Sustainable Polycarbonates from a Citric Acid-Based Rigid Diol and Recycled BPA-PC: From Synthesis to Properties

Abstract

Here we present a series of homopolycarbonates (homo-PCs) and copolycarbonates (co-PCs) based on a novel bicyclic diol octahydro-2,5-pentalenediol (OPD) from naturally occurring citric acid and bis­(hydroxyethyl ether) of bisphenol A (BHEEB), synthesized by melt polycondensation. The recently developed OPD has been shown to be a highly rigid and thermally stable building block suitable for the construction of performance polymers. BHEEB, which was obtained from the chemical recycling of BPA-PC, was used to compensate for the low reactivity of OPD and to modify the brittleness of polycarbonate (PC) solely based on OPD, without compromising other properties. The single crystal of the endo-endo isomer of OPD was deliberately obtained, and its absolute stereochemistry was unambiguously identified by single-crystal X-ray diffraction for the first time. The polymers had M n in the 10 100–20 000 g mol–1 range and gradually decreased with increasing OPD content. NMR analyses revealed the random structures of the co-PCs and the molar content of OPD in all cases were lower than its corresponding feeds. Interestingly, in contrast with the semicrystalline poly­(octahydro-2,5-pentalenediol carbonate) (abbreviated as pre-POC) prepared in a different protocol in our previous article, poly­(octahydro-2,5-pentalenediol carbonate) (abbreviated as POC) in this study exhibited amorphous feature with a lower T g of 74.5 °C. A “ductile–to–brittle” transition occurred with increasing OPD content in the PBC chains, which can be ascribed to their low molecular weights and the low entangled strand density due to the rather stiff polymer chains. This work combines chemical recycling and the biobased polymer together, which would bring a feasible way to satisfy the demands of sustainability.

Tailoring the Performance of Vegetable Oil-Based Waterborne Polyurethanes through Incorporation of Rigid Cyclic Rings into Soft Polymer Networks

“…The signals at around δ 4.5, δ 4.33, and δ 3.96 ppm can be assigned to the protons, numbered as 3, 7, and 10, on carbons that were linked to hydroxyl groups in isomer A′ and A, respectively, while the protons (numbered as 1 and 5) on bridged carbons exhibited overlapped multiplets at around 2.39 and 2.21 ppm, respectively . The integral area ratio of proton peaks 3 to 7, 3 to 10, and 1 to 5 are 6.1:1, 5.6:1, and 3.2:1, respectively, implying that the molar ratio of A to A′ is around 3:1 . In the FTIR spectra of OPD, an identical strong absorption band at 3295 cm –1 can be observed, corresponding to the typical −OH stretching vibration on the bicycles.…”

“…In this work, octahydro-2,5-pentalenediol (OPD) was synthesized from dimethyl-1,3-acetonedicarboxylate (derived from naturally occurring citric acid) and glyoxal through Weiss–Cook condensation, decarboxylation under acidic conditions and reduction with NaBH 4 . OPD, with two fused cyclopentane rings, exhibits excellent rigidity and thermal stability, which envisioned to greatly restrict the motion of the polymer chain if incorporated in the macromolecular structures, leading to the high performance of polymers (high T g and tensile strength). − …”

Development of High-Molecular-Weight Fully Renewable Biopolyesters Based on Oxabicyclic Diacid and 2,5-Furandicarboxylic Acid: Promising as Packaging and Medical Materials

“…In contrast, PEOB and PTOB synthesized from diacid in this work had higher T g values than the room temperature; thus, they were brittle. This phenomenon can be ascribed to the low density of the entangled strand caused by the rather rigid OBDA moiety predisposing the glassy polyester to form a weak crack upon stretching. , With the increasing number of methylene group sequences in the diol moiety, the mobility of the polyester chain segments was enhanced, and a “brittle-to-ductile” transition occurred for PBOB, with a moderate tensile toughness (ε m ∼ 85%) (Figure S7). In addition, high-molecular-weight PBOB displayed a satisfactory tensile strength (σ b ) of 12 MPa, comparable to that of low-density polyethylene (LDPE), due to the rigid OBDA units.…”

“…Aliphatic bio-based polyesters possess advantages such as desirable biodegradability, reduced toxicity, and general biocompatibility. However, poor thermal stability and mechanical strength are common defects in these polyesters, especially for amorphous aliphatic polyesters. ,,− The incorporation of aromatic building blocks is an appealing strategy to address this limitation, ,, FDCA has emerged as a new alternative bio-based aromatic diacid to petroleum-derived terephthalic acid and has been selected by the U.S. Department of Energy as one of the top 12 value-added biomass-derived chemicals. The FDCA-based polyesters poly (ethylene 2,5-furandicarboxylate) (PEF), poly­(propylene 2,5-furandicarboxylate) (PPF), and poly­(butylene 2,5-furandicarboxylate) (PBF) are regarded as the green polyesters with the most potential value, having high thermal stability, tensile strength, and gas barrier properties .…”

Rigid biobased polycarbonates with good processability based on a spirocyclic diol derived from citric acid

“…Gao, et al have recently reported on octahydro-2,5-pentalenediol (OPD, Scheme 1), derived from citric acid. 19,20 Just like isosorbide, it has a rigid V-shaped structure, but instead of furan rings it has two cisfused carbocycles. This alicyclic diol yielded PCs with good thermal stability (thermal decomposition at 276°C) and T g s up to 80°C, demonstrating that the mimicking of the isosorbide bicyclic structure is an efficient approach to increase the chain rigidity of polymers.…”