Effects of the structure and morphology of zinc glutarate on the fixation of carbon dioxide into polymer

Multinuclear Zinc-Magnesium Hydroxide Carboxylates: A Predesigned Model System for Copolymerization of CO2 with Epoxides

Among numerous catalysts in the ring-opening copolymerization of epoxides with carbon dioxide (CO2), zinc dicarboxylate complexes are the most common type, and in the family of metal-based homogeneous catalysts, zinc and magnesium complexes have attracted widespread attention. We report on the synthesis and structural characterization of a zinc-magnesium benzoate framework templated by the central hydroxide anion with μ3-κ2:κ2:κ2 coordination mode, [ZnMg2(μ3-OH)(O2CPh)5]n (n = 1 or 2). The resulting heterometallic system forms stable Lewis acid-base adducts with tetrahydrofuran (THF) and cyclohexene oxide (CHO), which crystallize as the hexanuclear zinc-magnesium hydroxide carboxylate cluster [ZnMg2(μ3-OH)(O2CPh)5(L)2]2 (L = THF or CHO). Their X-ray crystal structure analysis revealed that the Zn center prefers 4-fold coordination and the Mg centers demonstrated the ability to accommodate higher coordination numbers, and as a result, the heterocyclic molecules are exclusively bonded to 6-fold Mg atoms. The heteronuclear carboxylate aggregates appeared active in the copolymerization reaction at elevated temperatures to produce an alternating poly(cyclohexene carbonate).

Surface activated zinc-glutarate for the copolymerization of CO2 and epoxides

A sustainable CO2 polymerization using surface activated zinc glutarate catalysts produces industrially useful polymers with good catalytic activity.

Zn(ii)@TFP-DAQ COF: an efficient mesoporous catalyst for the synthesis of N-methylated amine and carbamate through chemical fixation of CO2

Selective N-methylation and carbamate formation reactions were demonstrated via the chemical incorporation of CO₂ using a Zn-loaded TFP-DAQ COF (covalent organic framework) as an active catalyst under mild reaction conditions.

Triethyl borane-regulated selective production of polycarbonates and cyclic carbonates for the coupling reaction of CO2 with epoxides

The copolymerization of CO₂ and epoxides bearing phenyl group is achieved by the combination of Lewis bases and excess triethyl borane that decides the selectivity.

Study on Thermal Decomposition Behaviors of Terpolymers of Carbon Dioxide, Propylene Oxide, and Cyclohexene Oxide

The terpolymerization of carbon dioxide (CO₂), propylene oxide (PO), and cyclohexene oxide (CHO) were performed by both random polymerization and block polymerization to synthesize the random poly (propylene cyclohexene carbonate) (PPCHC), di-block polymers of poly (propylene carbonate–cyclohexyl carbonate) (PPC-PCHC), and tri-block polymers of poly (cyclohexyl carbonate–propylene carbonate–cyclohexyl carbonate) (PCHC-PPC-PCHC). The kinetics of the thermal degradation of the terpolymers was investigated by the multiple heating rate method (Kissinger-Akahira-Sunose (KAS) method), the single heating rate method (Coats-Redfern method), and the Isoconversional kinetic analysis method proposed by Vyazovkin with the data from thermogravimetric analysis under dynamic conditions. The values of ln k vs. T⁻¹ for the thermal decomposition of four polymers demonstrate the thermal stability of PPC and PPC-PCHC are poorer than PPCHC and PCHC-PPC-PCHC. In addition, for PPCHC and PCHC-PPC-PCHC, there is an intersection between the two rate constant lines, which means that, for thermal stability of PPCHC, it is more stable than PCHC-PPC-PCHC at the temperature less than 309 °C and less stable when the decomposed temperature is more than 309 °C. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric analysis/infrared spectrometry (TG/FTIR) techniques were applied to investigate the thermal degradation behavior of the polymers. The results showed that unzipping was the main degradation mechanism of all polymers so the final pyrolysates were cyclic propylene carbonate and cyclic cyclohexene carbonate. For the block copolymers, the main chain scission reaction first occurs at PC-PC linkages initiating an unzipping reaction of PPC chain and then, at CHC–CHC linkages, initiating an unzipping reaction of the PCHC chain. That is why the T_−5% of di-block and tri-block polymers were not much higher than that of PPC while two maximum decomposition temperatures were observed for both the block copolymer and the second one were much higher than that of PPC. For PPCHC, the random arranged bulky cyclohexane groups in the polymer chain can effectively suppress the backbiting process and retard the unzipping reaction. Thus, it exhibited much higher T_−5% than that of PPC and block copolymers.

Enhanced Properties of Biodegradable Poly(Propylene Carbonate)/Polyvinyl Formal Blends by Melting Compounding

Polyvinyl formal (PVF) was first synthesized via the reaction of poly(vinyl alcohol) (PVA) and formaldehyde. The synthesized PVF exhibits a high decomposition temperature, glass transition temperature, and low melting point compared to pristine PVA. The synthesized PVF can be melt processed at temperatures much lower than PVA. Poly(propylene carbonate) (PPC) and the as-made PVF were melt blended in a Haake mixer. The mechanical properties, thermal behaviors, and morphologies of PPC/PVF blends were investigated. Compared to the pure PPC, PPC/PVF blends show higher tensile strength and Vicat softening temperature. Thermogravimetric (TGA) result reveals that the thermal stabilities of PPC/PVF blends decreased with the increase of the content of PVF. Scanning electron microscopy (SEM) observation indicates that the interfacial compatibility of the PVF and PPC matrix is better than that of the PVA and PPC matrix. The PPC/PVF blends show much better comprehensive properties compared to pure commercial PPC, which provides a practical way to extend the application of PPC copolymer.

Multiblock copolymers of PPC with oligomeric PBS: with low brittle–toughness transition temperature

In order to decrease the brittle–toughness transition temperature and increase the mechanical strength of poly(propylene carbonate) (PPC), a series of multiblock copolymers of poly(propylene carbonate)-multiblock-poly(butylene succinate) (PPC-mb-PBS) are designed and synthesized. ¹H-NMR, DOSY and GPC results demonstrate the successful synthesis of PPC-mb-PBSs with designed multiblock sequence. The thermal, crystalline and mechanical properties of these PPC-mb-PBSs are evaluated by DSC, TGA, POM, tensile and tearing testing. Experiment results demonstrate that crystallinity, thermal and mechanical properties of PPC-mb-PBSs can be readily modulated by changing the composition and block length of PPC and PBS moieties. It is found that all the prepared PPC-mb-PBSs are semi-crystalline polymers with a melting temperature at 93–109 °C and a T_g at around −40 °C. Both crystallization rate and crystallinity of the multiblock copolymers increase with increasing both PBS content and PBS block length. As a consequent, the tensile strength increases with increasing PBS/PPC block ratios at room and lower temperatures. In conclusion, the amorphous PBS phase in the block copolymers acts as soft segment, endowing PPC-mb-PBS copolymers with much better flexibility than PPC at low temperature of 273 K when PPC segments are frozen.

In present work, biodegradable multiblock copolymers from oligomeric PPC and PBS with low brittle–toughness transition temperature and superior mechanical properties was synthesized, making it more potential candidate as packaging materials.

Synthesis of Aliphatic Carbonate Macrodiols and Their Application as Sustainable Feedstock for Polyurethane

High-molecular-weight poly(propylene carbonate) (PPC) [number-average molecular mass (M _n): 80 000-100 000] is readily alcoholized into PPC macrodiols in the presence of 1,2-propanediol (PDO), 1,4-butanediol (BDO), or 1,6-hexanediol (HDO). The high-molecular-weight PPC and small amount of diols, such as PDO, BDO, or HDO, were stirred at elevated temperatures to convert the extremely viscous high-molecular-weight polymer to low-molecular-weight macrodiols with gel permeation chromatography-measured M _n of about 3000 Da. The chopping reaction of the high-molecular-weight PPC was studied in detail, such as the influences of the catalyst residue, the kinds of alcoholysis agents, reaction temperature, and time. The reaction mechanism of alcoholysis is proposed according to the experimental results. The results indicate that the presence of a trace residue of zinc catalyst (Zn-G-III) in PPC, excess diol feeding, and higher temperature can accelerate the alcoholysis. Moreover, different diols can produce different PPC macrodiols with varying end-capping. Finally, polycarbonate ether urethane can be successfully synthesized using as-synthesized PPC macrodiols and poly(propylene glycol) (M _n ≈ 3000) as the soft segment and 4,4'-diphenylmethane diisocyanate or BDO as the hard segment. The full evaluation for the synthesized PPC macrodiols demonstrates their potential applications in the polyurethane industry.

Zinc glutarate-mediated copolymerization of CO2 and PO – parameter studies using design of experiments

Parameter studies of the PO/CO₂-copolymerization revealed the importance of the surface coverage of a nanoscopic ZnGA catalyst.

A Novel Single-Ion-Conducting Polymer Electrolyte Derived from CO2-Based Multifunctional Polycarbonate

This work demonstrates the facile and efficient synthesis of a novel environmentally friendly CO₂-based multifunctional polycarbonate single-ion-conducting polymer electrolyte with good electrochemistry performance. The terpolymerizations of CO₂, propylene epoxide (PO), and allyl glycidyl ether (AGE) catalyzed by zinc glutarate (ZnGA) were performed to generate poly(propylene carbonate allyl glycidyl ether) (PPCAGE) with various alkene groups contents which can undergo clickable reaction. The obtained terpolymers exhibit an alternating polycarbonate structure confirmed by ¹H NMR spectra and an amorphous microstructure with glass transition temperatures (T_g) lower than 11.0 °C evidenced by differential scanning calorimetry analysis. The terpolymers were further functionalized with 3-mercaptopropionic acid via efficient thiol-ene click reaction, followed by reacting with lithium hydroxide, to afford single-ion-conducting polymer electrolytes with different lithium contents. The all-solid-state polymer electrolyte with the 41.0 mol % lithium containing moiety shows a high ionic conductivity of 1.61 × 10^-4 S/cm at 80 °C and a high lithium ion transference number of 0.86. It also exhibits electrochemical stability up to 4.3 V vs Li⁺/Li. This work provides an interesting design way to synthesize an all-solid-state electrolyte used for different lithium batteries.

A novel biodegradable polymeric surfactant synthesized from carbon dioxide, maleic anhydride and propylene epoxide

Novel biodegradable polymeric surfactants were synthesized by the sulfonation of gradient structured terpolymers of CO₂, propylene epoxide and maleic anhydride.

Mechanism studies of terpolymerization of phthalic anhydride, propylene epoxide, and carbon dioxide catalyzed by ZnGA

Monomer reactivity ratios of CO₂ and phthalic anhydride (PA) are evaluated and a mechanism is discussed for ZnGA catalyzed PA/CO₂/PO terpolymerizations.