✍ Scribed by E. Fitzer; J. Kalka
No coin nor oath required. For personal study only.
The pore volume and the pore structure of chars made from poly-2,6dimethylphenylene oxide (PPO) were studied by adsorption measurements. The chars were prepared by pyrolysis of the thermoplast as well as of the pre-oxidized crosslinked polymer under various conditions (vacuum, nitrogen, heating rate between 15°C and 200°C/hr). The micropore volume is explained by molecular probes as being slit shaped with pore heights between 4 and 6 .~. It is found from the hysteresis of the desorption isotherms of nitrogen that diverging pores with diameters of up to 30 .~ connectedby the above mentioned small slits amount to 5 to 8 per cent of the total micropore volume. Chars of the pre-oxidized PPO can be used as molecular sieves for aromatic compounds. Uniform slit pores of 5 to 6 A width can be attained by optimization of the pre-oxidation conditions. Residues of 0.24 cm3/g were obtained as maximum micropore volume in chars heat treated up to 600°C. A structure model of disordered carbons is proposed, based on the adsorption measurements and on the pyrolysis mechanism.
📜 SIMILAR VOLUMES