Copolycarbonates Based on a Bicyclic Diol Derived from Citric Acid and Flexible 1,4-Cyclohexanedimethanol: From Synthesis to Properties

We investigate the scope of the organocatalyzed step-growth copolymerization of CO 2 -sourced exovinylene bicyclic carbonates with bio-based diols into polycarbonates. A series of regioregular poly(oxo-carbonate)s were prepared from sugar-(1,4butanediol and isosorbide) or lignin-derived (1,4-benzenedimethanol and 1,4-cyclohexanediol) diols at 25 °C with 1,8diazabicyclo[5.4.0]undec-7-ene (DBU) as a catalyst, and their defect-free structure was confirmed by nuclear magnetic resonance spectroscopy studies. Their characterization by differential scanning calorimetry and wide-angle X-ray scattering showed that most of them were able to crystallize. When the polymerizations were carried out at 80 °C, some structural defects were introduced within the polycarbonate chains, which limited the polymer molar mass. Model reactions were carried out to understand the influence of the structure of alcohols, the temperature (25 or 80 °C), and the use of DBU on the rate of alcoholysis of the carbonate and on the product/linkage selectivity. A full mechanistic understanding was given by means of static-and dynamic-based density functional theory (DFT) calculations showing the determining role of DBU in the stability of intermediates, and its important role in the rate-determining steps is revealed. Furthermore, the origin of side reactions observed at 80 °C was discussed and rationalized by DFT modeling. As impressive diversified bio-based diols are accessible on a large scale and at low cost, this process of valorization of carbon dioxide gives new perspectives on the sustainable production of bioplastics under mild conditions.

Section: Introductionmentioning

confidence: 80%

Access to Biorenewable and CO₂-Based Polycarbonates from Exovinylene Cyclic Carbonates

Siragusa

Broeck

Ocando

et al. 2021

“…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). − …”

Section: Introductionmentioning

confidence: 99%

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

Liang

Yan-chun

Huang

et al. 2019

Vegetable oil-based polymeric materials always suffer from relatively poor performance, such as lower tensile strength and glass transition temperatures, than petroleum-based polymeric materials, which greatly limit their practical applications. In this study, octahydro-2,5-pentalenediol (OPD) was synthesized from naturally occurring citric acid and used together with castor oil as the polyol blends for the production of bio-based waterborne polyurethane (PU) dispersions (PUDs). The effects of the OPD contents on the particle size and ζ potential of the resulting polyurethane dispersion, and the thermal stability, mechanical properties, and hydrophilicity of the resulting polyurethane films were systematically investigated. Taking advantage of the rigid cyclic structures of the OPD and the flexible fatty acid chain of castor oil, waterborne polyurethane (WPU) films with tailorable mechanical performance ranging from elastomeric polymers to rigid plastics were successfully prepared and characterized. The tensile strength of the samples increases from 9.5 to 22.3 MPa with the ratio between OPD and castor oil increasing from 0:10 to 5:5, whereas their elongation at break decreases from 192 to 12%. A significant increase in the glass transition temperature, transparency, and anticorrosive properties was observed for the resulting polyurethane films with increasing the OPD content. However, the thermal stability of the PU films exhibited a slight decrease as the OPD content increased. Moreover, the water contact angle exhibited a slight increase for the polyurethane films prepared from polyol blends compared to the WPU film prepared from pure castor oil. This work provides a novel route to tailor the performance of vegetable oil-based waterborne polyurethanes through the incorporation of rigid cyclic rings into soft polymer networks.

“…In contrast, higher T 5% and T d values were observed for PTS, which are 352 and 399 °C, respectively, demonstrating the higher thermal stability compared to that of PBS. For both series, the incorporation of TCDM resulted in an initial rise followed by a fall in the T 5% values, which can be ascribed to the converse effects of the increasing Φ T and the decreasing M n (Table ), because the thermostability of polymers is also influenced by the polymer chain length …”

Section: Resultsmentioning

confidence: 93%

“…For both series, the incorporation of TCDM resulted in an initial rise followed by a fall in the T 5% values, which can be ascribed to the converse effects of the increasing Φ T and the decreasing M n (Table 2), because the thermostability of polymers is also influenced by the polymer chain length. 37 The thermal behaviors of these PBS copolyesters are systematically investigated using DSC (Figure S5); the parameters measured are given in Table 3, and the thermal transition data are comparatively plotted in Figure 5. The incorporation of TCDM in the backbone of PBS, regardless of the synthetic methods, steadily increased the T g values.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Random and Multiblock PBS Copolyesters Based on a Rigid Diol Derived from Naturally Occurring Camphor: Influence of Chemical Microstructure on Thermal and Mechanical Properties

Jiang

Guan

et al. 2020

Self Cite

(1R,3S)-1,2,2-trimethylcyclopentane-1,3-dimethanol (TCDM) is a rigid alicyclic diol prepared by oxidation and subsequent reduction of naturally occurring camphor. To improve the low glass transition temperature (T g), slow degradation rate, and brittleness of poly(butylene succinate) (PBS), two series of PBS copolyesters based on TCDM were synthesized using two different methods. Random copolymerization (RC) of a mixture of TCDM, 1,4-butanediol (BDO), and 1,4-succinic acid (SA) afforded random PBS copolyesters, while reactive blending (RB) of pure PBS and PTS (homopolyester based on TCDM and SA) afforded PBS copolyesters with blocklike chemical microstructures. For both series, the insertion of TCDM units resulted in elevated thermal stability and higher T g values compared to those of neat PBS. The RB-prepared copolyesters displayed higher melting points, a higher degree of crystallinity, and higher mechanical properties with respect to those of their random counterparts obtained by RC. The incorporation of TCDM units enhanced the hydrolytic degradation rates for both series, which is more pronounced for the RC-prepared copolyesters. Overall, this work confirmed the effectiveness of the RB technology in preparing high-performance biopolymers such as improving the sustainability of raw materials, achieving high T g values, and promoting the mechanical strength and biodegradability as well.