D.A. Astashkin, V.A. Muftakhov, N.A. Prokudina
Natural composites and polymers
DOI 10.47148/0016-7894-2026-4-71-75
Key words: carbonate rock; natural composites; polymers; organic-mineral associations; crystalline structure.
For citation: Astashkin D.A., Muftakhov V.A., Prokudina N.A. Natural composites and polymers. Geologiya nefti i gaza. 2026;(4):71–75. DOI: 10.47148/0016-7894-2026-4-71-75. In Russ.
A critical analysis is presented of the hypothesis proposed in a number of studies, that rock-forming carbonates are polymeric (geobiopolymeric) in nature. The terminological and physicochemical distinctions between naturally occurring organomineral associations and true high-molecular-weight compounds (polymers) are substantiated. It is also demonstrated that the effects observed in carbonate rocks can be consistently explained within the framework of the multiphase composite concept. The authors provide a systematic examination of four principal arguments in support of the polymer hypothesis, namely: presence of globular structures in electron micrographs; swelling of carbonate grains in organic solvents; the unresolved S4–S5 peaks observed in Rock-Eval pyrolysis; and deviations in elemental composition from the stoichiometric composition of calcite, together with the presence of organomineral associations containing impurities such as Si and S. For each of these arguments, alternative physically sound interpretations are proposed. Particular attention is paid to the fundamental difference between a composite and a polymer. The authors emphasize that single high-molecular-weight compound is a single-phase, isotropic material in which monomeric units are linked by covalent bonds, whereas the objects described in a number of studies are two-phase aggregates consisting of a crystalline core (CaCO₃) and an organic shell, with each phase retaining its own characteristic properties. The effects observed can be completely explained by formation of organomineral composites, in which the mineral core retains its crystalline structure and properties, while the organic shell exhibits its own characteristic behavior, including swelling and thermal degradation. Such a system should be properly classified as an organomineral composite rather than a polymer.
Dmitrii A. Astashkin ORCiD Scopus
Candidate of Geological and Mineralogical Sciences,
Deputy Director
Head of the Research and Analytical Center
Aprelevka branch of the All-Russian Scientific-Research Geological
Oil Institute (VNIGNI),
1st Ketritsa ul., Aprelevka, 143360, Russia
e-mail: astashkin@vnigni.ru
SPIN-code: 1689-9512
Vyacheslav A. Muftakhov ORCiD Scopus
Candidate of Geological and Mineralogical Sciences,
Leading Researcher
Aprelevka branch of the All-Russian Scientific-Research Geological
Oil Institute (VNIGNI),
1st Ketritsa ul., Aprelevka, 143360, Russia
e-mail: v.muftahov@vnigni.ru
SPIN-code: 2310-4993
Nina A. Prokudina ORCiD Scopus
Candidate of Chemical Sciences,
Leading Researcher
Aprelevka branch of the All-Russian Scientific-Research Geological
Oil Institute (VNIGNI),
1st Ketritsa ul., Aprelevka, 143360, Russia
e-mail: n.prokudina@vnigni.ru
SPIN-код: 5811-1556
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Section: Discussions