TSRC, Tob. Sci. Res. Conf., 2014, 68, abstr. 93

The pore size distribution of naturally porous cigarette papers and its relation to air permeability and diffusion capacity – Part 2

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

Regulations regarding the self-extinguishment of cigarettes and the upper limits on smoke yields have, in addition to air permeability, led to an appreciation of diffusion capacity as a further important parameter of cigarette paper. Air permeability and diffusion capacity are linked together by the porous structure of the cigarette paper. It is the aim of this study to investigate this link by establishing a correlation between the pore size distribution of naturally porous cigarette papers and their air permeability and diffusion capacity, respectively. To this end eight cigarette papers were selected which differed in permeability, diffusion capacity, fiber furnish, filler content and burn additive content. The pore size distribution of these papers was measured by mercury porosimetry before and after the papers had been exposed to 230°C for 30 minutes. The pore size distribution was multiplied with a Gaussian weighting function and integrated to obtain a weighted pore volume. The two parameters of the weighting function, center and width, were chosen to maximize the correlation of the weighted pore volume with air permeability and diffusion capacity, respectively. The results show correlation coefficients greater than 0.9 for air permeability and diffusion capacity. The optimal center values of the weighting functions were at a pore radius of 2.5 µm for air permeability and 1.0 µm for diffusion capacity. These results indicate that, in agreement with theoretical considerations, large pores are better correlated with air permeability, while small pores are more strongly correlated with diffusion capacity. The results may help to fine-tune cigarette paper properties to maintain compliance with regulations with fewer compromises regarding consumer acceptance.