Measurement of Gas Diffusion Capacity of Cigarette Papers

Apparatus suitable for measuring gas diffusion capacity of cigarette paper was assembled and evaluated. The apparatus provides semi-automated means for measuring the concentration of carbon dioxide diffusing through a small area of the paper, and computation of a paper thickness-dependent diffusion capacity of the sample. Measurements are rapid and can be made in about 30 s. Diffusion capacity measurements were repeatable and reproducible to within about 1%. Variability of the diffusion capacity values was much lower than that observed for permeability measurements. For these reasons, the apparatus is useful for quality assessment and research applications. Diffusion capacity was measured for cigarette papers of inherent permeability ranging from 6 to 62 cm/min. As expected from prevailing theory, the diffusion capacity values generally increased with permeability. The diffusion capacity measured for electrostatically perforated papers was only slightly higher (about 6-11%) than the unperforated base paper despite large increases in permeability. This result indicates that diffusion capacity is governed by small pores in the paper. The apparatus is capable of measuring banded areas of papers designed for reduced ignition propensity. Diffusion capacity values for banded areas were lower than those of non-banded paper of similar permeability, suggesting that the band material preferentially occludes small pores in the paper.