Carbonization Behavior of Polycondensed Fused-Polynuclear Aromatics (COPNA) Resins Synthesized from the Mixture of Pyrene and Phenanthrene U sing Dimethyl-substituted Benzenedimethanols as Crosslinking Agents -Studies on COPNA Resin. VIII.-

Abstract

Polycondensed fused polynuclear aromatics (COPNA) resins, previously reported, were carbonized by heat treatment up to 2500°C and carbonization mechanism of COPNA resins linked with dimethyl-substituted of benzenedimethanols (DM-series) was investigated. Discussion was carried out in terms of the structure changes due to heat treatment and the results obtained were compared to those of COPNA resin linked with PXG (PXG-series).
The starting materials for carbonization were obtained by post-curing DM-series (cured at 120°C for 20 h) 200°C for 1 h.
The resultant resins were heat-treated, in a stream of nitrogen, to 1400°C at a heating rate of 5°Cimin and then from 1400 to 2500°C at 20°C/min.
PXG-series was carbonized in solid state through the whole process, while DM-series completely liquefied at 450°C. Optically anisotropic mesophase was observed in a microscopic section of DM-series treated at this temperature.
X-ray diffraction parameters of DM -series chars produced by the heat treatment at various temperature up to 2500°C revealed that they behave like graphitizing carbon: at 2500°C, d₍₀₀₂₎=O.3 36 nm, Lc = 33 rim.