Accession Number : ADA140912

Title :   Development of High Modulus Polydiacetylene Fibres for Use in Fibre-Reinforced Composites.

Descriptive Note : Final technical rept.,


Personal Author(s) : Young,R J ; Galiotis,C ; Yeung,P H J

PDF Url : ADA140912

Report Date : Feb 1984

Pagination or Media Count : 67

Abstract : The relationship between structure and mechanical properties in polydiacetylene single crystal fibres has been studied in detail. It has been shown by transmission electron microscopy that the fibres have a high degree of internal perfection with the polymer molecules aligned parallel to the fibre axes. The fibres of the di-carbazolyl derivative investigated were found to have a Young's modulus of 45 GPa and fracture strengths of up to 1.5 GPa, the strength being controlled by defects such as surface steps. It was shown that the stiffness of the polymer backbone is similar to that of polyethylene and the theoretical strength of the polydiacetylene single crystal fibres has been determined to be about 3 GPa, corresponding to a fracture strain of between 6% and 8% and a force required to break molecules of the order of 3nN. A model composite system consisting of one polydiacetylene single crystal fibre in an epoxy resin matrix has been subjected to tensile strain parallel to the fibre direction. The resonance Raman strain measurement technique has been extended to measure the distribution of fibre strain in composites containing bundles of polydiacetylenes in both an epoxy matrix and a glass-fibre/epoxy/composite. The deformation of epoxy composites containing high volume fractions of polydiacetylene single crystal fibres has been investigated both tension and compression.

Descriptors :   *Polymers, *Acetylenes, *Fibers, *Fiber reinforced composites, Mechanical properties, Structural properties, Single crystals, Molecular structure, Modulus of elasticity, Fracture(Mechanics), Strength(Mechanics), Stiffness, Strain(Mechanics), Thermal stability, Creep strength, Epoxy resins, Matrix materials, Epoxy composites, Tensile properties, Deformation, Raman spectroscopy, Electron microscopy

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE