2 ethylhexanoic acid

Rapeseed oil for the preparation of synthesized oil along with hydrogen peroxide (H₂O₂; 35% w/w) was supplied by FICHEMA s.r.o. Czech Republic. Methyl (R)-(+)-lactate for the methacryled methyl lactate synthesis was obtained from Hefei Home Sunshine Pharmaceutical Technology Co., Ltd., China. All other reactants used for the mixture thermoset synthesis were acquired from Sigma Aldrich, particularly: Formic acid (puriss. p.a.), triethylamine (≥99%), 4-Methoxyphenol (for synthesis), methacrylic anhydride (94%); potassium hydroxide (p.a.), 2-ethylhexanoic acid (for synthesis), potassium iodide (ACS reagent, ≥99.0%), and sodium thiosulfate (ReagentPlus^®, 99%). The solvent for NMR analyses (d-chloroform (CDCl₃; 99.8%)) was obtained from Sigma Aldrich as well.

1-Dodecanthiol (DDT, 98%) was obtained from Acros Organics; Zinc stearate (65%), Zinc oxide (99%) and Indium (III) acetate (In(Ac)₃, 98%), Silver (I) nitrate (AgNO₃, ≥99.5%), Oleic acid (OA, 90%), 1-Octadecene (ODE, 90%), Oleylamine (OlAm, 70%), 2-Ethylhexanoic acid (99%), Thiourea (99%), Triethyleneglycol dimethylether (98%), L-cysteine hydrochloride monohydrate (98%), Potassium hydroxide (KOH, 90%) were purchased from Sigma Aldrich (Saint Petersburg, Russian Federation). Organic cyanine dyes: 3,3′-diethylthiacarbocyanine iodide (Cy3) (95%) and 3,3′-diethylthiadicarbocyanine iodide (Cy5) (98%) were purchased from Sigma-Aldrich. Solvents: Isopropanol (99.8%), acetone (99.75%), and chloroform (99.9%) were obtained from Vekton (Saint Petersburg, Russian Federation). All chemicals were used without further purification. Ultrapure water (Milli-Q) was used throughout the experiments.

Acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid, hexanoic acid, 2-ethyl butyric acid and 2-ethyl hexanoic acid were purchased from Sigma-Aldrich (St. Louis, MO, USA). We used 2-ethyl butyric acid and 2-ethyl hexanoic acid as internal standards (IS) for final determination of the quantity of each compound present in fecal samples. Ethanol was purchased from Tianjin Damao Chemical Reagent Factory (Tianjin, China). Hydrochloric acid was from Tianjin Jindong Tianzheng Precision Chemical Reagent Factory (Tianjin, China). Ultra-pure water was generated using a Milli-Q water purification system (Millipore, USA). Antibiotics employed were cefdinir dispersible tablets (Shenzhen Zhijun Pharmaceutical Co., Ltd., production batch number A150103), and azithromycin dispersible tablets (Harbin Pharmaceutical Group, Sanchine Nuojie Pharmaceutical Co., Ltd., production batch number 1502224), which were provided by first teaching hospital of Tianjin university of TCM (Tianjin, China).

d-penicillamine (99%) and zinc (II) nitrate hexahydrate (99.998%), sodium sulfide nonahydrate (98%) were obtained from Acros Organics (Moscow, Russia); and indium (III) chloride (98%), silver (I) nitrate (≥99.5%), 1-dodecantiol (DDT), 1-octadecene (ODE), oleylamine (OA, 70%), ammonium hydroxide solution (25%), 3-mercaptopropionic acid (MPA, purity > 98%), 2-ethylhexanoic acid (99%), thiourea (99%), triethyleneglycol dimethylether (98%) were purchased from Sigma-Aldrich in Saint Petersburg, Russian Federation. Organic cyanine dyes: 3,3′-diethylthiacarbocyanine iodides (Cy3) and 3,3′-diethylthiadicarbocyanine iodide (Cy5) were purchased from Sigma-Aldrich in Saint Petersburg, Russian Federation. All chemicals were used without further purification. Ultrapure water (Milli-Q) was used throughout the experiments.

PLA granulate was supplied from Fillamentum Manufacturing Czech s.r.o., Hulín, Czech Republic. Measured polymer parameters were as follows: number-average molecular weight (M_n), 123,500 g/mol; weight-average molecular weight (MW), 235,300 g/mol; dispersity, 1.90. PHB powder was acquired from NAFIGATE Corporation a.s., Prague, Czech Republic. Measured polymer parameters were as follows: number-average molecular weight (M_n), 85,040 g/mol; weight-average molecular weight (MW), 211,400 g/mol; dispersity, 2.49. All measurements of polymer properties were measured via GPC (Agilent 1100, Santa Clara, CA, USA) in chloroform (CHCl₃) and the analysis parameters were as follows: mobile phase flow 1 mL/min; column temperature 30 °C, used column: PLgel 5 μm MIXED-C (300 × 7.5 mm). Aliphatic alcohols for depolymerization (methanol 99%, ethanol 99%) were supplied by Honeywell Research Chemicals, Charlotte, NC, USA (used alcohols were not claimed either synthetic or bio-source by the supplier). The catalyst for alcoholyses (p-toluensulphonic acid monohydrate), methacrylic anhydride (94%), potassium hydroxide (p.a.), d-chloroform (CDCl₃; 99.8%), and 2-ethylhexanoic acid (for synthesis) were all acquired from Sigma-Aldrich, Prague, Czech Republic.

Zinc and manganese ferrites (Zn_0.5Fe_2.5O₄ and Mn_0.5Fe_2.5O₄) were synthesized by FSP.^{27 (link)} Liquid precursor solutions were prepared by dissolving
iron(III) nitrate nonahydrate (purity 98%; Sigma-Aldrich, Sweden)
and either zinc nitrate hexahydrate (purity 98%; Sigma-Aldrich) or
manganese(II) nitrate tetrahydrate (purity 97%; Sigma-Aldrich) in
a solvent mixture (1:1) of 2-ethylhexanoic acid (99%; Sigma-Aldrich)
and ethanol (>99.7%, HPLC grade; VWR, Belgium) to obtain a total
metal
concentration of 0.7 M. Reference pure iron oxide (γ-Fe₂O₃) was produced from a 0.7 M iron(III) nitrate
nonahydrate precursor solution.
The precursor solutions were
stirred for at least 1 h at room temperature. Subsequently, the precursor
was fed at 6 mL min^–1 and dispersed using 3 L min^–1 O₂ (>99.5%, Linde AGA Gas AB, Sweden)
at a constant pressure (1.6 bar). The flame was ignited by a premixed
supporting flame of CH₄ and O₂ (>99.5%, Linde
AGA Gas AB) at flow rates of 1.5 and 3.2 L min^–1, respectively. A 5 L min^–1 O₂ sheath
gas was fed through the outermost sinter metal plate of the FSP burner.
Gas flow rates were controlled with calibrated mass flow controllers
(Bronkhorst, the Netherlands). The particles were collected on a glass
fiber filter (Albert LabScience, Germany) with the aid of a Mink MM
1144 BV vacuum pump (Busch, Sweden).