1 4 butanediol

2,5-furan dicarboxylic acid (purum 97%) tetrabutyltitanate (TBT) catalyst of analytical grade and 1,4-Butanediol of analytical grade used in polyester synthesis, were purchased from Sigma-Aldrich Chemical Co. (Chemie GmbH, Steinheim, Germany). All other materials and solvents used were of analytical grade.
High molecular weight poly(ethylene 2,5-furandicarboxylate) (PEF), poly(propylene 2,5-furandicarboxylate) (PPF), poly(butylene 2,5-furandicarboxylate) (PBF) and poly(1,4-cyclohexanedimethlene 2,5-furandicarboxylate) were synthesized by applying melt polycondensation following the general procedure shown in Scheme 1 and described in detail in our previous studies [16 (link),19 (link),32 (link),60 (link)]. Solid-state polycondensation (SSP) was subsequently applied to produce polymers of high molecular weight at 220 °C and 170 °C for PEF and PPF, respectively, for 8 h. PET, PPT, PBT and PBN were also prepared, as described in our previous studies, by melt polycondensation procedure [39 (link),40 (link)]. PLA with average molecular weight Mn = 20,000 Da and polydispersity index about 1.3 and poly(bisphenol A carbonate) with average Mw about 45,000 were purchased from Sigma Aldrich Chemical Co.

Butyl glycidyl ether (BGE, Mw: 130.19, 95%), diethanolamine (DEA, Mw: 105.14, 99%), poly(tetramethylene ether)glycol (Mw: 1,000, 99%) (PTMEG1000), and 1,4-butanediol (BDO; 99%) were obtained from Sigma–Aldrich. Vanillyl alcohol (VA, Mw: 154.17, 98%) was purchased from Tokyo Chemical Industry in Korea. 4,4’-methylene diphenyl diisocyanate (MDI, 99%) was obtained from BASF (BASF Korea, Yeosu, Korea).

1,4-Butanediol (BD, 99%), poly(propylene oxide) (PPO, average M_n ~1000), deuterated chloroform (CDCl₃-d, 99 atom% D), titanium(IV) tert-butoxide (Ti(OBu)₄, 97%), poly(methyl methacrylate) standards with molecular weights between 4250 and 273,000 sodium phosphate dibasic (≥99%), sodium phosphate monobasic (≥99%) and Porcine pancreas lipase (Type II, 100-500 units/mg protein) were purchased from Sigma-Aldrich Chemicals Co. 2,5-Furandicarboxylic acid (FDCA, >98%) was purchased from TCI Europe NV. Concentrated hydrochloric acid (37%) was purchased from Panreac; and methanol and chloroform (pro-analysis and HPLC grade) were purchased from Fisher Scientific. All chemicals were used as received, without further purification.

PU was synthesized by bulk polymerization (see, Figure 1) according to previously described method using polytetramethylene ether glycol (PTMEG-650), 1,4-butanediol (BDO) and methylene diphenyl di-isocyanate (MDI) (raw materials purchased from Sigma Aldrich, St. Louis, MO, USA) [31 (link)]. The molar ratio of MDI, 1,4-butanediol and PTMEG was set to 1.5:0.5:1 and the content of soft chain segment and hard segment were 61% and 39%, respectively. Briefly, synthesis was carried out in a 500 mL round bottomed four necked flask equipped with a mechanical stirrer, thermometer and condenser. First, dehydration process of PTMEG for 2 h under reduced pressure at 90 °C was performed. Second, MDI and PTMEG were mixed and then stirred continuously for 1.5 h. Third, BDO was added and the reaction allowed to continue for 30 min. After the reaction, polymer was poured out into a Teflon plate and cured at 80 °C for 12 h inside a vacuum oven. Finally, the polymeric mould was crushed and pelletized using a single screw extruder.

DHBA (3,4-Dihydroxybenzoic acid), 1,1′-carbonyldiimidazole (CDI), thionyl chloride (SOCl₂), triethyl orthoformate (TEOF), resin Amberlyst 15, polycaprolactone diol with molecular weight of 2037 (PCL-2000), 1,4-butanediol (BD), ε-caprolactone (ε-CL), tin(II) 2-ethylhexanoate (Sn(Oct)₂), N,N-dimethyl-acetamide (DMAc), and 1,6-diisocyanatohexane (HDI) were purchased from Sigma-Aldrich (Madrid, Spain). The diisocyanate product was freshly distilled at low pressure before use, and the rest of the products were used as received. AMPD (2-Amino-2-methyl-1,3-propanediol) and N,N-diethanolamine (DEA) were purchased from Merck (Madrid, Spain) and used as received.

Sodium hydride (NaH, 60% dispersion in mineral oil), 2-methyl-1,3-propanediol (99%), 2,2-dimethyl-1,3-propanediol (99%), 1,3-propanediol (99%), 2,2-diethyl-1,3-propanediol (99%), 2,2,4-trimethyl-1,3-pentanediol (97%), (±)-1,3-butanediol (99.5%), 3-methyl-1,3-butanediol (97%), ethylene glycol (anhydrous, 99.8%) and 1,4-butanediol (99%) were purchased from Sigma-Aldrich. Diethyl carbonate (DEC, 99%) was purchased from Alfa Aesar. All chemicals were used as received.