2_COMPOSITE MATERIALS 1

2_COMPOSITE MATERIALS 1

1. combination of two or more materials that results in better properties than those on the individual components use alone.

   • It's properties depend
     • Properties of the matrix and the Reinforcement, Reinforcement Content, Reinforcement Orientation, Production Method.
       • Classification
         • The Shape of the constituent
           • Fibrous Composites
             • Fibers
               • Continuos
               • Discontinuos
                 • Aligned
                 • Disoriented
           • Particulate Composites.
             • Reinforcement
               • Equiaxed Particles
           • Structural Composites.
             • Homogeneous materials + Composites
               • Sandwich Panels and Laminates
         • The Nature of the Constituent.
           • Organic Matrix
             • Low Density. Possibility of obtaining Complicated Parts . most commonly used today
           • Metalic Matrix
             • High thermal and electrical conductivity - Not absorb moisture - Greater wear resistance
           • Mineral Matrix
             • resist high temperatures
         • The Size of the Dispersed Phase.
           • Microcomposites
             • Micron 10^-6
               • processing difficulty, we can not obtain fibers or laminates.
           • Nanocomposites
             • Nanometer 10^-9
               • Molecular Level
       • Interphase Union
         • Mechanical Connection
           • Roughness between the two surfaces resulting in the union
         • Electrostatic bonding
           • This type of bonding occurs when one surface is positive and the other negative charge .
         • Chemical Union
           • Surface reinforcement has chemical groups compatible with chemical groups of the parent
         • Union by interdiffusion
           • The surface of the reinforcement and the matrix polymer chains have diffusing including
       • Architecture of organic matrix composites
         • Reinforced plastics
           • .They consist of matrices in which fiber reinforcements are introduced or particle type
         • Structural composites
           • Laminates and joined by an adhesive.
             • Laminate Orinetation
               • Unidireccional
               • Bidireccional:
               • Multidireccional
             • Sandwich Material
             • Honney Comb
   • Organic Matrix
     • Polymer
       • Thermosetting
         • Have covalent bonds formed on crosslinking or curing reaction .
           • They are easy to process before curing, Tenacious, more fragile than thermoplastic.
             • Unsaturated polyester resins.vinyl ester resins. phenolics. Epoxy.
       • Thermoplastic
         • Haven't permanent connections between chains
           • Difficult to process, High molecular, Good mechanical properties
             • Polypropylene ( PP). polyethylene terephthalate. Polycarbonates
   • Reinforcement
     • The fibers are most commonly used reinforcement
       • Fiberglass
         • tensile strength / density - Good value properties / cost - Dimensional stability - Ease of fabrication - Good thermal resistance
           • Types
             • D (dielectric)
             • C (chemical)
             • E (eléctrico)
             • R (resistance)
       • Carbon Fiber
         • Planes of hexagonal rings of carbon atoms covalently linked . The junction between planes is weak through Van der Waals force .
           • HM fibers ((High Modulus)
           • HT Fibers (High Toughness)
       • Polymeric fibers
         • Kevlar
         • Polyethylene fibers

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