Matrix resin continuous phase

A nanocomposite material can be defined as one that consists of two or more different material components, at least one of which has a domension (i.e., length, width, or thickness) below 100 nm. There are many types of nanocomposites presently under research and development including polymer/inor-ganic particle, polymer/polymer, metal/ceramic, and inorganic-based nanocomposites. However, the first named one, commonly called polymer nanocomposite (PNC) and defined as the comhination of a polymer matrix resin (continuous phase) and inclusions having at least one dimension less than 100 nm, is the only type of nanocomposite to date that has seen any significant commercial activity. 

Research on the pyrolysis of thermoset plastics is less common than thermoplastic pyrolysis research. Thermosets are most often used in composite materials which contain many different components, mainly fibre reinforcement, fillers and the thermoset or polymer, which is the matrix or continuous phase. There has been interest in the application of the technology of pyrolysis to recycle composite plastics [25, 26]. Product yields of gas, oil/wax and char are complicated and misleading because of the wide variety of formulations used in the production of the composite. For example, a high amount of filler and fibre reinforcement results in a high solid residue and inevitably a reduced gas and oiFwax yield. Similarly, in many cases, the polymeric resin is a mixture of different thermosets and thermoplastics and for real-world samples, the formulation is proprietary information. Table 11.4 shows the product yield for the pyrolysis of polyurethane, polyester, polyamide and polycarbonate in a fluidized-bed pyrolysis reactor [9]. 

Dental Composite Restoratives. Polymeric restoratives have three major components an organic resin matrix, an inorganic filler modified with a coupling agent, and a suitable polymerization initiator system. The formulation used to produce the organic matrix, or continuous phase, is made up of free-radical polymerizable monomers. The monomer mostly used in the formulations for both anterior and posterior resins is BisGMA (Fig. 7), or alternatively formulated with... 

As noted earlier, for the most part, the resulting materials from the use of reinforcements are composites, which are materials that contain strong fibers embedded in a continuous phase. The fibers are called reinforcement and the continuous phase is called the matrix. While the continuous phase can be a metallic alloy or inorganic material, it is typically an organic polymer that is termed a resin. Composites can be fabricated into almost any shape and after hardening, they can be machined, painted, etc., as desired. 

Many properties of composites filled with nonreinforcing fillers, such as coefficient of expansion, heat deflection, and specific heat, may be estimated from the rule of mixtures. Thus the coefficient of expansion of the composite, ae, is related to the sum of the coefficients of expansion of the continuous phase or resin matrix m and the discontinuous phase or filler/times their fractional volumes V and (1 — V)% respectively, as follows ... 

Engineering thermoplastics have also been used in preimpregnated constructions. The thermoplastic is thoroughly dispersed as a continuous phase in glass, other resins, carbon fibers (qv), or other reinforcement. Articles can be produced from these constructions using thermoforming techniques. For example, the aerospace industry uses polyetheretherketone (PEEK) in woven carbon-fiber tapes (26). Experimental uses of other composite constructions have been reported (27) (see also COMPOSITE MATERIALS, POLYMER-MATRIX). 

These blends can take a number of different forms. The added resin may be reacted with the epoxy resin, or it may be included as an unreacted modifier. The modifier may be blended into a continuous phase with the epoxy resin (epoxy alloys) or precipitated out as a discrete phase within the epoxy resin matrix (as is generally done in the case of toughening modifiers). Epoxy hybrid adhesives are often used as film (supported and unsupported) or tape because of the ease with which formulated systems can be dissolved into solvent and applied to a carrier or deposited as a freestanding film. Some systems, notably epoxyurethanes and epoxy-poly sulfides, can be employed as a liquid or paste formulation because of the low-viscosity characteristics of the components. 

Syntactic foams are made using a resin matrix to which has been added hollow spheres of various materials. The resultant product is a foamlike material made without the use of a blowing agent. The most common matrix resins are epoxies and polyesters, although urethanes, PVC plastisols, and phenolic resins have also been used. Indeed, any polymer that can be made liquid, either before final polymerization or by heat, can be used as the binding resin. In syntactic foams the resin matrix is the continuous phase and the hollow spheres the discontinuous phase. 

They consist of particles of crosslinked rubber, covered by a layer of graft resins (elastomer phase) embedded in a continuous matrix (resin phase). It is well known that the elastomer phase has a major effect on the ABS polymers. Varying the structure of the elastomer phase changes the properties of the resin. An increase in the elastomer phase induces the following changes in physical properties ... 

A variant of thermosetting has been described in that PPE resins are dissolved in epoxy resins. A variety of polymers can be dissolved in epoxy resins." In order to facilitate the processability of PPE, the PPE is dissolved in an epoxy resin as processing aid. After processing by kneading, the epoxy resin is cured. In contrast to other approaches where the thermoplastic polymer acts as a toughener for the epoxy matrix, the amount of epoxy resin added can be adjusted so that the PPE will form the continuous phase in the final state. 

Reinforced pol)nners are those to which fibers have been added that increase the physical properties—especially impact resistance and heat deflection temperatures. Glass fibers are the most common additions, but carbon, graphite, aramid, and boron fibers are also used. In a reinforced polymer, the resin matrix is the continuous phase, and the fiber reinforcement is the discontinuous phase. The function of the resin is to bond the fibers together to provide shape and form and to transfer stresses in the structure from the resin to the fiber. Only high-strength fibers with high modulus are used. Because of the increased stiffness resulting from the fiber... 

Once the use was postulated of solid domains (second-phase particles) in polystyrene to produce a high impact plastic, it was reahzed that this concept could work for epoxy resins if discrete, so-called second-phase particles could be produced throughout the continuous phase of the cured adhesive matrix. 

Composite kam- pa-z3t, kom-, esp British kam-po-zit [L compositus, pp of compo-nere] (1563) adj. (1) An article or substance made up of two or more distinct phases of different substances. In the plastics industry the term applies broadly to structures of reinforcing members dispersed phase) incorporated in compatible resinous binders continuous phase). Such composites are subdivided into classes on the basis of the reinforcing constituents laminate, particulate (the dispersed phase consists of unlayered fibers) flake (flat flakes forming the dispersed phase) and skeletal (composed of a continuous skeletal matrix filled by a resin). (2) Hard or soft constructions in which the fibers themselves are consolidated to form structures rather than being formed into yarns. Rigidity of these constructions is controlled by the density, the modulus of the load-bearing fibers, and the fraction of fusible... 

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