GLASSY CARBON FROM SULFONATED POLYSTYRENE

For the purpose of preparing glassy carbon from thermoplastic resins, spherical particles of polystyrene were made infusible by the sulfonation and pyrolyzed at 200~1600°C. The following three methods were performed for sulfonation; (a) sulfonation of polystyrene particles with SO, gas, (b) sulfonation of the polystyrene solution in C2H4Cl2 with the mixture of fuming sulfuric acid and C2H4Cl2 (1:1), and (c) direct sulfonation of polystyrene particles with fuming sulfuric acid. The last method was most effective to obtain infusible cross-linked polymer as shown in Table 1. Spherical hard carbon particles of 100~150A diameter were obtained by pyrolyzing the sulfonated polystyrene at high temperatures. Carbonization process were pursued by micrograph, the measurement of weight loss, elemental analysis, and so on (Figs. 1~3). X-ray diffraction patterns of carbon formed were very analogous to those of a phenolic resin carbon, and the crystal parameters, d602, Lc, and La showed the characteristic values for non-graphitizable carbon. The stability against air oxidation measured by differential thermal analysis was comparable to that of glassy carbon (Fig. 4). BET surface area density and micro-Vicker's hardness were also measured as a function of heat treatment temperature (Figs. 5~7), and were compared with the results for glassy carbon. As the results the carbonaceous products from sulfonated polystyrene were found to be non-graphitizable hard carbon with the functions equivalent to usual glassy carbon from thermosetting resins. © 1979, The Chemical Society of Japan. All rights reserved.