Vinyl Polymerization Research Articles

Synchronous Control of Chain Length/Sequence/Topology for Precision Synthesis of Cyclic Block Copolymers from Monomer Mixtures.

Precision synthesis of cyclic polymers with predictable molecular weight and low dispersity is a challenging task, particularly concerning cyclic polar vinyl polymers through a rapid chain-growth mechanism and without high dilution. Harder yet is the precision synthesis of cyclic block copolymers (cBCPs), ideally from comonomer mixtures. Here we report that Lewis pair polymerization (LPP) capable of thermodynamically and kinetically compounded sequence control successfully addressed this longstanding challenge. Thus, LPP of acrylate/methacrylate mixtures under ambient temperature and normal concentration conditions rapidly and selectively affords well-defined cBCPs with high molecular weight (Mn = 247 kg/mol) and low dispersity (Đ = 1.04) in one step. Such cBCPs have been characterized by multiple techniques, including direct structural observation by imaging.

Porous polymer thin film encapsulated sulfur nanoparticles on graphene via partial evaporation for high-performance lithium–sulfur batteries

Lithium–sulfur batteries, owing to their excellent advantages (including low cost and high theoretical energy density), might be the next-generation energy storage devices. However, the low S contents in their electrodes and the shuttling effect of soluble polysulfides can significantly deteriorate their capacities and cycle lives. Herein, we demonstrate a uniquely structured composite electrode, named porous polymerized vinyl acetate (p-PVAc) thin films, to break through the “trade-off” between the energy density and rate capability. S nanoparticles were encapsulated by porous p-PVAc layers and then anchored on graphene (p-PVAc/S/G), facilitating ion exchange and electron transfer during electrochemical operations. Consequently, p-PVAc/S/G delivered a high specific capacity of 719 mAh g−1 at 0.1 A g−1 and exceeded even 350 mAh g−1 at a high current density of 5 A g−1, whereas the average Coulombic efficiency was preserved to be higher than 98.50% when repeated for more than 300 cycles at 1 A g−1.

Preparation of Self-Healable and Spinnable Hydrogel by Dynamic Boronate Ester Bond from Hyperbranched Polyglycerol and Boronic Acid-Containing Polymer

Intrinsic self-healing hydrogel materials have been studied by many researchers owing to their excellent durability and high applicability in the biomedical field. Herein, we report a self-healing hydrogel containing dynamic boronate ester bonds. First, low-molecular-weight hyperbranched polyglycerol (LMPG), containing cis-1,2- or 1,3-diols, was synthesized by cationic ring-opening polymerization of glycidol initiated from citric acid. Second, 4-vinylphenyl boronic acid and acrylamide were co-polymerized in the LMPG-containing alkaline solution used for preparing the hydrogel. The composition of vinyl monomers, LMPG, and chemical cross-linker affects the gel-formation and self-healing properties of the hydrogel. Interestingly, the prepared hydrogel with specific composition exhibits excellent extensibility, resulting in 416-fold (41,600%) elongation. The formation of a reversible boronate ester bond by a diol of LMPG and boronic acid of vinyl polymer enables flexible fiber spinning process by reducing the drawing stress. After fiber fabrication is completed, the reversible bonds act as permanent multi-cross-point under absence of water, thereby giving a high tensile strength (128 MPa) to the hydrogel-based fiber.

Branched polymers through redox emulsion polymerization using peroxide monomer as the branching agent

AbstractRedox emulsion polymerization to branched vinyl polymers in the presence of 2‐(tert‐butylperoxy)ethyl methacrylate (BPEMA), ferrous sulfate, and sodium formaldehyde sulfoxylate (SFS) is reported in this paper. The peroxide monomer BPEMA containing alkyl peroxide was designed for high stability during preparation and storage. Nuclear magnetic resonance spectroscopy (NMR), Raman, and triple‐detection size‐exclusion chromatography (TD‐SEC) measurements were used to reveal the polymerization procedure and provide evidence of branching structure. In the case of polymerization at St100‐BPEMA1.0‐FeSO4 0.5‐SFS0.2, the molecular weight increased and decreased with conversion below and above 75% monomer conversion, respectively. The decreasing of molecular weight with monomer conversion came from the increased viscosity of the micelle, which makes it difficult for the formed macromolecules containing vinyl group to participate into polymerization. Finally, the molecular weight reached a value of Mn. SEC = 439,200 g/mol at 92.2% conversion. In addition, the Zimm branching factor, g', also decreased and increased with conversion below and above 60% conversion, respectively, and then the g' finally attends a value of 0.41, showing high degree of branching. Branched poly(methyl methacrylate) was also prepared through this strategy, showing a versatile approach to branched vinyl polymers.

Pd Nanoparticles-Loaded Vinyl Polymer Gels: Preparation, Structure and Catalysis

Four vinyl polymer gels (VPGs) were synthesized by free radical polymerization of divinylbenzene, ethane-1,2-diyl dimethacrylate, and copolymerization of divinylbenzene with styrene, and ethane-1,2-diyl dimethacrylate with methyl methacrylate, as supports for palladium nanoparticles. VPGs obtained from divinylbenzene and from divinylbenzene with styrene had spherical shapes while those obtained from ethane-1,2-diyl dimethacrylate and from ethane-1,2-diyl dimethacrylate with methyl methacrylate did not have any specific shapes. Pd(OAc)2 was impregnated onto VPGs and reduced to form Pd0 nanoparticles within VPGs. The structures of Pd0-loaded VPGs were analyzed by XRD, TEM, and nitrogen gas adsorption. Pd0-loaded VPGs had nanocrystals of Pd0 within and on the surface of the polymeric supports. Pd0/VPGs efficiently catalyzed the oxidation/disproportionation of benzyl alcohol into benzaldehyde/toluene, where activity and selectivity between benzaldehyde and toluene varied, depending on the structure of VPG and the weight percentage loading of Pd0. The catalysts were stable and Pd leaching to liquid phase did not occur. The catalysts were separated and reused for five times without any significant decrease in the catalytic activity.

Liquid‐crystalline behavior and thermal conductivity of vinyl polymers containing benzoxazole side groups

AbstractA series of methacrylamides containing benzoxazole (BO) mesogenic side groups and different lengths of alkyl units was synthesized in this study. A methacrylamide containing the n‐dodecyl group was selected as a suitable monomer to obtain beneficial thermally conductive polymeric materials because of its sufficient solubility in toluene in the subsequent radical polymerization and because of its liquid crystallinity. This methacrylamide led to a highly soluble polymer with film‐forming ability. The BO‐containing polymethacrylamide also exhibited liquid‐crystalline (LC) behavior during the heating and cooling processes. The cast film was kept at a slightly lower temperature than the clearing temperature and quenched to room temperature. This procedure afforded a film maintaining optical anisotropy at room temperature, implying that a frozen LC structure is maintained at room temperature. The quenched film also resulted in a significantly enhanced thermal conductivity (λ = 0.60 W m−1 K−1) without the aid of fillers and external fields, unlike the as‐cast counterpart without optical anisotropy. A polyacrylate containing a flexible long alkylene (C6) spacer between the main chains and a BO‐containing mesogenic side group was also investigated. The polyacrylate exhibited LC behavior during the heating and cooling processes over wide ranges. The polyacrylate film quenched from an established temperature, which contains a frozen LC structure, also exhibited a significantly enhanced λ value (0.63 W m−1 K−1) without fillers and external fields. Thus, the BO‐containing vinyl polymers studied in this work are promising candidates for novel heat‐releasing materials. © 2020 Society of Chemical Industry

Relationship between water permeability and physical characteristics of polyolefins, vinyl polymers, and polycarbonates

Diagrams of compatibility of water permeability with glass transition temperature, density, and cohesion energy are constructed. The computer program “Cascade”, INEOS RAS was used. Polyolefins, vinyl polymers, and polycarbonates were analyzed. Compatibility diagrams are constructed for the areas of lowest and highest water permeability for different classes of polymers. For polyolefins and vinyl polymers, the lowest water permeability is selected in the range from 0 to 100 barrer, and the highest water permeability is from 1000 to 2000 barrer. For polycarbonates, the intervals from 0 to 70 barrer and from 3000 to 7000 barrer are selected. These diagrams allow you to select polymers that meet the specified values of density, cohesion energy, glass transition temperature, and the onset of temperature of intense thermal degradation.

Highly efficient vinylic addition polymerization of 5-vinyl-2-norbornene using benzylic palladium complexes as precatalysts

A very small amount of a palladium benzylic complex as initiator brings about the vinylic addition polymerization of the reluctant 5-vinyl-2-norbornene.

Access to tough and transparent nanocomposites via Pickering emulsion polymerization using biocatalytic hybrid lignin nanoparticles as functional surfactants

Coating of lignin nanoparticles with chitosan and glucose oxidase allows for the green synthesis of acrylic and vinyl polymers in Pickering emulsions. The resulting dispersions offer a green route to tough composites equipped with antioxidant activity.

Methods for producing butyl acetate

Butyl acetate is a universal solvent widely used in various industries, such as the leather and pharmaceutical industries. The article describes the ways to obtain butyl acetate in various ways: in-line and continuous. The material balance of the production of this product is also given. Butyl acetate (acetic acid butyl ester) is the most common solvent in the production and use of paints and varnishes.Dissolves cellulose ethers, oils, fats, chlorinated rubbers, vinyl polymers, carbiol resins, etc. The addition of butyl acetate together with a small amount of butyl alcohol prevents whitening of the lacquer films. It is a fragrant substance that is part of fruit essences and perfume compositions. It is used in the tanning industry as tannin.

Connection of water permeability with a number of physical properties of polymers

Currently, methods for predicting the properties of polymers are very popular, since they simplify the work of synthetic chemists. Instead of lengthy and time-consuming experiments, many properties of polymers can be predicted in advance based on their chemical structure. Naturally, such tasks must be computerized so that the properties are predicted after the chemical structure of the repeating polymer unit is displayed on the display screen. This is the so-called direct task. The inverse problem is more complex and interesting. It consists in entering the intervals of the desired characteristics into the computer. Then computer synthesis of polymers possessing these characteristics are realized. The work consists in writing a computer program that allows the computer synthesis of polymers of different classes with specified intervals of water permeability. These classes include polyurethanes, polysulfones, polysulfides, polyethers and polyesters, polyamides, polyketones and polyethyrketones, polycarbonates, polyolefins, vinyl polymers, polystyrene, acrylic and methacrylic polymers. On the basis of this program, water permeability compatibility diagrams are constructed with various physical characteristics of polymers – glass transition temperature, temperature of the onset of intensive thermal degradation, cohesion energy, density, solubility parameter (Hildebrand parameter).

Effect of Rotaxane-Cross-link (2) Property of Cross-linked Polymers Synthesized using Low Molecular Weight Rotaxane Cross-linkers

We discuss on the effect of rotaxane-cross-link on the mechanical property (i.e. toughening) of the cross-linked polymers, in particular on the mobility effect of the rotaxane components, using [2]rotaxane cross-linkers having low molecular weight axles but not high molecular weight one as mentioned in the previous paper, to evaluate the function of the circumrotatory and flipping mobilities in comparison with the translating mobility of the wheel components at the cross-link points. Independent on the length of the axle component, the low molecular weight axle-containing rotaxane cross-linkers showed good power to strengthen the toughness of the cross-linked polymers. Meanwhile, [3]rotaxane cross-linkers having two crown ether wheels with two polymerizable vinyl groups worked as the excellent cross-linkers to contribute to the toughening of the cross-linked polymers, whereas the axle component had no direct bonding to the polymer chain, being different from that of [2]rotaxane cross-linker. In the latter half of this review, we dealt with macrocyclic cross-linkers which can accept polymer chains in their cavity to form rotaxane-type cross-link. 60-Membered macrocycle possessing two Pd(II) complex units in its cavity functioned as a rotaxane-type cross-linker by accepting two polymer chains possessing the coordinating sites to Pd(II). Cross-linker synthesized by linking two 30-membered macrocyclic Pd(II) complex also showed a similar ability to link two polymer chains to cross-linking.

Merging of cationic RAFT and radical RAFT polymerizations with ring-opening polymerizations for the synthesis of asymmetric ABCD type tetrablock copolymers in one pot

A new bifunctional and switchable RAFT agent and a mechanism switching strategy were proposed to control the cationic RAFT polymerization, radical RAFT polymerization and ring-opening polymerization of vinyl and cyclic ester monomers and to produce block copolymers.

Sequence-regulated vinyl polymers via iterative atom transfer radical additions and acyclic diene metathesis polymerization

Iterative ATRAs and ADMET polymerization enabled the synthesis of sequence-regulated vinyl polymers without statistical distribution of monomer compositions and sequences.

Bacterial Redox Potential Powers Controlled Radical Polymerization

Microbes employ a remarkably intricate electron transport system to extract energy from the environment. The respiratory cascade of bacteria culminates in the terminal transfer of electrons onto higher redox potential acceptors in the extracellular space. This general and inducible mechanism of electron efflux during normal bacterial proliferation leads to a characteristic fall in bulk redox potential (Eh), the degree of which is dependent on growth phase, the microbial taxa, and their physiology. Here, we show that the general reducing power of bacteria can be subverted to induce the abiotic production of a carbon-centered radical species for targeted bioorthogonal molecular synthesis. Using two species, Escherichia coli and Salmonella enterica serovar Typhimurium as model microbes, a common redox active aryldiazonium salt is employed to intervene in the terminal respiratory electron flow, affording radical production that is mediated by native redox-active molecular shuttles and active bacterial metabolism. The aryl radicals are harnessed to initiate and sustain a bioorthogonal controlled radical polymerization via reversible addition-fragmentation chain transfer (BacRAFT), yielding a synthetic extracellular matrix of "living" vinyl polymers with predetermined molecular weight and low dispersity. The ability to interface the ubiquitous reducing power of bacteria into synthetic materials design offers a new means for creating engineered living materials with promising adaptive and self-regenerative capabilities.

A Simple Photochemical Route to Hyperbranched Polymers by Using Photolatent Inimer

AbstractA novel and straightforward approach for the synthesis of hyperbranched polymers (HBPs) by photoinduced self‐condensing vinyl polymerization (SCVP) is explored. The SCVP is achieved using a divinyl monomer possessing photocleavable moiety in the inner structure, acting as both photoinitiator and inimer (photolatent inimer) in conjunction with methyl methacrylate (MMA) under UV irradiation. HBPs with different branching densities are successfully produced. Depending on the concentration of inimer and irradiation time, lightly branched, hyperbranched and cross‐linked polymers are formed. The described approach may lead to future directions of photopolymerization in various applications especially in bio related systems requiring highly branched structures without contamination of low‐molar mass photoinitiator fragments.

Grafting of Poly(2‐Oxazoline) Side Chains from Polyester Containing Oxazoline Units and Their Blends with Water Soluble Vinyl Polymers

AbstractTernary polycondensation of thiomalic acid (TMA), adipic acid (ADA), and 1,5‐pentanediol (PD) at 80 °C proceeds to give polyester having pendent mercapto groups. After the mercapto groups are consumed quantitatively by a Michael addition with 2‐isopropenyl‐2‐oxazoline (IPOx) to create an initiation point for grafting, successive additions of methyl triflate (MeOTf) and 2‐oxazoline allow ring‐opening polymerization of 2‐oxazoline from the IPOx unit to give a graft copolymer with a Mn of 2.2 × 104 ‐ 3.7 × 104 and an molecular dispersity index (Mw/Mn = 1.9–2.6). The synthesized polyester‐based graft copolymer is water‐soluble and forms transparent blend films with poly(vinyl alcohol) (PVA) and poly(N‐isopropy acrylamide) (PNIPAM) using solvent cast methods. Differential scanning calorimetry measurements show that blends with PVA (<30% of the graft copolymer) show a single Tgs over the whole composition range. All scans for the blends with PNIPAM have a single Tgs that is between those of the parent polymers indicating that the graft copolymer shows excellent miscibility with PNIPAM, although the parent polyester, poly(TMA‐alt‐PD)‐co‐poly (ADA‐alt‐PD) does not exhibit such miscibility.

Biobased Polymers via Radical Homopolymerization and Copolymerization of a Series of Terpenoid-Derived Conjugated Dienes with exo-Methylene and 6-Membered Ring.

A series of exo-methylene 6-membered ring conjugated dienes, which are directly or indirectly obtained from terpenoids, such as β-phellandrene, carvone, piperitone, and verbenone, were radically polymerized. Although their radical homopolymerizations were very slow, radical copolymerizations proceeded well with various common vinyl monomers, such as methyl acrylate (MA), acrylonitrile (AN), methyl methacrylate (MMA), and styrene (St), resulting in copolymers with comparable incorporation ratios of bio-based cyclic conjugated monomer units ranging from 40 to 60 mol% at a 1:1 feed ratio. The monomer reactivity ratios when using AN as a comonomer were close to 0, whereas those with St were approximately 0.5 to 1, indicating that these diene monomers can be considered electron-rich monomers. Reversible addition fragmentation chain-transfer (RAFT) copolymerizations with MA, AN, MMA, and St were all successful when using S-cumyl-S’-butyl trithiocarbonate (CBTC) as the RAFT agent resulting in copolymers with controlled molecular weights. The copolymers obtained with AN, MMA, or St showed glass transition temperatures (Tg) similar to those of common vinyl polymers (Tg ~ 100 °C), indicating that biobased cyclic structures were successfully incorporated into commodity polymers without losing good thermal properties.

Laboratory analyses of Kaolinite stabilized by vinyl polymers with different monomer types

The geotechnical behavior of a mixture of kaolinite and vinyl polymers with different monomer types was investigated using a series of laboratory tests. Three polymers were selected for chemical treating including synthesized poly(styrene-co-butyl acrylate) and poly(methyl methacrylate–co-butyl acrylate), and one commercial polyvinyl acetate. All these polymers were chosen to have a similar glass transition temperature (Tg). A series of laboratory tests were conducted on the prepared samples, including Atterberg limits, unconfined compressive strength, direct shear, swelling potential, oedometer, triaxial tests, and scanning electron microscopy observation. The results showed changes in the soil microstructures and considerable improvement in shear strength parameters of clay with all monomer types. Also, the highest strength was obtained in the stabilized samples with polyvinyl acetate among three stabilizers. Conversely, the swelling parameters of the polyvinyl acetate stabilized soil increased compared to the unstabilized soil. Finally, the stabilized samples with poly(methyl methacrylate-co-butyl acrylate) demonstrated better performance in reducing the swelling and increasing the strength properties of soil.

Hyperbranched Bisphosphonate-Functional Polymers via Self-Condensing Vinyl Polymerization and Postpolymerization Multicomponent Reactions.

The synthesis of hyperbranched aminobisphosphonic acid polymers via reversible addition-fragmentation chain transfer (RAFT) self-condensing vinyl polymerization is reported. A novel acrylamide-functional chain transfer monomer is synthesized and characterized by 1 H and 13 C NMR spectroscopy, elemental analysis, and mass spectrometry. The monomer is subsequently copolymerized with an acrylamide monomer bearing a pendent amine group to create hyperbranched amine-functional polymers with degrees of branching dictated by changing the reaction stoichiometry. The aminobisphosphonate functional group is introduced via a 3-component Kabachnik-Fields reaction. An alternate functionalization of the amine polymers to create acid-degradable imine hydrogels is also employed. This work demonstrates the application of multicomponent reactions to RAFT-derived hyperbranched polymers and provides a new route to previously inaccessible polymers.