Propylene glycol

Oleic acid tech. 90.0% (Alfa Aesar, Ward Hill, MA, USA), propylene glycol pure p.a. (Chempur, Piekary Śląskie, Poland), succinic acid ≥ 99.5% (Pol-Aura, Zabrze, Poland), toluene pure p.a. (Chempur, Piekary Śląskie, Poland), and methanesulfonic acid > 99.0% (TCI, Zwijndrecht, Belgium), were used in this study to synthesize mixed esters. Formic acid 85.0% (Chempur, Piekary Śląskie, Poland), hydrogen peroxide 30.0% (Chempur, Piekary Śląskie, Poland), and di-sodium hydrogen phosphate dihydrate pure p.a. (Chempur, Piekary Śląskie, Poland) were used for epoxidation reaction and purification of epoxidized mixed esters.
Suspension PVC with a K value of 70 and a bulk density of 0.495 g/cm³ (Polanvil S-70, Anwil S.A., Włocławek, Poland) was used in this study. Calcium carbonate filler (Extra 1, Piotrowice II, Tarnobrzeg, Poland) and Ca/Zn thermal stabilizer (Baeropan R8890KA/2, Baerlocher GmbH, Unterschleißheim, Germany) were used as additives. PVC blends were plasticized with commercially available plasticizers, i.e., DINP (Jayflex, ExxonMobil, Machelen, Belgium), DEHP (Oxoplast O30, Grupa Azoty ZAK S.A., Kędzierzyn-Koźle, Poland), and with plasticizers synthesized (Samples 1, 2, 3, and 4) in this work.

Chitosan produced from Aspergillus niger (Deacetylation degree (DD) = 92%, determined by FT-IR method; Mw = 890,000 g/mol; and 100–300 cps), fluorescein, L-aspartic, and L-glutamic acid were purchased from PolAura, Dywity, Poland. Propylene glycol, isopropanol, methanol (HPLC grade), (CH₃COO)₂Zn∙2H₂O, CaCl₂·2H₂O, MgSO₄, KCl, KOH, ethanol (96%, 99.9%), KHPO₄, Na₂HPO₄, NaHCO₃, NaCl, HCl, NaOH, mouse L929 (commercial cell line from mouse C3H/An connective tissue for research purpose only, The European Collection of Authenticated Cell Cultures (ECACC)), Dulbecco’s Modified Eagle Medium (DMEM) with glucose content cell culture medium, antibiotics (streptomycin/penicillin), fetal bovine serum (FBS), phosphate buffer solution (PBS), trypsin with EDTA, and Triton-X-100 were purchased from Sigma Aldrich, Poznań, Poland. For the study, pure cannabidiol of HPLC confirmed purity was used, purchased from Dobre Konopie, Mysłowice, Poland.