Preparation of macrodiols and polyols by chopping high‐molecular‐weight aliphatic polycarbonates

Abstract

High-molecular-weight poly(1,4-butylene carbonate) (PBC) (M n : 40,000290,000) was prepared through the condensation polymerization of dimethyl carbonate (DMC) and 1,4butanediol (BD) in the presence of 0.05 mol % sodium alkoxide catalyst. The subsequent feeding of 15 mol % HOAOH, such as 1,6-hexanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, or 1,4-benzenedimethanol and stirring at 190-150 C converted the extremely thick high-molecular-weight polymer to lowmolecular-weight macrodiols with GPC-measured M n $2000. The analysis of the 1 H NMR spectra indicated that the -A-units and 1,4-butylene units were randomly distributed in the resulting oligomers. The chopping of the high-molecular-weight PBC using either triols or tetraols such as glycerol propoxylate, 1,1,1-tris(hydroxymethyl)ethane, or pentaerythritol also afforded macropolyols containing branched chains with GPCmeasured M n $2000. When the chopped polymers were genuine PBCs, the resulting macrodiols or polyols were in a waxy state at room temperature. However, permanently oily compounds were obtained when the chopped polymers were prepared using 0.90 mole fraction of BD admixed with various other diols. The macrodiols and polyols synthesized in this study may have potential applications in the polyurethane industry.

Chopping high‐molecular weight poly(1,4‐butylene carbonate‐co‐aromatic ester)s for macropolyol synthesis

“…The wax‐like materials showed melting temperatures ( T m ) around 45 °C [close to the T m of PBC (60 °C)], along with glass transition temperatures ( T g ) in the range of −44 to −22 °C in DSC scans [Figure (a)], whereas there was no T m signal for the oily samples [Figure (b)]. The T g of a macropolyol that did not contain aromatic ester units, i.e., a sample prepared by chopping PBC with 1 , was −49 °C . By increasing the amounts of terephthalate units to 10, 20, and 30 mol %, the T g value gradually increased to −44, −39, and −35 °C, respectively (entries 5, 6, and 2 in Table ).…”

“…Aliphatic polycarbonate‐based macropolyols are attractive due to their hydrolytic stability and resistance to sunlight and oxidative degradation . Recently, we reported the syntheses of macropolyols with unique chain compositions by chopping high‐molecular weight poly(1,4‐butylene carbonate)s (PBC) with a diol or polyol . In this paper, we report the preparation of a further type of macropolyol by the chopping of high‐molecular weight poly(1,4‐butylene carbonate‐ co ‐aromatic ester)s. Aromatic ester units were incorporated into these macropolyols through the use of dimethyl terephthalate, dimethyl isophthalate, or dimethyl phthalate in the initial condensation reaction, which are inexpensive chemicals used on a large scale in the polymer industry.…”

Branched poly(1,4-butylene carbonate-co-terephthalate)s: LDPE-like semicrystalline thermoplastics

“…When a small amount of trifunctional glycerol propoxylate ( 1 in Chart ) additive was fed into the BD/DMC/DMT polycondensation, branched PBCTs were generated. Glycerol could not be used as a trifunctional branching agent, because it formed thermodynamically stable five‐membered cyclic carbonate end‐groups . When the polycondensation was carried out at a [DMT]/[BD] feed ratio of 0.40 with an additional feed of a small amount of trifunctional 1 ([ 1 ]/[BD] feed ratio, 0.20–0.50 mol %), high‐molecular weight PBCTs ( M w , 180k–200k) were generated without gel formation (Table , entries 2–5).…”

“…Therefore, poly(1,4‐butylene carbonate) (PBC), which is synthesized by polycondensation of DMC and BD, has been suggested as new class of sustainable polymers that are biodegradable . Although there have been noticeable advances in making high‐molecular weight PBC, its melting temperature ( T m ) is inappropriately low (60 °C) to be used as commodity thermoplastics . The T m s of the aforementioned compostable aliphatic polyesters available on the market are higher than 100 °C (PHA, 153 °C; PLA, 152 °C; PBS, 115 °C; and PBAT, 125 °C), targeting the comparable thermal properties similar to those of PE or PP.…”

Efficient synthesis of organic carbonates and poly(1,4‐butylene carbonate‐co‐terephthalate)s

“…Currently, DMC is recognized as a green, abundant, and inexpensive chemical because of its production from CO 2 or CO . We reported the synthesis of potentially biodegradable poly(1,4‐butylene carbonate) (PBC) and poly(1,4‐butylene carbonate‐ co ‐terephthalate)s (PBCTs) using DMC as the monomer [Scheme (b)] …”