as peroxides, phenolic resins, or sulfur with accelerators, and dynamically cured in an extmder resulting in a blend consisting of micrometer-sized elastomer particles dispersed in the PP matrix (20-24). Paraffinic oils are added in the melt mixing process for viscosity control and cost. In iPP/ EPDM TPV, the crystalline iPP resin is normally the minor phase. Recently, polyolefin plastomers have been added to the class of elastomeric polyolefin blends. Polyolefin plastomers are ultralow molecular weight linear low density polyethylenes (ULMW-LLDPE). Nonelastomeric polyolefin blends are blends of polyolefins with mostly nonpolyolefin (other thermoplastic) matrices as mentioned earlier. 

Although in the present review we have mainly investigated the influence of properly functionalized PO on commodity polyesters, it must be stressed that other thermoplastic matrices (PA6, PA6,6 etc.) have also been modified with a rubbery functionalized component. Generally, two different blending routes, in the case of polyamides, are utilized ... 

The microwave susceptors in this initial study have been carbon black, magnetite, lead zirconate titanate, and silicon carbide. The polymeric matrix for these trials has been mainly high density polyethylene, which is a nonpolar polymer without any absorption of microwave radiation. Other thermoplastic matrixes like polyamide 6 (PA6), polybutylene terephthalate (PBT) and metallocene polypropylene (m-PP) have been used as reference material. 

Technology Descriptions The use of thermoplastic solidification systems in radioactive waste disposal has led to the development of waste containment systems that can be adapted to industrial waste. In processing radioactive waste with bitumen or other thermoplastic material (such as paraffin or polyethylene), the waste is dried, heated and dispersed through a heated, plastic matrix. The mixture is then cooled to solidify the mass. 

Shear yield behaviour of polymer melts containing plate-like filler particles is also prevalent and is clearly shown in Fig. 8 for talc-filled polystyrene. In this system an estimate was made of shear yield values, which were found to increase with increasing particle loading and decreasing particle size. These results are compared with reported yield values for other particulate-filled polymers in Table 2. It is evident that shear yield values also depend on the particle type and thermoplastic matrix used. 

The carbon chain is in a planar zigzag orientation and forms an orthorhombic lattice with interpenetration of adjacent chains.61 As a result of this structure, ETFE has an exceptionally low creep, high tensile strength, and high modulus compared to other thermoplastic fluoropolymers. Interchain forces hold this matrix until the alpha transition occurs at about 110°C (230°F), where the physical properties of ETFE begin to decline and more closely resemble perfluoropolymers properties at the same temperature. Other transitions occur at -120°C (-184°F) (gamma) and about -25°C (-13°F) (beta).62... 

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]. 

The reinforcement of polypropylene and other thermoplastics with inorganic particles such as talc and glass is a common method of material property enhancement. Polymer clay nanocomposites extend this strategy to the nanoscale. The anisometric shape and approximately 1 nm width of the clay platelets dramatically increase the amount of interfacial contact between the clay and the polymer matrix. Thus the clay surface can mediate changes in matrix polymer conformation, crystal structure, and crystal morphology through interfacial mechanisms that are absent in classical polymer composite materials. For these reasons, it is believed that nanocomposite materials with the clay platelets dispersed as isolated, exfoliated platelets are optimal for end-use properties. 

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