The influence of lignin on the properties of organic and carbon gels synthesized by sol-gel polymerization of a mixture of formaldehyde and polyphenols isolated by various solvents from the larch bark was investigated.

The porous structure and adsorption properties of polymer gels synthesized from mixtures of formaldehyde and ethanol extracts of bark by varying the pH value of initial solutions in the range of 4 to 12 were studied by BET and SEM methods. It was shown that an increase in pH value leads to the formation of organic gels with a more compacted texture and narrow pores. Carbonization of organic gels at 900°C promotes the significant development of the specific surface area (up to 477 m²/g) of the obtained carbon gels.

It was found that the addition of lignin in an amount of 10% wt. to the polyphenols extracted by water from the larch bark improves the texture characteristics of the obtained organic and carbon gels and increases theirs elasticity and strength. But the increase of the lignin content to 20-30% wt. reduces the total porosity and the total pore volume of the obtained gels. The effect of lignin on the properties of gels, obtained with the use of polyphenols extracted from larch bark by water–alkaline solution, is less pronounced.