Sulfur-containing Polymers Research Articles

Sulfur-containing cellulose esters for selectively anchoring gold for water catalytic decontamination

The facile preparation of sustainable sulfur-containing polymer functional materials has been obtained great attention due to their chemical reactivity and metal complexing ability. In this study, taking the solution properties advantages of the newly developed cellulose solvent system of DBU/DMSO/CO2, thiol and disulfide bond functionalized cellulose ester (TDSCE) was facilely prepared via in-situ tandem transesterification and oxidation reaction by using methyl 3-mercaptopropionate, without adding any external catalyst. The synthetic protocol was featured by that the DBU not only acted as reagent for the dissolution of cellulose, but also catalysts for the transesterification of cellulose with methyl 3-mercaptopropionate to yield cellulose 3-mercaptopropionate (Cell-MP) with maximum degrees of substitution (DS) of 0.77, and an oxidant for the partial oxidation of Cell-MP to produce a cellulose methyl 3,3′-disulfanediyldipropionate (Cell-MDSP) with maximum DS of 0.36 mixed ester, respectively. With successful introduction of thiol and disulfide bond into the cellulose backbone, the TDSCEs indicated desirable selective absorption of Au3+ from mimic heavy mental ions waste water due to the sulfur-Au chemistry with maximal adsorption capacity for Au3+ of 415.2 mg/g. The subsequent reduction of Au3+ into gold nanoparticles (Au NPs) fabricated a robust TDSCE-2@Au NPs composite catalyst with high catalytic activity for the hydrogenation treatment of water pollutes, such as 4-nitrophenol (4-NP)and azo dyes.

NaOH-Assisted Multicomponent Reaction and Polymerizations of Elemental Sulfur, Diisocyanides, and Diols to Access Functional Poly(O-thiocarbamate)s.

Sulfur-containing polymers with unique structures and fascinating properties have attracted much attention recently, the efficient and economic synthetic approaches for various sulfur-containing polymers have rapidly developed. Herein, the multicomponent reaction of elemental sulfur, isocyanide, and alcohol was designed at mild condition with the assistance of NaOH, and the corresponding NaOH-assisted multicomponent polymerization of elemental sulfur, diisocyanides, and diols were developed at room temperature or 40 oC in air, to produce poly(O-thiocarbamate)s with well-defined structures, high molecular weights (Mws up to 32 500 g/mol) and high yields (up to 99%). The facilely available monomers, mild condition, and high efficiency of this MCP enabled scale-up synthesis of poly(O-thiocarbamate)s, and 7.34 g polymer was obtained in 98% yield. These functional poly(O-thiocarbamate)s could enrich Au3+ from aqueous solution with high enrichment capacity (983 mg·Au3+/g) and high efficiency (>99.99%) in 1 min, demonstrating superior gold enrichment performance and their potential industrial and economic values.

Sulfur-containing polymers for enhancing rate and cycle performance of lithium-sulfur batteries

Sulfur-containing polymer with covalent C-S bonds has become an ideal alternative cathode of element sulfur for lithium-sulfur battery. However, the rational design of polymer structure with high sulfur content and enhanced electrochemical performance of Li-S battery is still a great challenge. In this study, a facial synthesis of sulfur-containing polymer by using 1,2,3-trichloropropane and sulfur as starting materials at a mild condition was reported, and the covalent anchoring of the C-S bonds within the polymer effectively inhibited the shuttle effect of polysulfides, providing a splendid internal environment for the diffusion of lithium ions. As a result, the rich sulfur content (higher than 80 %) and its homogeneous distribution in the polymer backbone determined the excellent rate performance of obtained sulfur-containing polymers. In terms of cycling performance, the reversible specific capacity of the battery is 396 mAh/g after 500 cycles at a current density of 0.5 A/g and 350 mAh/g after 800 cycles at 1 A/g, with a capacity decay of only 0.06 % per cycle.

Unleashing the potential of sulfur-incorporated polymer framework composite for enhanced performance and stability of lithium-organosulfur batteries

Sulfur-containing polymer have emerged as a promising cathode material due to their high theoretical capacity, energy density and low cost. However, their commercial development is hindered by the shuttle effect and slow lithium-ion transport efficiency. Here, a novel sulfur-containing polymer framework material (1,4-NDC@S@PAA) was synthesized by using a solid-phase reaction method. The carbon skeleton of polyacrylic acid (PAA) is functionalized with both 1,4-naphthalenedicarboxylic acid (1,4-NDC) and sulfur molecular clusters. By incorporating small molecules into the carbon skeleton, the lithium-ion transport channels within the electrode material are increased, resulting in improved performance. Compared to traditional vulcanized sulfur chain-type polymers, employing PAA as the main chain enhances stability during charge/discharge process. After 500 cycles at 1.0 C, the material demonstrates a modest average decay rate of 0.091% per cycle. Additionally, the introduction of 1,4-NDC constructs a molecular framework that facilitates rapid Li+ ions diffusion, leading to a two-order of magnitude increase of Li+ ions diffusion coefficient as high as 3.58×10−8 cm2 s−1 and excellent rate performance with a 721 mAh g−1 specific capacity at 5.0 C. This high-performance sulfur-containing polymer framework material holds great promise for advancing lithium-sulfur battery technology and addressing the limitations faced by traditional lithium-ion batteries.

O/S Exchange Reaction in Synthesizing Sulfur-Containing Polymers.

Using carbon disulfide (CS2) and carbonyl sulfide (COS) as sulfur-containing and one-carbon feedstocks to make value-added products is paramount for both pure and applied chemistry and environmental science. One of the practical strategies is to copolymerize these bulk chemicals with epoxides to produce sulfur-containing polymers. This approach contributes to improving the sustainability of polymer manufacturing, provides highly desired functional polymer materials, and has attracted much attention. However, these copolymerizations invariably exhibit the intensely complicated chemistry of O/S exchange reaction, leading to sulfur-containing polymers with diverse architectures. As the understanding of O/S exchange continues to deepen, recent efforts have guided significant advances in the synthesis of CS2- and COS-based polymers. This review examines the O/S exchange chemistry and summarizes the recent progress in this field to promote the further advance of synthesizing sulfur-containing polymers from CS2 and COS.

Green conversion of carbon disulfide to degradable polydithiourethanes through catalyst-free multicomponent polymerizations of diamines, carbon disulfide and diacrylates

In the pursuit of advanced functional polymer materials, sulfur-containing polymers have received tremendous attention owing to their superior chemical stability, high refractive indices, various supramolecular interactions, and robust dynamic covalent chemistry. However, their synthesis usually involves either expensive monomers or toxic byproducts and requires catalysts, thus hindering their widespread application. In this work, we present a catalyst-free multicomponent polymerization in organic solvents for the synthesis of various polydithiourethanes with excellent yields (up to 98 %) and high molecular weights (up to 112 kg/mol). This reaction involves the direct polymerization of carbon disulfide, an abundant one-carbon feedstock, with commercially available diamines and diacrylates. This polyaddition process demonstrates high atom economy and no byproduct, occurring at room temperature without the need for a catalyst, thus exhibiting excellent green chemistry metrics. By utilizing the dynamic covalent chemistry of dithiourethane groups, these polymers can be efficiently degraded via aminolysis and used to fabricate reprocessable vitrimers. This multicomponent polymerization opens up a new avenue for the efficient utilization of carbon disulfide resources and accelerates the exploration of diversified sulfur-containing functional polymer materials.

Oxygen-initiated radical ring-opening polymerization of macrocyclic allylic sulfides under ambient conditions

Although radical ring-opening polymerization (ROP) is a powerful approach for synthesizing polymers with diverse backbone structures, the intrinsic oxygen sensitivity of radicals challenges the ability to perform these polymerizations under air conditions. Here, we reported a novel oxygen-initiated radical ROP of macrocyclic allylic sulfides that can efficiently proceed under an air atmosphere, enabling the construction of sulfur-containing polymers with moderate to high molecular weights. The versatility of this approach was further demonstrated by copolymerizing macrocyclic allylic sulfides with vinyl monomers to create degradable vinyl polymers under ambient conditions. Density functional theory calculations revealed that the quenching of radicals by oxygen in the chain-growth process was kinetically disfavored, thereby allowing the polymerization to be compatible with oxygen. This work will further advance applications of radical ROP in diverse fields by enhancing its tolerance towards oxygen.

Preparation of imidazole-based polymeric ionic liquid catalysts and their catalysis in the copolymerization with sulfur dioxide

Sulfur dioxide (SO2) is one of the primary air pollutants, and its reaction with epoxides to produce sulfur-containing polymers is an efficient means of resource utilization for SO2, however, catalysts play a crucial role in this reaction. Polymeric ionic liquids (PILs) have become a hot topic in catalysis research due to their dual characteristics of ionic liquids and polymers. Therefore, a series of heterogeneous PILs were prepared, characterized, and employed for the copolymerization of SO2 with epoxides in this study. The impact of different halide anions and hydrogen bond donors on catalytic performance was investigated. Optimal reaction conditions for copolymerization were determined by examining reaction temperature, reaction time, molar ratio of catalyst to epoxide, and other factors. Furthermore, PILs demonstrated recyclability for more than 6 cycles without a significant decrease in catalytic activity, and PILs exhibited broad applicability to various epoxides. Finally, density functional theory (DFT) calculations were employed to further elucidate the activation effect of halide anions and hydrogen bond donors on epoxides to propose a potential mechanism for the copolymerization of SO2 with epoxides catalyzed by PILs.

Engineering of uniform spherical sulfur-containing polymer with short sulfur chain as cathode material for highly durable lithium storage

Lithium-sulfur battery has ultra-higher theoretical specific capacity (1675 mA h g−1) and theoretical energy density (2600 W h kg−1) compared with other commercially applied rechargeable battery system. However, some drawbacks, such as shuttle effect, poor conductivity and so on, disrupt the process of its industrialization and commercializes. In this study, spherical sulfur-containing polymer with short sulfur chain (sulfur chain length controlled at -S2-) was synthesized as cathode material for lithium storage. Two sulfur-containing polymer samples with particle size of 300 nm and 1000 nm were designed and synthesized to investigate the electrochemical properties of lithium storage. The obtained two sulfur-containing polymer cathode materials both exhibit higher lithium electroactivity with only one single discharge plateau at 2.1 V. Moreover, the cathode material with larger particle size displays faster reaction kinetics, showing stable long cyclic performance, i.e. and high specific capacity of 618 mA h g−1 after 150 cycles at a current density of 100 mA g−1.

Polymer Complexes of Amikacin with Sulfur-Containing Polymers

Polymer Complexes of Amikacin with Sulfur-Containing Polymers

Tailoring Interfacial Electric Field by Gold Nanoparticles Enable Electrocatalytic Lithium Polysulfides Conversion for Lithium-Sulfur Batteries.

Although lithium-sulfur batteries (LSBs) are considered as the promising next rechargeable storage system ascribing to their decent specific capacity of inorganic sulfur, the development is partially impeded by inferior electronic conductivity, severe shuttle effect, and large volume variation. To tackle the issues above, a great deal of effort is made on sulfur-containing polymer (SCP) that shows better electrochemical performance. Nevertheless, sluggish conversion of lithium polysulfides (LiPSs) obstructs battery performance yet. Herein, electrocatalytic LiPSs with full conversion by tailoring the interfacial electric field are discovered based on gold nanoparticles (AuNPs) anchored on sulfurized polyaniline (SPANI). A downhill path of Gibbs free energy from organosulfur polymer to intermediate product means more spontaneously and favorable for full conversion, as the significant enhancement of electron density of state in the vicinity of the HOMO level for the AuNPs increase the electron transition probability rate. This composite delivers satisfactory electrochemical performance, especially increased rate capacity of >300 mAh g-1. Furthermore, catalyst mechanism on molecule level is proposed that AuNPsdominate chemical enhancement and higher electron delocalizablility betweenAuNPs and LiPSs molecules. These results can erect a promising strategy for enhancing lithium polysulfides full conversion.

Room temperature synthesis, characterization and enhanced gas transport properties of novel poly(oxindolylidene arylene)s with dibenzothiophene, dibenzothiophene-S-oxide and dibenzothiophene-S,S-dioxide fragments in the main chain

Aromatic sulfur-containing polymers poly(arylene ether sulfone)s and poly(arylene sulfide sulfone)s are widely used in membrane-based gas- and liquid separations and purification technologies. In this work, we report a facile, robust, room temperature synthesis of a series of novel, solution processable aromatic polymers containing dibenzothiophene, dibenzothiophene-S-oxide, and dibenzothiophene-S,S-dioxide fragments in the main chain, alternating with bulky, torsion resistant oxindolylidene groups. The NMR studies of the polymers obtained revealed ladderized, rigid kink-structured backbones. This combination provides membranes with higher permeability and selectivity with gas pairs CO2/CH4, H2/CH4 and H2/N2, close to or even surpassing the 2008 Robeson’s trade-off line, that compare favorably with polysulfones and poly(ether sulfone)s reported in the literature that lie below the 1991 upper bond. Polymer P2-SO2 containing dibenzothiophene-S,S-dioxide fragments showed impressive CO2 and H2 permeabilities (243. 3 and 315.1 Barrer, respectively); on the other hand, P1-SO containing dibenzothiophene-S-oxide exhibited remarkable H2/CH4 and H2/N2 selectivity (127.26 and 99.34, respectively). This work offers a novel and facile route to fabricate various polysulfones and polysulfoxides with reversible-tunable gas separation properties inspired by the concept of rigid kink-structured backbones that shift their gas transport properties towards higher permeability and higher selectivity.

Recent Progress in Sulfur-Containing High Refractive Index Polymers for Optical Applications.

The development in the field of high refractive index materials is a crucial factor for the advancement of optical devices with advanced features such as image sensors, optical data storage, antireflective coatings, light-emitting diodes, and nanoimprinting. Sulfur plays an important role in high refractive index applications owing to its high molar refraction compared to carbon. Sulfur exists in multiple oxidation states and can exhibit various stable functional groups. Over the last few decades, sulfur-containing polymers have attracted much attention owing to their wide array of applications governed by the functional group of sulfur present in the polymer repeat unit. The interplay of refractive index and various other polymer properties contributes to successfully implementing a specific polymer material in optical applications. The focus on developing optoelectronic devices induced an ever-increasing need to integrate different functional materials to achieve the devices' full potential. Several devices that see the potential use of sulfur in high refractive index materials are reviewed in the study. Like sulfur, selenium also exhibits high molar refraction and unique chemical properties, making it an essential field of study. This review covers the research and development in the field of sulfur and selenium in different forms of functionality, focusing on the chemistry of bonding and the optical properties of the polymers containing the heteroatoms mentioned above. The strategy and rationale behind incorporating heteroatoms in a polymer matrix to produce high-refractive-index materials are also described in the present review.

Step-growth Polymerization of Aziridines with Elemental Sulfur: Easy Access to Linear Polysulfides and Their Use as Recyclable Adhesives.

The bulk radical polymerization of bis(aziridine) with molten elemental sulfur resulted in brittle, cross-linked polymers. However, when the bis(aziridine) was treated with elemental sulfur in the presence of an organobase, the ring-opening reaction of aziridine with oligosulfide anions occurred, leading to the formation of linear polymers by step-growth polymerization. These newly synthesized polymers possess repeating units containing a sulfonamide or amide functional moiety and oligosulfide bonds with an average sulfur segment of about two. A small molecular model reaction confirmed the nucleophilic addition reaction of elemental sulfur to aziridine. It was verified that S-S dynamic bond exchange takes place in the presence of an organic base within the linear chains. The mixture of the synthesized polysulfides with pyridine exhibits exceptional adhesive properties when applied to steel, and aluminum substrates. Notably, these prepared adhesives displayed good reusability due to the dynamic S-S exchange and complete recyclability due to their solution processability. This elemental sulfur-involved polymerization approach represents an innovative method for the synthesis of advanced sulfur-containing polymers, demonstrating the potential for various applications in adhesives and beyond.

Green synthesis of sulfur-containing polymers by carbon disulfide-based spontaneous multicomponent polymerization

A spontaneous multi-component polymerization of activated internal alkynes, amines, and CS2 was established. Similar to the ancient “tenon and mortise” structure, CS2 acts as a “wedge” to link the other two monomers to form sulfur-containing polymers.

Monomer centred selectivity guidelines for sulfurated ring-opening copolymerisations.

Sulfur-containing polymers, such as thioesters and thiocarbonates, offer sustainability advantages, including enhanced degradability and chemical recyclability. However, their synthesis remains underdeveloped compared to that of their oxygen-containing counterparts. Although catalytic ring-opening copolymerization (ROCOP) can provide access to sulfur-containing polymers, these materials often exhibit uncontrolled microstructures and unpredictable properties. A comprehensive model that elucidates the factors determining selectivity in these catalytic reactions is still lacking, despite its central importance for advancing these polymerizations into widely applicable methodologies. In this study, we investigate the factors that lead to selectivity in sulfurated ROCOP across various monomer combinations, including thioanhydrides or carbon disulfide with epoxides, thiiranes, and oxetanes. We find that unwanted by-products primarily arise from backbiting reactions of catalyst-bound alkoxide chain ends, which can be mitigated by (i) selecting monomers that form primary alkoxide of thiolate chain ends, (ii) maximizing ring strain in the backbiting step, and (iii) timely termination of the polymerization. By applying these strategies, the selectivity of the catalytic ROCOP can be controlled and we successfully synthesized perfectly alternating poly(esters-alt-thioesters) from various oxetanes and the highly industrially relevant ethylene oxide. Our study thereby shifts the focus for achieving selectivity from catalyst to monomer choice providing valuable mechanistic insights for the development of future selective polymerizations, paving the way for sulfurated polymers as potential alternatives to current commodity materials.

Unsaturated sulfur-containing polymers from modular alcohol click chemistry

A modular and efficient click reaction for connecting primary and secondary alcohols with activated alkynes via carbonyl sulfide (COS) was developed. Polythiocarbonates were synthesized by the step-wise polyaddition of diols, dipropiolates, and COS.

Doped activated carbons obtained from nitrogen and sulfur-containing polymers as metal-free catalysts for application in nitroarenes hydrogenation

Activated carbons doped with nitrogen and/or sulfur have been obtained by pyrolysis followed of steam activation of a sulfur containing polymer (polythiophene) and two nitrogen-containing polymers (polyaniline and polypyrrole). These polymers were synthesized by oxidative chemical polymerization in aqueous media of their corresponding monomers.The influence of the steam activation on the textural properties and surface chemistry of the carbons has been evaluated and their catalytic activity has been determined in the hydrogenation reaction of 1-chloro-4-nitrobenzene. The degree of conversion in the reaction depends on the development of adequate porosity in the activated carbon (which is determined by the activation conditions) together with the presence of heteroatoms that act as active catalytic sites, with S showing considerably greater effectiveness than N. A compromise between an acceptable level of doping with sulfur and an adequate porosity is necessary, which has been achieved in a carbon obtained from polythiophene pyrolyzed at 900 °C and steam activated at 800 °C for 4 h, with a specific surface area of 742 m2/g and S content of 1.71 at%.

Controlled and Regioselective Ring-Opening Polymerization for Poly(disulfide)s by Anion-Binding Catalysis.

Poly(disulfide)s are an emerging class of sulfur-containing polymers with applications in medicine, energy, and functional materials. However, the constituent dynamic covalent S-S bond is highly reactive in the presence of the sulfide (RS-) anion, imposing a persistent challenge to control the polymerization. Here, we report an anion-binding approach to arrest the high reactivity of the RS- chain end to control the synthesis of linear poly(disulfide)s, realizing a rapid, living ring-opening polymerization of 1,2-dithiolanes with narrow dispersity and high regioselectivity (Mw/Mn ∼ 1.1, Ps ∼ 0.85). Mechanistic studies support the formation of a thiourea-base-sulfide ternary complex as the catalytically active species during the chain propagation. Theoretical analyses reveal a synergistic catalytic model where the catalyst preorganizes the protonated base and anionic chain end to establish spatial confinement over the bound monomer, effecting the observed regioselectivity. The catalytic system is amenable to monomers with various functional groups, and semicrystalline polymers are also obtained from lipoic acid derivatives by enhancing the regioselectivity.

Triazine-based sulphur-containing polymers for Hg2+ adsorption: Efficiency and mechanism

Recently the research on the materials for removal of heave metals is surging rapidly. Here we have studied four triazine-based sulfur-containing polymers with different linkers, namely PDT1, PDT2, EDT1, and EDT2. They have been successfully synthesized by the nucleophilic substitution reaction of cyanuric chloride with propane-1,3-dithiol (PDT1 and PDT2) and ethane-1,2-dithiol (EDT1 and EDT2) in different ratios. The physical and chemical properties of these polymers were characterized by scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, porous structure analysis and X-ray photoelectron spectroscopy. The optimized adsorption condition was established by examining dosing, co-existing substances, contact time, concentration, temperature and pH values. The adsorbing properties, which was mainly described by the pseudo-second-order kinetic and Langmuir isothermal model, indicated that the sorption of Hg2+ was the chemical adsorption. The maximum Hg2+ sorption capacities of PDT1, PDT2, EDT1 and EDT2 were 1440.97 mg g−1, 715.99 mg g−1, 237.87 mg g−1 and 181.48 mg g−1, respectively. Thermodynamically, the adsorption of Hg2+ by the adsorbent is a spontaneous process. Cyclic experiments demonstrated that all the adsorbents could be reused in five successive adsorption cycles without significant losses in performance. Our density functional theory calculations in combination with relevant experimental results revealed the coordination geometry of Hg and hence mercury-adsorbent chelation mechanism. These results suggested that triazine-based sulfur-containing polymers could be utilized as effective adsorbents for the removal of Hg2+ from polluted water.