Bulk Monomer Research Articles

High-performance polyurea nanofiltration membrane for waste lithium-ion batteries recycling: Leveraging synergistic control of bulk and interfacial monomer diffusion

The development of high-performance nanofiltration (NF) membranes with extreme chemical stability is urgently needed for the recovery of spent lithium. In this study, a series of polyurea membranes with high lithium recovery efficiency and pH stability were fabricated by zone-regulated interfacial polymerization (IP). The reaction inhibitor Cu2+ in the bulk aqueous phase reduces IP intensity by reversibly binding to the amino groups of polyethyleneimine monomers through chelate bonds. Meanwhile, surfactant promote the uniform diffusion of macromolecular aqueous monomers at the phase interface. The milder polymerization reaction and the more stable phase interface endow the polyurea membrane (NF10k PEI-SDS-Cu2+) with higher water permeance (2.1 L m-2 h-1 bar-1), desirable MgCl2 rejection (94.7%), and excellent fabrication repeatability. Moreover, the membrane demonstrates stable separation selectivity for Co2+/Li+ and SO42-/Li+ under conditions of 0.05 mol L-1 H2SO4 and 2 mol L-1 LiOH, respectively. Our study provides a facile method for constructing NF membranes with extreme pH stability and confirms the feasibility of membrane-based lithium recovery.

Anionic Conjugate Addition Oligomerization of Carbon Dioxide/Butadiene Derived Lactones.

Nucleophilic and non-nucleophilic bases have been employed in anionic oligomerization of unsaturated δ-valerolactone (3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one) (1). Compared to the seminal findings with 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), the unsaturated lactone reacts with guanidines, disilazanes, and phosphazenes both in bulk and in solution with higher productivities and activities, reaching full conversion with turnover frequencies up to 382 h-1. Additionally, reactions using phosphazenes and NaHMDS were active at 1 mol % catalyst loadings both in solvent and in bulk monomer at room temperature. Characterization of the reaction products by 1H, 13C, FTIR, MALDI-MS, tandem mass spectrometry (MS/MS), and ion mobility mass spectrometry (IM-MS) revealed microstructural differences dependent on the nucleophilicity of the organocatalytic base and reaction conditions. The products from phosphazene-catalyzed reactions are consistent with selective vinylogous 1,4-conjugate addition, whereas both conjugate addition and ring-opening mechanisms are observed in TBD. DSC reveals that these microstructures can be tuned to have a Tg range between -18 and 80 °C, while SEC and MALDI-MS reveal that only low molar mass oligomers are formed (748-5949 g/mol). From these results, an approach for selectively favoring the vinylogous 1,4-conjugate addition pathway is obtained over ring-opening reactivity.

Advancing the material performance of chemically recyclable polythioesters via copolymerization

Developing new chemically recyclable polymers provides an opportunity for establishing a circular plastic economy. However, it is still challenging to reconcile both polymer recyclability and material properties. Herein, we aimed to exploit copolymerization of 3-methyl-dithian-2-one (Me-DTO) and thiovalerolactone (TVL) to access chemically recyclable polythioesters with high-performance material properties. Adjusting the copolymer compositions allowed to modulate the thermal and mechanical properties of the resulting copolymers extensively. Ultimately, polyolefin-like mechanical properties was achieved for P[(Me-DTO)100-co-(TVL)900] (σB = 33.87 ± 4.79MPa and εB = 638 % ± 112 %). These copolymers were capable of depolymerizing into their monomers in solution or bulk efficiently with high yields of >95 %, thus establishing their circular life cycle.

Group transfer polymerization in bulk methacrylates

AbstractGroup transfer polymerization (GTP) is a polymerization method developed to obtain targeted (meth)acrylic polymers in solution at ambient temperatures. In this work, it is employed with methacrylic monomers to obtain low Ð polymers in bulk. In this regard, different initiator systems that exhibit different mechanisms are compared concerning the molecular weight, the polydispersity and double bond conversion of the resulting bulk polymers. The respective systems were chosen carefully to give a broad overview of earlier developed initiator‐catalyst combinations 1‐methoxy‐1‐(trimethylsiloxy)‐2‐methylprop‐1‐ene (MTS) & tetrabutylammonium cyanide (TBACN) and more recently investigated initiating systems MTS & trityl tetrakis(pentafluorophenyl)borate (TTPB) or dimethyl phenyl silane (DMPS) & tris(pentafluorophenyl)borate (BCF). The described initiating systems are applied as a two‐component (2K) system to ensure a homogeneous distribution of the respective initiator and catalyst in the bulk monomer. In addition to the 2K experiments, photochemical initiation is also applied to bulk formulations. Therefore, a photoacid generator (PAG) and MTS is used to trigger the polymerization reaction by irradiation with UV light. A highly controlled photopolymerization method in bulk was developed that way achieving a low polydispersity polymer with high double bond conversion.

Analyzing the binding affinity of potential homodimers produced by the C55 portion of the amyloid precursor protein, a molecular dynamics study.

Alzheimer's disease is a neurodegenerative disease that affects millions of people in the United States alone. Agglomeration of amyloid beta (Aβ) peptides is a potential cause of the disease and the loss of mental acuity it induces. Aβ is created via the cleavage of the amyloid precursor protein (APP). When APP is cleaved, part of it—approximately the C99 fragment—remains in the lipid membrane, with its N-terminus being the Aβ peptide. The dimerization of C99 is theorized to limit its further cleavage and thereby limit the production of Aβ. However, this has yet to be proven experimentally. The first 55 residues of the C99 fragment (called C55) contains both the transmembrane domain and Aβ. In this work, we explored multiple potential conformations of C55 dimers (starting from the PDB ID 2LP1) and calculated their binding affinity to better understand the viability of homodimerization. The homodimer conformations were explored using both implicit and explicit water Molecular Dynamics simulations. We used an Extended Adaptive Biasing Force method to calculate the binding affinity of these dimers in a POPC lipid membrane. This methodology is characterized by the use of a continuously updated biasing force that cancels all force along a specified reaction coordinate and, in this way, enables uniform sampling on a flat free-energy surface. Applying this methodology using collective variables for root-mean-square deviation, spin, tilt, and Euclidean distance for both the bulk (monomer) and bound (dimer) states, we compute a binding affinity of roughly −4 kcal/mol for one of our dimer conformations. This lends in silica credence to the hypothesis that the dimerization of C55 limits the formation of Aβ, as the dimer appears energetically viable.

Production of citramalate in Escherichia coli by mediating colonic acid metabolism and fermentation optimization

Citramalic acid (citramalate) is important for the chemical synthesis of methylmethacrylate, a bulk monomer used for manufacturing biodegradable polymers. Escherichia coli strains have been engineered for the biological production of citramalate since a rare mutant of citramalate synthase was invented as a mesophilic catalyzer to form the chemical. However, acidic byproducts are routinely excreted by E. coli host cells during fermentation, which could significantly reduce the carbon conversion efficiency of biosynthetic chemicals, including citramalate. Herein, an unusual mutant called S17–3 was reported, and this mutant demonstrated superb recovery efficacy from glucose to citramalate and secreted a very low level of fermentation byproducts during the fermentative production of citramalate. However, S17–3 tends to produce a large amount of colonic acid (CA). Genetically manipulating the regulators involved in CA synthesis revealed that the deletion of rcsD could significantly improve the citramalate titer. Fed-batch fermentation under optimized conditions led to a maximum titer of 46.2 g/L citramalate accumulated in the broth, with a conversion efficiency of 0.80 g citramalate per gram glucose and a close-to-the-theoretical mole transversion efficiency (mol/mol) of 0.97. This study facilitates the development of a practical bioproduction of citramalate using E. coli strains.

Biobased High-Performance Aromatic-Aliphatic Polyesters with Complete Recyclability.

The development of high-performance recyclable polymers represents a circular plastics economy to address the urgent issues of plastic sustainability. Herein, we design a series of biobased seven-membered-ring esters containing aromatic and aliphatic moieties. Ring-opening polymerization studies showed that they readily polymerize with excellent activity (TOF up to 2.1 × 105 h-1) at room temperature and produce polymers with high molecular weight (Mn up to 438 kg/mol). The variety of functionalities allows us to investigate the substitution effect on polymerizability/recyclability of monomers and properties of polymers (such as Tgs from -1 to 79 °C). Remarkably, a stereocomplexed P(M2) exhibited significantly increased Tm and crystallization rate. More importantly, product P(M)s were capable of depolymerizing into their monomers in solution or bulk with high efficiency, thus establishing their circular life cycle.

The effect of hydrogen bonding on the copolymerization kinetics of 2‐methoxyethyl acrylate with 2‐hydroxyethyl methacrylate in alcohol and aqueous solutions

AbstractThe influence of alcohol and alcohol/water solutions on the radical copolymerization kinetics of 2‐hydroxyethyl methacrylate (HEMA) with 2‐methoxyethyl acrylate (MEA) is studied using pulsed‐laser‐polymerization coupled with size exclusion chromatography. It is found that MEA incorporation into the copolymer is increased in butanol, methanol (MeOH), and MeOH/H2O solutions relative to the bulk system. Copolymer composition can be represented for solvent levels ≥50 vol.% by a single pair of reactivity ratios ( = 2.39 ± 0.16, = 0.28 ± 0.02) that differ from those in bulk ( = 3.14 ± 0.44, = 0.27 ± 0.04). MeOH as solvent slightly reduces the propagation rate coefficient of HEMA compared to the bulk system, in contrast to the increase in the MEA value. Thus, the value of is higher in MeOH for MEA‐rich systems compared to bulk, with the effect of the solvent reduced as the HEMA content in the comonomer mixture is increased. Adding water as cosolvent significantly increases values for both monomers, with in MeOH/H2O higher than bulk values over the complete composition range. Furthermore, for 50% monomer in the solvent systems studied can be represented by the implicit penultimate unit model using a single pair of radical reactivity ratios. It is concluded that the strongest influence of hydrogen‐bonding solvents compared to bulk is on the homopropagation values, rather than on copolymerization parameters, and that the difference in relative reactivity of non‐functional and functional monomers in bulk and aqueous solution should be accounted for when studying emulsion copolymerization.

Kinetic analysis of continuous reaction data for RAFT and free radical copolymerization with acrylic and styrenic monomers

Free radical (FR) and Reversible Addition Fragmentation Chain Transfer (RAFT) copolymerization rates for styrenic monomers in bulk and aqueous reactions were accelerated by acrylic comonomers, whose own rates were both delayed and decreased. The effect was found with styrenics as low as 0.6% by mole, and is directly observable from Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP) data. Rapid radical transfer from acrylic to styrenic comonomer, through lower energy radical resonance stabilization in styrenics, was the suspected cause. FR and RAFT rates were equal, suggesting that FR termination controlled radical concentrations and rates. Despite strongly changing concentrations of initiator and comonomer radicals during reactions, the Quasi-Steady-State Approximation was demonstrated to hold. While rates were identical, molecular weights showed the characteristic increase with conversion for RAFT and decrease for FR. A new, generalized method for reactivity ratio determination was found and acceleration/deceleration behavior was consistently interpreted within a penultimate model.

Semiquantitative Approach for Polyester Characterization Using Matrix-Assisted Laser Desorption Ionization/Time-of-Flight Mass Spectrometry Approved by 1H NMR.

Matrix-assisted laser desorption ionization/time-of-flight (MALDI/ToF) mass spectrometry and 1H NMR were used for the structural investigation of isophthalic and maleic acid copolyesters with neopentyl glycol. Since both methods provided information on the ratio of incorporated acid components and terminating groups, results were compared and linear correlations (R2 = 0.96–0.98) could be found. This suggests that MALDI/ToF MS is a suitable tool for the semiquantitative characterization of polyester systems. For the isophthalic/maleic acid ratio, MALDI results yielded constantly lower values than 1H NMR, which was attributed to varying ionization efficiencies of homo- and copolyesters. Ratios of carboxylic and hydroxylic terminating groups, which are conventionally still measured by time consuming complex titrations, were measured with MALDI and 1H NMR and were in good agreement. Both methods either excluded or distinguished unreacted monomers in the polyester bulk in contrast to acid–base titrations where those monomers severely distort the results. Additional structural information could be gained including the observation of cyclic structures (MALDI), E/Z isomerism from maleic to fumaric acid, and the statistical distribution of the acid components within the polyester chain (1H NMR). While 1H NMR peak assignments have to be verified by 13C NMR and multidimensional techniques, MALDI/ToF MS provides a straightforward technique that can be applied to other polyester systems without major alterations.

Energetically significant nitrile⋯nitrile and unconventional C–H⋯π(nitrile) interactions in pyridine based Ni(II) and Zn(II) coordination compounds: Antiproliferative evaluation and theoretical studies

Two new coordination compounds viz. [Ni(2,6-PDC)(Hdmpz)(H2O)2]∙H2O (1) and [Zn(3-CNpy)2Cl2] (2) (2,6-PDC = 2,6-pyridinedicarboxylate, Hdmpz = 3,5-dimethylpyrazole, 3-CNpy = 3-cyanopyridine) have been synthesized and characterized using elemental analysis, thermogravimetric analysis, electronic, infrared spectroscopy and single crystal X-ray diffraction techniques. Crystal structure analyses reveal the presence of supramolecular assemblies involving interesting dimers with unconventional contacts in the compounds. DFT (Density Functional Theory) calculations on the supramolecular dimers in the crystal structure of 1 reveal that the sum of contributions of anion–π, π–π and other long range interactions due to the approximation of the bulk monomers is energetically significant. Molecular Electrostatic Potential (MEP) surface and Quantum Theory of Atoms in Molecules (QTAIM) analyses on the interesting supramolecular dimers of the crystal structures of 2 reveal the presence of unconventional anion⋯π contacts involving coordinated chlorido ligands and C–H⋯π(nitrile) interactions involving the π-system of the nitrile moiety of 3-cyanopyridine. Remarkably, Atoms in Molecules analysis also confirms the existence of energetically significant unconventional anti-parallel nitrile⋯nitrile interaction in the crystal structure of 2. Cell cytotoxicity of the compounds performed in Dalton's lymphoma (DL) malignant cancer cell line showed effective potency with negligible cytotoxicity in normal cells (~12%). It is interesting that compound 1has excellent cytotoxic potency with IC50 closer to cisplatin and can bind different biological targets with similar signalling pathways. Structure activity relationship (SAR) analyses of 1 and 2 based on pharmacophore modelling reveal that the molecular features associated with the structures of the compounds play important role in the biological activities.

Effective pair-potentials between droplets with end-grafted polymers within Pickering emulsions versus grafting-density, solvent quality and monomer concentration and phase diagrams architectures

The aim is a quantitative determination of the effective pair-potentials between droplets within Pickering emulsions of (oil-in-water or water-in-oil types), which are protected by end-grafted polymer-chains via (uncharged) big solid particles. This strong and irreversible grafting mode plays a fundamental role and rends the emulsions more stable, even in the absence of the charges. The droplets stabilization is very sensitive to the bath temperature that controls the solvent quality, the number of grafted-polymers per droplet (or grafting-density), and the concentration of monomers that float in the continuous phase (water or oil). The effective interaction between the hairy-droplets is a sum of two parts: the steric interaction coming from the excluded-volume forces, and the second is simply the usual van der Waals attraction. First, taking advantage of those results already derived using Renormalization Theory techniques, we determine the expression of the repulsive part of the overall pair-potentials, for all distances between the interacting hairy-droplets. Second, we study all the analytic properties of the obtained overall pair-potential, taking into account the solvent quality, the values of the bulk monomer concentration and the grafting-density. Third, these analytic properties enable us to classify the various shapes of the pair-potentials in space of the pertinent parameters. In particular, in any case (good and theta-solvents), we observe that, for high-grafting-densities (above some known critical value) or small monomer concentration (below some known critical value), the potentials exhibit an energy barrier that prevents the coalescence of the hairy-droplets. As remark, incidentally, the determined expressions of the pair-potentials are very similar to those of the DLVO potentials. Fourth, we draw the architectures of the phase diagrams in the (N,f)-plan, for dilute solutions, and in (f,Φ0)-plan, for semi-dilute solutions, where N, f and Φ0 denote the polymerization degree of the grafted-polymer-chains, their number per hairy-droplet and the monomer volume fraction, respectively. Finally, we discuss a link of the present work to experiment.

Kinetic study of alkyl methacrylate polymerization in nanoporous confinement over a broad temperature range

The effect of nanoconfinement on the free radical polymerization of ethyl methacrylate (EMA) and n-butyl-methacrylate (BMA) with di-tert-butyl peroxide (DtBP) initiator is investigated over a wide temperature range from 80 to 190 °C using differential scanning calorimetry. The effective rates are similar for the two bulk monomers although the BMA reacts approximately 11% faster at 95 °C. For nanoconfined cases, the initial reaction rate for monomer confined in the pores of controlled pore glass is enhanced, with larger effects observed in native pores compared to pores in which the native silanol was converted to trimethyl silyl. The onset of autoacceleration also occurs earlier under nanoconfinement, with decreases in both the conversion and the time required to reach autoacceleration, xgel and tgel, respectively, and larger changes for the native pores. The induction time follows Arrhenius behavior and increases under nanoconfinement. At polymerization temperatures above 160 °C, depropagation becomes important as the ceiling temperature is approached and seems to be more pronounced under nanoconfinement than in the bulk.

Synthesis of ‘living’ poly(2-dimethylaminoethyl methacrylate) and stimuli responsive/multifunctional block copolymers effective in fabrication of CdS ‘smart’ ‘Q-Particles’

Living poly[(2-dimethylamino)ethyl methacrylate] (PDMAEMA) has been synthesized by Atom Transfer Radical Polymerization (ATRP) of (2-dimethylamino)ethyl methacrylate in bulk at 30 °C using CuCl/N,N,N′,N″,N″-pentamethyldiethylenetriamine catalyst. Addition of catalytic amount of tricaprylylmethylammonium chloride (AQCl) keeps the deactivator cupric complex soluble throughout the polymerization resulting in controlled polymerization. The solubility of the charged copper complexes in bulk monomer is proposed through their entrapment within the ionic core of the reverse micelle like aggregates formed by AQCl, as observed from Cryo-TEM and dynamic light scattering analysis. An adventitious role of water molecules in respect of control over polymerization is noted when moist monomer or AQCl is used. Synthesized PDMAEMA molecules work efficiently as macroinitiators for the synthesis of different stimuli responsive, multifunctional di- or triblock copolymers through sequential polymerization. The diblock copolymer PDMAEMA-b-poly[di(ethyleneglycol) methyl ether methacrylate] stabilizes CdS quantum dots in aqueous medium which show stimuli dependent reversible switch between micelle ‘core-confined’ and ‘corona-embedded’ morphologies.

Two-arm PCL and PLLA macrophotoinitiators with benzoin end-functional groups by combination of ROP and click chemistry and their use in the synthesis of A2B2 type miktoarm star copolymers

Novel and well defined macrophotoinitiators with two-arm poly(ε−caprolactone) (PCL) and poly(l-lactide) (PLLA) chains bearing two benzoin photofunctionalities (BPI) at the connection point of the polymer chains have been synthesized by combination of ring opening polymerization (ROP) and click chemistry. Initially, dibromo end-functionalized two-arm PCL, (PCL)2-(Br)2, and PLLA, (PLLA)2-(Br)2, were synthesized by ROP of ε−caprolactone and l-lactide monomers in bulk, using 2,2-bis(bromomethyl)-1,3-propanediol as the initiator and stannous-2-ethylhexanoate, (Sn(Oct)2), as the catalyst. Then, the terminal bromines of the polymer arms were converted into azide groups with sodium azide (NaN3). Subsequently, well-defined two-arm PCL and PLLA macrophotoinitiators with benzoin end functional groups [(PCL)2-(BPI)2 and (PLLA)2-(BPI)2] were obtained from the click reaction between diazido end-functionalized (PCL)2-(N3)2 and (PLLA)2-(N3)2 polymers and an alkyne-terminated benzoin photoinitiator (BPI-alkyne) which was synthesized from benzoin and propargyl bromide. The 1H NMR, FT-IR, GPC, UV, and fluorescence spectroscopic studies revealed that two-arm poly(ε−caprolactone) and poly(l-lactide) having benzoin photofunctional groups bound to the linking point of the chains were obtained. These polymers were then used as macrophotoinitiators for the photoinduced free radical promoted cationic polymerization of cyclohexene oxide (CHO) monomer to synthesize A2B2 type miktoarm star copolymers comprised of PCL or PLLA as A blocks and PCHO as B blocks.

Installing Stable Molecular Chirality within the Walls of Periodic Mesoporous Organosilicas via Self-Assembly

The synthesis of highly ordered chiral periodic mesoporous organosilica (PMO) materials is described using a novel approach. Chiral dopants featuring removable chirality were combined with freely rotating bulk monomers, resulting in a bulk chiral material with handedness related to the chiral dopant. Once incorporated into the PMO, removal of the chiral-linker in the dopant is readily accomplished and occurs with complete preservation of the circular dichroism signal in the PMO material, whereas in the precursor molecule, this transformation would lead to a total loss of chirality. The chirality of the PMO material is retained even after prolonged hydrothermal treatment, indicating stable chirality induction within the walls of solid PMO.

Dependence of Propagation Rate Coefficients in Radical Polymerization on Solution Properties

The effect of solvents and monomer concentration on rate coefficients of propagation in radical polymerization has received tremendous interest during recent years, but a quantitative explanation and method of prediction of the medium effect is still missing. In this paper, it is shown that the thermodynamic formulation of the transition state theory is able to explain such effects almost quantitatively for a wide variety of monomers and solvents, including not only organic solvents but also less common solvents like ionic liquids or water, and monomers ranging from styrene to water‐soluble monomers like acrylic acid or N‐vinylformamide and also bulky monomers like isobornyl methacrylate. The medium effect is dictated by the activity coefficient of the monomer as well as by the ratio of the activity coefficients of the growing chain and the transition state. The solvent and concentration effects are, thus, a consequence of the degree of nonideality of the system. This interpretation based on the thermodynamics of real solutions offers for the first time a straightforward method to estimate the propagation rate coefficient of a given monomer in various solvents once the corresponding coefficient in bulk monomer is known. image

Synthesis of well-defined bisbenzoin end-functionalized poly(ε-caprolactone) macrophotoinitiator by combination of ROP and click chemistry and its use in the synthesis of star copolymers by photoinduced free radical promoted cationic polymerization

A new well-defined bisbenzoin group end-functionalized poly(ε-caprolactone) macrophotoinitiator (PCL-(PI)2) was synthesized by combination of ring opening polymerization (ROP) and click chemistry. The ROP of ε-CL monomer in bulk at 110 °C, by means of a hydroxyl functional initiator namely, 3-cyclohexene-1-methanol in conjunction with stannous-2-ethylhexanoate, (Sn(Oct)2), yielded a well-defined PCL with a cyclohexene end-chain group (PCL-CH). The bromination and subsequent azidation of the cyclohexene end-chain group gave bisazido functionalized poly(ε-caprolactone) (PCL-(N3)2). Separately, an acetylene functionalized benzoin photoinitiator (PI-alkyne) was synthesized by using benzoin and propargyl bromide. Then the click reaction between PCL-(N3)2 and PI-alkyne was performed by Cu(I) catalysis. The spectroscopic studies revealed that poly(ε-caprolactone) with bisbenzoin photoactive functional group at the chain end (PCL-(PI)2) with controlled chain length and low-polydispersity was obtained. This PCL-(PI)2 macrophotoinitiator was used as a precursor in photoinduced free radical promoted cationic polymerization to synthesize an AB2-type miktoarm star copolymer consisting of poly(ε-caprolactone) (PCL, as A block) and poly(cyclohexene oxide) (PCHO, as B block), namely PCL(PCHO)2.

Synthetic Biology for Cell-Free Biosynthesis: Fundamentals of Designing Novel In Vitro Multi-Enzyme Reaction Networks.

Cell-free biosynthesis in the form of in vitro multi-enzyme reaction networks or enzyme cascade reactions emerges as a promising tool to carry out complex catalysis in one-step, one-vessel settings. It combines the advantages of well-established in vitro biocatalysis with the power of multi-step in vivo pathways. Such cascades have been successfully applied to the synthesis of fine and bulk chemicals, monomers and complex polymers of chemical importance, and energy molecules from renewable resources as well as electricity. The scale of these initial attempts remains small, suggesting that more robust control of such systems and more efficient optimization are currently major bottlenecks. To this end, the very nature of enzyme cascade reactions as multi-membered systems requires novel approaches for implementation and optimization, some of which can be obtained from in vivo disciplines (such as pathway refactoring and DNA assembly), and some of which can be built on the unique, cell-free properties of cascade reactions (such as easy analytical access to all system intermediates to facilitate modeling).

Polythioethers by Thiol‐Ene Click Polyaddition of α,ω‐Alkylene Thiols

The straightforward synthesis of a series of poly(thioether)s by photoinduced thiol-ene click polyaddition of α,ω-alkylene thiols is reported. It is found that linear and telechelic poly(thioether)s can be directly obtained from α,ω-alkylene thiols with, for example, alkyl chain length of m = 1,2,3, and 9. The reaction proceeds without additives such as (radical) initiators or metal compounds and can simply be carried out by UV-irradiation of the bulk monomer or monomer solution. Ex situ kinetic studies reveal that the reaction proceeds by a typical a step-growth polyaddition mechanism. As the homologue series of poly(thioether)s are now synthetically accessible, new direct pathways to tailored poly(alkyl sulphoxide)s and poly(alkyl sulfone)s are now possible.