Abstract: A filter has a urethane-based main chain having a repeat unit of the formula, R?—NH—COO—R—O—NHn, wherein the R group and the R? group are an aliphatic chain and an aromatic group respectively. The R group, R? group, and —NH— moiety in the repeat unit serve as reactive radicals for trapping cyanides, phenols, or polynuclear aromatic compounds, wherein the reactive radicals are revealed through an extraction process to remove a plurality of contaminants from the urethane-based main chain.

Abstract: A method for manufacturing a filter is introduced. Firstly, a polyurethane material including a urethane-based main chain having a repeat unit of the formula, (R—NH—COO—R—O—NH)n, with a plurality of contaminants absorbed around the urethane-based main chain is provided. Then, an extraction is performed to remove the contaminants from the urethane-based main chain so as to reveal a plurality of absorption sites for trapping cyanides, phenols, or polynuclear aromatic compounds.

Abstract: Disclosed herein is a filter for use with tobacco products, such as cigarettes, cigars, and pipes, which selectively absorbs toxic compounds and carcinogenic polynuclear aromatic compounds passing through it, but which permits most low molecular weight species, and in particular nicotine, to pass through. The filter is made from a middle-density polyurethane foam which is pre-treated to increase the number of binding sites for polynuclear aromatic compounds.

Abstract: Disclosed herein is a filter for use with tobacco products, such as cigarettes, cigars and pipes, which selectively absorbs toxic compounds and carcinogenic polynuclear aromatic compounds passing through it, but which permits most low molecular weight species, and in particular nicotine, to pass through. The filter is made from a middle-density polyurethane foam which is pre-treated to increase the number of binding sites for polynuclear aromatic compounds.