Structural polymers thermoplastic-matrix materials

Fiber-reinforced polymer structures are typically laid up by hand, consolidated (compressed together) with the polymer resin matrix material, and cured with heat and pressure. This method is capable of producing uniquely shaped, strong, and lightweight structural pieces. Fiber-reinforced polymers can also be used in mass-production methods thermoplastic materials can be employed to produce many relatively simple shapes that do not call for high strength. Variations on these methods, such as extrusion and pultrnsion, represent combinations of these methodologies. 

Pultrusion. Another method by which thermoplastic fiber-reinforced polymers are produced is pultrusion. In pultrusion, an appropriately designed bundle of continuous fiber strands is drawn through a die along with a molten thermoplastic matrix material. The die serves to consolidate the material combination, and as the matrix material solidifies on exiting the die, a continuous fiber-reinforced structure is produced. Examples of pultruded products include fiberglass rods and reinforced water hoses. 

Natural fibers-reinforced polymer matrixes provide more alternatives in the materials market due to their unique advantages. Poor fiber-matrix interfacial adhesion may affect the physical and mechanical properties of the resulting composites due to the surface incompatibihty between hydrophilic natural fibers and non-polar polymers. The results presented in this chapter focus on the properties of palm and pineapple fibers in terms of their physical and chemical structure, mechanical properties and processing behavior. The final properties of these fibers with thermoplastics matrixes are also presented, paying particular attention to the use of physical and chemical treatments for the improvement of fiber-matrix interaction. 

In most of the above composites, as polymer matrices, thermoset polymers have gained major industrial importance as matrix materials. The use of thermoplastic matrices for aramid FRPs is being increasingly studied recently. There are also a vast number of applications where aramid fibers are the sole constituent, e.g., in protective apparel, armor systems, ropes, etc. During the last decade the aramid containing FRP composites have developed into economically and structurally viable construction materials for buildings and bridges [4]. 

Multiphase or multicomponent polymers can clearly be more complex structurally than single phase materials, for there is the distribution of the various phases to describe as well as their internal structure. Most polymer blends, block and graft copolymers and interpenetrating networks are multiphase systems. A major commercial set of multiphase polymer systems are the toughened, high impact or impact modified polymers. These are combinations of polymers with dispersed elastomer (rubber) particles in a continuous matrix. Most commonly the matrix is a glassy amorphous thermoplastic, but it can also be crystalline or a thermoset. The impact modified materials may be blends, block or graft copolymers or even all of these at once. 

Nanocomposites based on thermoplastic matrix and containing natural, laminated inorganic structures are referred to as laminated nanocomposites. Such materials are produced on the basis of ceramics and polymers however with the use of natinal laminated inorganic structiues such as, montmorillonite or vermiculite which are present for example, in clays. A layer of filler 1 tun thick is satinated with monomer solution and later polymerized. The laminated nanocomposites in comparison with initial polymeric matrix possess much smaller permeability for liquids and gases. These properties allow applying them to medical and food processing indnstry. Snch materials can be used in manufactine of pipes and containers for the carbonated beverages. 

Polymer features that lead to miscibility with polysulfone should be further quantihed to be able to optimize the membrane separation characteristics of polymer mixtures. On the other hand, in the case of immiscible polysulfone blends, it is desirable to better define the features of the blend components that lead to a particular morphology. Some of those features are perhaps going to be different in the case of thermoplastic and thermoset matrix materials, but viscosity is certainly going to be relevant in both cases. However, in order to best utilize the polysulfone blends that have been discussed in this chapter, more work is required to better comprehend their structure-property-processing relationships. 

Materials with totally new property combinations may be achieved by blending two or more polymers together. Through blending of thermotropic main-chain LCPs with engineering thermoplastics, the highly ordered fibrous structure and good properties of LCPs can be transferred to the more flexible matrix polymer. LCPs are blended with thermoplastics mainly in order to reinforce the matrix polymer or to improve its dimensional stability, but LCP addition may modify several... 

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