TSRC, Tob. Sci. Res. Conf., 2014, 68, abstr. 92

The pore size distribution of naturally porous cigarette papers and its relation to air permeability and diffusion capacity – Part 1

delfortgroup AG, Papierfabrik Wattens GmbH & Co. KG, Wattens, Austria

In the tobacco industry, it is well known that porosity is one of the most significant physical properties of cigarette paper. There are indirect and direct methods to characterize this parameter. Measurement of the diffusion capacity and air permeability are indirect methods, where gases are transferred through the paper by concentration or pressure differences. Using mercury porosimetry, porosity is measured directly via the pore volume of the paper.

The aim of this study is to analyze the pore size distributions resulting from mercury porosimetry of eight different cigarette papers with different air permeabilities, fiber furnishes, filler contents, and burn additive contents. The pore size distribution was measured before and after heating the papers to 230°C for 30 minutes in the presence of air.

For a qualitative analysis, pore size distributions have been divided into three sections based on radius: 0.04-0.8 µm (section 1), 0.8-3 µm (section 2), and 3-30 µm (section 3). Comparing the pore size distributions for the unheated paper samples with different permeabilities, we found that papers with low air permeability showed higher pore volumes in section 1, while papers with high permeability showed higher pore volumes in section 2. Variation of the filler content causes changes in the pore volume only in sections 1 and 3. As expected, the influence of burn additive content on the pore size distribution was small in all sections. By heating the papers before mercury porosimetry analysis, the overall pore volume increases compared to unheated papers.

The results show how the pore size distribution of cigarette paper can be influenced by tools available to the cigarette paper manufacturer such as the paper composition and paper properties.