High Performance Fibers and Fibrous materials Yiping Qiu Donghua university
High Performance Fibers and Fibrous materials Yiping Qiu Donghua University
Outline ● Carbon fibers ● Glass fibers ● Aramid fibers o Ultra High Modulus polyethylene fibers ● Carbon nanotubes ● Ceramic fibers o Mechanical properties of fibers
Outline ⚫ Carbon fibers ⚫ Glass fibers ⚫ Aramid fibers ⚫ Ultra High Modulus Polyethylene fibers ⚫ Carbon nanotubes ⚫ Ceramic fibers ⚫ Mechanical properties of fibers
Carbon fibers ● Reading assignment o hull and Clyne. Chapter 2 Fibres and Matrices. An Introduction to Composite Materials, 2nd ed. Cambridge University Press. Pages 9-30
Carbon fibers ⚫ Reading assignment ⚫ Hull and Clyne, Chapter 2 Fibres and Matrices, An Introduction to Composite Materials, 2nd ed. Cambridge University Press. Pages 9 –30
Carbon fibers o Manufacturing processes o Structure and properties
Carbon fibers ⚫ Manufacturing processes ⚫ Structure and properties
Carbon fibers Manufacturing processes o Thermal decomposition of fibrous organic precursors ● Extrusion of pitch
Carbon fibers – Manufacturing processes ⚫ Thermal decomposition of fibrous organic precursors ⚫ Extrusion of pitch
Carbon fiber manufacturing processes Rayon based carbon fibers Stabilization at 400 C in O2, depolymerization aromatization Carbonization at 400-700 C in an inert atmosphere Stretch and graphitization at 700-2800 C (improve orientation and increase crystallinity by 30-50%)
Carbon fiber manufacturing processes – Rayon based carbon fibers Stabilization at 400°C in O2 , depolymerization & aromatization Carbonization at 400-700°C in an inert atmosphere Stretch and graphitization at 700-2800°C (improve orientation and increase crystallinity by 30-50%)
Carbon fiber manufacturing processes PAN (polyarylonitrile) based carbon fibers ● Pan fibers Stabilization at 200-300 C in O2, depolymerization &e aromatization, converting thermoplastic PAN to a nonplastic cyclic or ladder compound Carbonization at 1000-1500 C in an inert atmosphere to get rid of noncarbon elements Stretch and graphitization at >1800 C, formation of turbostratic structure
Carbon fiber manufacturing processes – PAN (polyarylonitrile) based carbon fibers ⚫ PAN fibers Stabilization at 200-300°C in O2 , depolymerization & aromatization, converting thermoplastic PAN to a nonplastic cyclic or ladder compound Carbonization at 1000-1500°C in an inert atmosphere to get rid of noncarbon elements Stretch and graphitization at >1800°C, formation of turbostratic structure
Stabilization of pan fibers Figure 2 Intermolecular interaction of nitrile groups
Stabilization of PAN fibers
Pitch based carbon fibers o pitch- high molecular weight byproduct of distillation of petroleum heated >350 C. condensation reaction, formation of mesophase (Liquid crystal): Structure of mesophase pitch melt spinning into pitch fibers Oxidation at a temperature below softening temperature conversion into graphite fibers at 2000 C without tension
Pitch based carbon fibers ⚫ pitch - high molecular weight byproduct of distillation of petroleum – heated >350°C, condensation reaction, formation of mesophase (Liquid crystal): Structure of mesophase pitch melt spinning into pitch fibers Oxidation at a temperature below softening temperature conversion into graphite fibers at ~2000°C without tension
Pitch based carbon fibers Advantages Much higher degree of graphitization than polymer based carbon fibers High strength and modulus o High thermal conductivity: even much better than copper
Pitch based carbon fibers – Advantages ⚫ Much higher degree of graphitization than polymer based carbon fibers ⚫ High strength and modulus ⚫ High thermal conductivity: even much better than copper
