Ring-opening Copolymerization Research Articles

Synthesis and Solvent Free DLP 3D Printing of Degradable Poly(Allyl Glycidyl Ether Succinate)

AbstractDigital light processing (DLP) printing forms solid constructs from fluidic resins by photochemically crosslinking polymeric resins with reactive functional groups. DLP is used widely due to its efficient, high‐resolution printing, but its use and translational potential has been limited in some applications as state‐of‐the‐art resins experience unpredictable and anisotropic part shrinkage due to the use of solvent needed to reduce resin viscosity and layer dependent crosslinking. Herein, poly(allyl glycidyl ether succinate) (PAGES), a low viscosity, degradable polyester, was synthesized by ring opening copolymerization and used in combination with degradable thiol crosslinkers to afford a solvent free resin that can be utilized in DLP printing. Varying resin formulations of PAGES polymer are shown to decrease part shrinkage from 14 % to 0.3 %. Photochemically printed parts fabricated from PAGES possess tensile moduli between 0.43 and 6.18 MPa and degradation profiles are shown to vary between 12 and 40 days under accelerated conditions based on degree of polymerization and crosslink ratio.

Aminophosphonium organocatalysts for the ring-opening copolymerisation of epoxide and cyclic anhydride.

The Kirsanov reaction has been used to synthesise air stable, efficient and selective bifunctional aminophosphonium catalysts for the alternating ring-opening copolymerisation of cyclohexene oxide and phthalic anhydride without the need for a co-initiator.

Synthesis and Characterization of Heterodinuclear Indium(III)/Sodium(I) Complexes Containing Benzotriazole-Derived Phenolate Ligands: Effective Catalysts for Ring-Opening Copolymerization of Carbon Dioxide with Epoxides.

This study reported for the first time the facile synthesis of a series of novel structurally well-characterized heterodinuclear indium(III)/sodium(I) dihalide complexes containing benzotriazole-based bis(amino-phenolate) derivatives. All heterobimetallic In(III)/Na(I) complexes were found to be active single-component catalysts for the copolymerization of carbon dioxide (CO2) with cyclohexene oxide (CHO). Noteworthily, In/Na chloro complex 1 has been shown to give high copolymerization selectivity possessing >99% carbonate repeated units for CO2-derived poly(cyclohexene carbonate) production and displayed a turnover number of >1400 under the optimized conditions. Apart from the CO2/CHO copolymerization, the same complex was capable of mediating the CO2-copolymerization of 4-vinyl-1,2-cyclohexene oxide or cyclopentene oxide to deliver the related CO2-based polycarbonates. To the best of our knowledge, complex 1 in this work appears to be the first example of In/Na halide complex-promoted CO2/epoxide copolymerization that enabled the generation of aliphatic polycarbonates with good productivity and high product selectivity.

Degradable N-Vinyl Copolymers through Radical Ring-Opening Polymerization of Cyclic Thionocarbamates.

A thiocarbonyl radical ring-opening polymerization approach was implemented with cyclic thionocarbamates to generate degradable copolymers with N-vinyl monomers. The rigid structures of cyclic N-substituted thionocarbamates have been revealed by X-ray crystallography and NMR spectroscopy. The corresponding copolymers show incorporation of the thiocarbamates within the carbon backbone of polyvinylpyrrolidone influenced by acyl substituents through radical ring-opening copolymerization. The phenyl-substituted cyclic thionocarbamate copolymerized with N-vinyl carbazole and N-vinyl caprolactam, while little to no incorporation occurred with tBu acrylate and styrene, respectively. Further, these copolymers can undergo hydrolytic degradation under mild conditions. A new family of cyclic thionocarbamates capable of radical ring-opening copolymerization with N-vinyl monomers has been established.

Self-assembled mixed nanomicelles based hydrogel for enhanced transdermal bioavailability of allopurinol in gout therapy: In vitro and In vivo evaluation

Allopurinol (ALP), a preferred first line medication for the treatment of gout and hyperuricemia, exhibits poor solubility, a short half-life, and undergoes the hepatic first-pass effect, thus resulting in low oral bioavailability. Additionally, ALP is associated with several adverse effects, including hypersensitivity reactions, gastrointestinal issues, and hepatotoxicity. Here, we developed methoxy poly (ethylene glycol)- poly(lactide) (mPEG-PLA)/D-tocopherol polyethylene glycol 1000 succinate (TPGS) mixed nanomicelles (MNs)-based hydrogel for transdermal delivery of ALP to enhance its bioavailability, In vivo safety, and efficacy for gout treatment. To this end, mPEG-PLA diblock copolymer was synthesized via ring-opening copolymerization and characterized using Fourier transform infrared spectroscopy (FTIR), SEM micrograph, proton nuclear magnetic resonance (1H NMR) and Differential scanning calorimetric thermograms (DSC) analysis. Self-assembled mixed nanomicelles were formulated by thin film dispersed technique. The optimized mixed nanomicelles were analyzed for their physicochemical properties and subjected to in vitro, ex vivo and in vivo investigations. The final formulation (ALP-loaded MNs) exhibited a size of 59.12 nm, an encapsulation efficiency (EE) of 87 %, a PDI of 0.053, and a zeta potential of −22.3 mV. In Vitro release kinetics of the ALP-loaded MNs exhibited a sustained and site-specific release profile (p < 0.001). As compared with the ALP based hydrogel, 32-fold higher permeation flux was noticed from ALP-MNs loaded hydrogel with argan oil (ALP-MNs-AO-HG). The in vivo skin irritation study showed that the ALP-MNs-HG was well-tolerated with minimal signs of edema or erythema. ALP-MNs-AO-HG notably enhanced ALP bioavailability with a 7.67 ± 0.01 fold higher AUC0−t, 4.8 ± 0.03 fold longer mean residence time, and a 6 ± 0.04 fold extension in half-life as compared to the oral drug suspension. These results indicate that ALP-MNs based transdermal hydrogels exhibit the potential to enhance therapeutic outcomes by increasing bioavailability and abating the adverse effects associated with oral administration.

Mononuclear phenoxy-imine Mg(II) compounds as catalysts for the ring-opening copolymerization of epoxides with CO2

The ring-opening copolymerization (ROCOP) of epoxides with CO2 is an efficient gateway for synthesizing sustainable aliphatic polycarbonates. The demand for the use of biocompatible metals for the copolymerization is an appealing research goal. The oxophilic Mg(II) has been employed as a metal center in homodinuclear and heterodinuclear catalyst frameworks. However, there is scarce literature involving mononuclear Mg(II) compounds. This work investigates the catalytic activity of two series of phenoxy-imine containing mononuclear Mg(II) compounds for the copolymerization studies of epoxides with CO2 in conjugation with cocatalyst tetraphenylphosphonium chloride (TPPCl). The two series of Mg(II) compounds differed from each other in the number of ancillary ligands attached to the Mg(II) center. The two epoxides employed for the study include cyclohexene oxide (CHO) and propylene oxide (PO). The catalytic activity of the disubstituted Mg(II) compounds was higher compared to monosubstituted compounds. In addition, the dependence of catalytic activity and percentage of carbonate linkage with the variation in the substituent of the phenolate core and imine side arm were studied. At 40 bar CO2 pressure and 80 °C, the catalyst exhibited carbonate linkage up to 97 % for ROCOP with cyclohexene oxide (CHO) with the percentage of the highest m-centered tetrad reaching up to 94 %. The mechanism for the ROCOP of CHO with CO2 is proposed based on kinetics studies and experimental data, which is further supported by density functional theory-based calculations.

Selective Copolymerization from Mixed Monomers of Phthalic Anhydride, Propylene Oxide and Lactide Using Nano-Sized Zinc Glutarate.

Selective polymerization with heterogeneous catalysts from mixed monomers remains a challenge in polymer synthesis. Herein, we describe that nano-sized zinc glutarate (ZnGA) can serve as a catalyst for the selective copolymerization of phthalic anhydride (PA), propylene oxide (PO) and lactide (LA). It was found that the ring-opening copolymerization (ROCOP) of PA with PO occurs firstly in the multicomponent polymerization. After the complete consumption of PA, the ring-opening polymerization (ROP) of LA turns into the formation of block polyester. In the process, the formation of zinc-alkoxide bonds on the surface of ZnGA accounts for the selective copolymerization from ROCOP to ROP. These results facilitate the understanding of the heterogeneous catalytic process and offer a new platform for selective polymerization from monomer mixtures.

Synthesis and Solvent Free DLP 3D Printing of Degradable Poly(Allyl Glycidyl Ether Succinate).

Digital light processing (DLP) printing forms solid constructs from fluidic resins by photochemically crosslinking polymeric resins with reactive functional groups. DLP is used widely due to its efficient, high-resolution printing, but its use and translational potential has been limited in some applications as state-of-the-art resins experience unpredictable and anisotropic part shrinkage due to the use of solvent needed to reduce resin viscosity and layer dependent crosslinking. Herein, poly(allyl glycidyl ether succinate) (PAGES), a low viscosity, degradable polyester, was synthesized by ring opening copolymerization and used in combination with degradable thiol crosslinkers to afford a solvent free resin that can be utilized in DLP printing. Varying resin formulations of PAGES polymer are shown to decrease part shrinkage from 14% to 0.3%. Photochemically printed parts fabricated from PAGES possess tensile moduli between 0.43 and 6.18 MPa and degradation profiles are shown to vary between 12 and 40 days under accelerated conditions based on degree of polymerization and crosslink ratio.

Vanadium-Containing Ionic Liquids Derived from Complexes of Modified Edta as Catalysts of Epoxy-Anhydride Ring-Opening Copolymerization.

A new type of vanadium-containing ionic liquids (ILs) was synthesized by cation exchange from barium salts of oxidovanadium(IV) complexes stabilized by edta and its congeners (dcta, oedta, and heedta) serving as pentadentate ligands. All starting barium salts and several magnesium and cesium salts, serving as models for the cation exchange, were structurally characterized by single-crystal XRD analysis. The synthesized ILs consisting of organic cations (Bu4N+, Bmim+, and Bu4P+) and complex anions ([VO(edta)]2-, [VO(dcta)]2-, [VO(oedta)]-, and [VO(heedta)]-) were characterized by analytical and spectroscopic methods including EPR spectroscopy and cyclic voltammetry. Then, ILs were tested as catalysts for the ring-opening copolymerization of epoxy resin with cyclic anhydride showing significant catalytic activity, which led to production of highly cross-linked glassy thermosets. A detailed isothermal DSC kinetic study was performed for the most promising IL showing that the progress of cross-linking can be successfully fitted by the Kamal-Sourour model. Based on the DSC and NIR results, the initiation mechanism of the cross-linking in the presence of vanadium-containing IL was suggested. IL had ability to activate a rapid hydrolysis of anhydride cycle and the formed carboxyl groups initiated a polyesterification. In parallel, the role of imidazolium cation of IL for the initiation of chain-growth anionic copolymerization is also discussed.

Chain Shuttle between Dual Sites of a Monomolecular Organocatalyst Enables Controlled Ring-Opening Copolymerization

Chain Shuttle between Dual Sites of a Monomolecular Organocatalyst Enables Controlled Ring-Opening Copolymerization

Synergic Catalysis: the Importance of Intermetallic Separation in Co(III)K(I) Catalysts for Ring Opening Copolymerizations.

Dinuclear polymerization catalysts can show high activity and control. Understanding how to design for synergy between the metals is important to improving catalytic performances. Three heterodinuclear Co(III)K(I) catalysts, featuring very similar coordination chemistries, are prepared with different intermetallic separations. The catalysts are compared for the ring-opening copolymerization (ROCOP) of propene oxide (PO) with CO2 or with phthalic anhydride (PA). The catalyst with a fixed, wide intermetallic separation, LwideCoK(OAc)2 (Co-K = 8.06 Å), shows very high activity for PO/PA ROCOP, but is inactive for PO/CO2 ROCOP. On the other hand, the catalyst with a fixed, narrow intermetallic separation, LshortCoK(OAc)2 (Co-K, 3.59 Å), shows high activity for PO/CO2 ROCOP, but is much less active for PO/PA ROCOP. A bicomponent catalyst system, comprising a monometallic complex LmonoCoOAc used with an equivalent of KOAc[18-crown-6], shows high activity for both PO/CO2 and PO/PA ROCOP, provided the catalyst concentration is sufficiently high, but underperforms at low catalyst loadings. It is proposed that the two lead catalysts, LwideCoK(OAc)2 and LshortCoK(OAc)2, operate by different mechanisms for PO/PA and PO/CO2 ROCOP. The new wide separation catalyst, LwideCoK(OAc)2, shows some of the best performances yet reported for PO/PA ROCOP, and suggests other catalysts featuring larger intermetallic separations should be targeted for epoxide/anhydride copolymerizations.

Synthesis of Amphiphilic Amino Poly-Amido-Saccharide and Poly(lactic) Acid Block Copolymers and Fabrication of Paclitaxel-Loaded Mucoadhesive Nanoparticles.

Drug delivery to the esophagus through systemic administration remains challenging, as minimal drug reaches the desired target. Local delivery offers the potential for improved efficacy while minimizing off-target toxicities but necessitates bioadhesive properties for mucosal delivery. Herein, we describe the synthesis of two new mucoadhesive amphiphilic copolymers prepared by sequential ring-opening copolymerization or postpolymerization click conjugation. Both strategies yield block copolymers containing a hydrophilic amine-functionalized poly-amido-saccharide and either a hydrophobic alkyl derivatized poly-amido-saccharide or poly(lactic acid), respectively. The latter resulting copolymers readily self-assemble into spherical, ≈200 nm diameter, positively charged mucoadhesive nanoparticles. The NPs entrap ultrahigh levels of paclitaxel via encapsulation of free paclitaxel and paclitaxel conjugated to a biodegradable, biocompatible poly(1,2-glycerol carbonate). Paclitaxel-loaded NPs rapidly enter cells, release paclitaxel, are cytotoxic to esophageal OE33 and OE19 tumor cells in vitro, and, importantly, demonstrate improved mucoadhesion compared to conventional poly(ethylene glycol)-poly(lactic acid) nanoparticles to ex vivo esophageal tissue.

Photochemical [2 + 2] Cycloaddition Enables the Synthesis of Highly Thermally Stable and Acid/Base-Resistant Polyesters from a Nonpolymerizable α,β-Conjugated Valerolactone.

We report a simple strategy to transform a nonpolymerizable six-membered α,β-conjugated lactone, 5,6-dihydro-2H-pyran-2-one (DPO), into polymerizable bicyclic lactones via photochemical [2 + 2] cycloaddition. Two bicyclic lactones, M1 and M2, were obtained by the photochemical [2 + 2] cycloaddition of tetramethylethylene and DPO. Ring-opening polymerization (ROP) of M1 and M2 catalyzed by diphenyl phosphate (DPP), La[N(SiMe3)2]3, and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris (dimethylamino) phosphoranylide-namino]-2λ5, 4λ5-catenadi(phosphazene) (tBu-P4) were conducted. M1 is highly polymerizable, either DPP or La[N(SiMe3)2]3 could catalyze its living ROP under mild conditions, affording the well-defined PM1 with a predictable molar mass and low dispersity. M2 could only be polymerized with tBu-P4 as the catalyst, also generating the same polymer PM1. PM1 has high thermal stability, with a Td,5% being up to 376 °C. Ring-opening copolymerization (ROcP) of M1 and δ-valerolactone (δ-VL) catalyzed by La[N(SiMe3)2]3 afforded a series of random copolymers with enhanced thermal stabilities. Both PM1 and the copolymer containing 10 mol % M1 exhibited excellent resistance to acidic and basic hydrolysis. Our results demonstrate that direct photochemical [2 + 2] cycloaddition of α,β-conjugated valerolactone is not only a strategy to tune its polymerizability, but also allows for the synthesis of highly thermally stable aliphatic polyesters, inaccessible by other methods.

Thioester-rich degradable copolymers from a thionolactone and S-vinyl and P-vinyl monomers

The recent advent of the radical thiocarbonyl addition–ring-opening (TARO) copolymerization of thionolactones with vinyl monomers enables the production of degradable thioester backbone-functional vinyl copolymers promising for recycling and biomedical applications. To better understand the copolymerization behaviour of the prototypical thionolactone, dibenzo [c,e]oxepin-5(7H)-thione (DOT), copolymers with three S- and P-vinyl comonomers, phenyl vinyl sulfide (PVS), phenyl vinyl sulfone (PVSO), and diethyl vinylphosphonate (DEVP) were prepared through free and RAFT radical polymerizations. In all cases, DOT was incorporated faster than the vinyl comonomers which led to copolymers with up to 89 mol-% DOT content—surprising in light of past reports of significant retardation for high DOT feeds. All copolymers proved readily degradable. A postpolymerization oxidation enabled the conversion of a DOT–PVS copolymer into a corresponding DOT–PVSO species that remained degradable and offered a synthetic strategy to prepare copolymers with compositions not accessible through a direct copolymerization.

Zinc ferro- and ferri-cyanides catalyst structures from point of colloid chemistry view

The aim of this research was to comprehensively analyze zinc ferro- and ferri-cyanides for rationally choose or modify hexacyanoferrates in a range of application focused on catalysing the ring-opening copolymerization of epoxides and CO2 to reduce the environmental toll. Scripts of the synthesis of 14 samples with variable morphology are given. Thermogravimetry, FT-IR, and XRD indicates the formation of two predominant types of bridging cyanide groups with different coordination environment, which accounts for a lack crystallinity aggregate with an amorphous part. Involving dynamic light scattering and laser Doppler electrophoresis as distinguishing features the formation of colloidal fractions is demonstrated and characterized. The switch from a negative surface rich in Lewis basic sites (Me–CN–) to a surface rich in open-metal sites is either jump and stepwise successfully completed. The proposed structures of micelles of the catalysts allow great attention to be paid to every small detail of their catalytic activity.

The use of carbodicarbene for bio-based polyester synthesis via ring-opening copolymerization of cyclic anhydrides and epoxides

Alternating ring-opening copolymerization (ROCOP) of epoxides and cyclic anhydrides was investigated using carbodicarbene (CDC) as a single-component organic initiator. CDC produced various polyesters with different combinations of monomers, including bio-based monomers. The synthesized polyesters exhibited narrow dispersity and a wide range of glass transition temperatures. Moreover, a diblock copolyester was synthesized using self-switchable polymerization (ROCOP of the cyclic anhydride/epoxide, and ring-opening polymerization of lactone) in a one-pot synthesis. The formation of a terpolymer product was confirmed by diffusion-ordered spectroscopy and thermal gravimetric analysis.

Synthesis of poly(thiourethane-alt-thioester) by alternating ring-opening copolymerization of N-thiocarboxyanhydrides and episulfides

Synthesis of poly(thiourethane-alt-thioester) by alternating ring-opening copolymerization of N-thiocarboxyanhydrides and episulfides

Closed-Loop Recycling of Mixed Plastics of Polyester and CO2-Based Polycarbonate to a Single Monomer.

Physical blending is an effective strategy for tailoring polymeric materials to specific application requirements. However, physically blended mixed plastics waste adds additional barriers in mechanical or chemical recycling. This difficulty arises from the intricate requirement for meticulous sorting and separation of the various polymers in the inherent incompatibility of mixed polymers during recycling. To overcome this impediment, this work furthers the emerging single-monomer - multiple-materials approach through the design of a bifunctional monomer that can not only orthogonally polymerize into two different types of polymers - specifically lactone-based polyester and CO2-based polycarbonate - but the resultant polymers and their mixture can also be depolymerized back to the single, original monomer when facilitated by catalysis. Specifically, the lactone/epoxide hybrid bifunctional monomer (BiLO) undergoes ring-opening polymerization through the lactone manifold to produce polyester, PE(BiLO), and is also applied to ring-opening copolymerization with CO2, via the epoxide manifold, to yield polycarbonate, PC(BiLO). Remarkably, a one-pot recycling process of a BiLO-derived PE/PC blend back to the constituent monomer BiLO in >99 % selectivity was achieved with a superbase catalyst at 150 °C, thereby effectively obviating the requirement for sorting and separation typically required for recycling of mixed polymers.

Preparation of an Antibacterial Branched Polyamide 6 via Hydrolytic Ring-Opening Co-Polymerization of ε-Caprolactam and Lysine Derivative.

In this study, we successfully realized the hydrolytic ring-opening co-polymerization of ε-caprolactam (CPL) and lysine derivative. A novel antibacterial modified polyamide 6 with a branched structure was obtained after the quaternization of the co-polymers. The co-polymers exhibited a significant increase in zero shear viscosity, melt index and storage modulus at the low frequency region. The quaternized co-polymers displayed thermal properties different from pure PA6 and good mechanical (tensile) properties. The antibacterial activity of the quaternized co-polymers depends on the quaternary ammonium groups' incorporated content. At 6.2 mol% incorporation of quaternary ammonium groups, the strong antibacterial activity has been introduced to the co-polymers. As the quaternary ammonium groups approached 10.1 mol%, the antibacterial polymers demonstrated nearly complete killing of Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative). The above research results provided a new approach for the study of high-performance nylon.

Highly active organocatalyst from a trivalent phosphazenium salt for ring-opening copolymerization of epoxides and cyclic anhydrides enhanced by hydrogen bonding interactions

Highly active organocatalyst from a trivalent phosphazenium salt for ring-opening copolymerization of epoxides and cyclic anhydrides enhanced by hydrogen bonding interactions