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NONMETALLIC STRUCTURAL MATERIALS
Polymers (plastics) Ceramics Glass (amorphous materials)
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Plastics: composition
Binding material Filling material (powder, fibers, sheets) Stabilizers Plastifiers Hardeners Special additives (dyes, greases, antistatics, additives against burning, against a mildew)
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Plastics: properties Low density High unit strength σT/γ
Chemical durability Electrical insulators Heat insulators Less labour input of processing (a product and a material are made simultaneously; finishing operations are not necessary) Little waste (material utilization rate not less than 0.9)
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Plastics: basic lacks Limited thermostability (the maximum temperature of operation for thermoplastics is 250 °С, for thermosets nearby 400 °С) Low stiffness E and toughness KCU Propensity to ageing (properties change eventually)
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Structure of polymers Macromolecules: Scheme of linear macromolecula
polyethylene polyvinyl-chloride Structure of macromolecules: а – linear; b – branched; c – cross-linked; d – network а b c d
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Structure of polymers Rotation of segments in a macromolecula:
Chain-packed structure: Crystals: Various crystal shapes: spherolith fibrillas
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Behaviour of polymers upon heating
Thermomechanical curves: а) amorphous thermoplastic; b) crystalline thermoplastic; c) thermosetting polymer
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Behavior of polymers under loading (tension diagrams)
а) amorphous thermoplastic; b) thermosetting polymer; c) crystalline thermoplastic
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