METHOD OF DETERMINING RESISTANCE OF ORGANIC POLYMERS TO DEGRADATION INDUCED BY VARIOUS FACTORS Russian patent published in 2019 - IPC G01N17/00 G01N3/00 G01N33/44 C12Q1/02 

FIELD: physics; chemistry.

SUBSTANCE: invention relates to mechanical property analysis of materials. Method involves preparation of a sterile dense nutrient medium (SDNM, which is an aqueous solution with pH 7.2±0.3, containing 13–19 g/l of agar-agar + 8–12 g/l of sucrose + 1.3–1.9 g/l of NH₄NO₃ + 0.4–0.6 g/l of KH₂PO₄ + 0.4–0.6 g/l of NaH₂PO₄ + 0.6–0.8 g/l of (NH₄)₂SO₄ + 0.18–0.22 g/l of Mg(NO₃)₂ + 0.05–0.07 g/l of FeCl₃ + 0.018–0.022 g/l of CaCl₂), preparation of a dense nutrient medium with test microorganisms (MDNM consisting of SDNM with a solid colony of Rhodotorula sp VKM Y-2993D grown on its surface), incubating samples of test materials on surface of said media for 1–2 months at room temperature and 95±5 % moisture content and measurement of mechanical properties of samples before and after their incubation. Evaluation of resistance of test materials to degradation induced by various factors is carried out in accordance with values of coefficients K_MR, K_XP and K_BR, which are calculated by following formulas: K_MR=100×(σ_I-σ_E)/σ_E, K_XP=100×(σ_K-σ_I)/σ_I and K_BR=100×(σ_B-σ_K)/σ_K, where σ_E ^_ strength of reference materials with a predetermined degree of degradability, σ_I – strength of tested materials not incubated, σ_K – strength of tested materials after their incubation with SDNM, σ_B – strength of tested materials after their incubation with MDNM.

EFFECT: high information value and reliability of evaluating the action of a larger range of possible destructuring factors (including physical, chemical and microbiological) on a wider range of tested materials.

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