Vinyl Polymerization Research Articles

100th Anniversary of Macromolecular Science Viewpoint: Degradable Polymers from Radical Ring-Opening Polymerization: Latest Advances, New Directions, and Ongoing Challenges.

Radical ring-opening polymerization (rROP) allows facile incorporation of labile groups (e.g., ester) into the main chain of vinyl polymers to obtain (bio)degradable materials. rROP has focused a lot of attention especially since the advent of reversible deactivation radical polymerization (RDRP) techniques and is still incredibly moving forward, as attested by the numerous achievements in terms of monomer synthesis, macromolecular engineering, and potential biomedical applications of the resulting degradable polymers. In the present Viewpoint, we will cover the latest progress made in rROP in the last ∼5 years, such as its recent directions, its remaining limitations, and the ongoing challenges. More specifically, this will be achieved through the three different classes of monomers that recently caught most of the attention: cyclic ketene acetals (CKA), thionolactones, and macrocyclic monomers.

Evaluation of polymer/bentonite synergy on the properties of aqueous drilling fluids for high-temperature and high-pressure oil wells

The increasing demand for energy sources has led to oil field exploration under inhospitable conditions, where non-aqueous drilling fluids are commonly used due their physical and chemical stability. However, they exhibit a number of environmental constraints and the cuttings produced require expensive treatments before disposal. Aqueous drilling fluids are currently less thermally resistant and generally entail the use of chromium lignosulfonate as clay dispersant, which provides stability to rheological properties and filtration control under high temperature and high pressure (HTHP). This study elucidates the role played by synergic effect of a novel eco-friendly high-performance water-based drilling fluid using bentonite and vinyl polymers (polyvinylpyrrolidone (PVP) and partially hydrolyzed polyacrylamide (PHPA)) as the main constituents. Filtration and rheological properties of the drilling fluids were determined on a HTHP filtration system and on a rotational viscometer, respectively. Systems using high molar mass PVP (HMM PVP) showed higher values for viscosity, gel strength and yield stress, due to promotion of flocculation. On the other hand, dispersed systems were obtained using low molar mass PVP (LMM PVP), through ion-dipole interactions between PVP and clay particles. Dispersed systems provided stable rheological parameters over the entire range of temperature and pressure studied (up to around 120 °C and 3450 kPa). Linear clay swelling tests showed that LMM PVP and water had similar profiles, promoting clay dispersion. Profitable low filtrate volumes (12 mL) were obtained for PVP-based drilling fluids in conditions where non-aqueous fluids are currently applied.

A one pot one step combined radical and ring-opening route for the dual functionalization of starch in aqueous medium

Starch based materials are attractive bio-based alternative to fully synthetic polymers. Native starch has however limited thermoprocessability and properties and must be modified. In order to improve the properties of starch-graft-poly(butyl-acrylate-co-styrene) copolymers via a process as green as possible, we report herein a new method for the dual functionalization of the polysaccharide via a one pot one step reaction in aqueous medium combining free radical polymerizations and ring-opening chemistry. Poly(butyl acrylate) or poly(butyl acrylate-co-styrene) (ca. 60 000 g/mol) and oligo(ε-caprolactone) were grafted on starch with a grafting percentage up to 75 %. The copolymers show two glass transition temperatures: one around 55−60 °C related to starch and a second attributed to the grafted vinyl polymers, from −46 °C to 20 °C depending on butyl acrylate/styrene ratio. The resulting dual functionalized materials exhibit excellent mechanical properties, with elongation at break in the range 20–210 %, while single functionalized starch shows less than 5 %.

100th Anniversary of Macromolecular Science Viewpoint: The Past, Present, and Future of Stereocontrolled Vinyl Polymerization.

The thermomechanical properties exhibited by synthetic macromolecules can be directly linked to their tacticity, or the relative stereochemistry of repeat units. The development of stereoselective coordination-insertion polymerization, for example, led to the discovery of isotactic polypropylene, now one of the most widely produced commodity plastics in the world. Widespread interest in controlling polymer tacticity has led to a variety of stereoselective polymerization methodologies; however, this area of polymer science has lagged behind when compared to the ability to control molecular weight, dispersity, and composition. Despite decades of advancements, many stereoregular vinyl polymers remain unknown, particularly those comprised of polar functionality or derived from renewable resources. This Viewpoint provides an overview of recent developments in stereocontrolled polymerization, with an emphasis on propagation mechanism, and highlights successes, limitations, and future challenges for continued innovation.

Multifactor Control of Vinyl Monomer Sequence, Molecular Weight, and Tacticity via Iterative Radical Additions and Olefin Metathesis Reactions.

Monomer sequence control in terms of a single monomer unit, particularly in vinyl polymers, is one of the largest challenges in polymer chemistry. Furthermore, multifactor control of monomer sequence, molecular weight, and stereoregularity is an ultimate goal. In this work, we propose a strategy to prepare C-C main-chain sequence-regulated polymers with controlled molecular weights from vinyl monomers via a combination of iterative atom transfer radical additions and olefin metathesis reactions. This strategy enabled the synthesis of sequence-regulated polymers with exact styrene-acrylate-styrene sequences in the C-C main chains, controlled molecular weights of up to 104, and stereoregularities varying with syndiotacticity, isotacticity, and heterotacticity. The utility of this strategy is further demonstrated by formation of block copolymers consisting of sequence-regulated vinyl polymer segments by combining living ROMP of norbornene derivatives.

Push-Out Test of Steel-Concrete-Steel Composite Section for Pre-Installation and Post-Installation Techniques of Shear Connectors

Composite steel-concrete sections have a broad benefit through increasing structural strength as well as minimizing the self-loads. All past researches were concerned with pre-installed shear connectors (PRSC) in the manufacturing of composite sections. A new fabrication technique for steel-concrete-steel composite sections were presented in the current study by the post-installation shear connectors (POSC) passed-through an embedded polymerizing vinyl chloride (PVC) pipes. The performance of normal strength concrete prisms with a specified strength of 32 MPa connected to square steel tubes (SST) was investigated. Six specimens were fabricated in both methodologies, PRSC and POSC were experimentally tested by Push-out test. The spacing of the shear connectors was changed for every two specimens fabricated in two different ways in order to obtain a full behavioral view. However, POSC does not have full-bond to concrete prisms, the test revealed a comparable strength of POSC specimens. The test shows a slight increase in the ultimate strength of PRSC specimens by (12.11, 11.19, and 9.45) % than POSC specimens for 100mm, 150mm, and 200mm spaced shear connectors.

Progress and Perspectives Beyond Traditional RAFT Polymerization.

The development of advanced materials based on well‐defined polymeric architectures is proving to be a highly prosperous research direction across both industry and academia. Controlled radical polymerization techniques are receiving unprecedented attention, with reversible‐deactivation chain growth procedures now routinely leveraged to prepare exquisitely precise polymer products. Reversible addition‐fragmentation chain transfer (RAFT) polymerization is a powerful protocol within this domain, where the unique chemistry of thiocarbonylthio (TCT) compounds can be harnessed to control radical chain growth of vinyl polymers. With the intense recent focus on RAFT, new strategies for initiation and external control have emerged that are paving the way for preparing well‐defined polymers for demanding applications. In this work, the cutting‐edge innovations in RAFT that are opening up this technique to a broader suite of materials researchers are explored. Emerging strategies for activating TCTs are surveyed, which are providing access into traditionally challenging environments for reversible‐deactivation radical polymerization. The latest advances and future perspectives in applying RAFT‐derived polymers are also shared, with the goal to convey the rich potential of RAFT for an ever‐expanding range of high‐performance applications.

Distributions of Molecular Weights and 3D Sizes of Hyperbranched Polymers Formed in Batch Self‐Condensing Vinyl Polymerization

AbstractIt is known that the step polymerization of AB2‐type monomer leads to form random hyperbranched architecture, irrespective of the reactivity of the second B group. On the other hand, the hyperbranched structure formed in the self‐condensing vinyl polymerization of AB* monomer is now shown to be nonrandom because of the persistent history‐dependent connection through the A* group. The molecular weight distribution deviates from that of the random branched polymers. On the other hand, the nonrandom effect on the 3D architecture is rather small, and the expected g‐ratio of the unperturbed mean‐square radius of gyration 〈s2〉0 of the branched molecule to that of a linear molecule for a given number k of branch points agrees well with the Zimm–Stockmayer equation that assumes random branching of primary chains having the most probable distribution.

Exploring Vinyl Polymers as Soft Carbon Precursors for M-Ion (M = Na, Li) Batteries and Hybrid Capacitors

The viability of the sodium-ion batteries as a post-lithium storage technology is strongly tied to the development of high-performance carbonaceous anode materials. This requires screening novel precursors, and tuning their electrochemical properties. Soft carbons as promising anode materials, not only for batteries, but also in hybrid capacitors, have drawn great attention, due to safe operation voltage and high-power properties. Herein, several vinyl polymer-derived soft carbons have been prepared via pyrolysis, and their physicochemical and sodium storage properties have been evaluated. According to the obtained results, vinyl polymers are a promising source for preparation of soft carbon anode materials for sodium-ion battery application. In addition, their applicability towards Li-ion battery and hybrid capacitors (e.g., Li ion capacitors, LICs) has been examined. This work not only contrasts the carbonization products of these polymers with relevant physicochemical characterization, but also screens potential precursors for soft carbons with interesting alkali metal-ion (e.g., Na or Li, with an emphasis on Na) storage properties. This can stimulate further research to tune and improve the electrochemical properties of the soft carbons for energy storage applications.

Unimolecularly thick monosheets of vinyl polymers fabricated in metal\u2013organic frameworks

Polymers with two-dimensional (2D) network topologies are currently gaining significant attention due to their unique properties that originate from their regulated conformations. However, in contrast to conventional 1D- and 3D-networked macromolecules, the synthesis of such 2D networks provides challenges for polymer chemists because of the nature of the networking polymerisation reaction, which occurs in a spatially random fashion when conventional solution-phase synthesis is performed. Here we report a versatile synthesis of polymeric monosheets with unimolecularly thick networking architectures by exploiting the 2D nanospaces of metal–organic frameworks (MOFs) as reaction templates. Crosslinking radical polymerisation in the 2D nanospaces of pillared-layer-type MOFs affords monosheets of typical vinyl polymers and can be carried out on the gram scale. Remarkably, the prepared polymer monosheets are highly soluble in organic solvents and show atypical thermal and rheological properties that result from their 2D-regulated conformations that cannot be adopted by their 1D or 3D analogues.

Ab Initio Quantitative Prediction of Tacticity in Radical Polymerization of Poly(methyl methacrylate) by a Molecular Simulation Technique with the Conformation Indexing for Multiple Transition States

Free-radical polymerization is a critical route for generating vinyl polymers owing to its versatility and productivity, while the realization of stereospecific propagation has been considered very difficult and demanding. Therefore, a concrete investigation on the mechanism of tacticity obtained in radical polymerization is urgent. Experimentally, tacticity of poly(methyl methacrylate) produced by radical polymerization in bulk was reported to be syndiotactic and temperature-dependent. In this study, we intended to rationalize those behaviors on the microscopic scale via density functional theory calculations and a hybrid Monte Carlo/molecular dynamics simulation [Red Moon methodology]. We devised a unique conformation indexing based on the multidimensional conformational analysis and obtained as many as 576 transition state conformations for the propagation reaction. Boltzmann factors of the 576 conformations implied the overall higher stability of pro-racemo conformations than pro-meso ones and, in addition, the more syndiotactic tendency at low temperature. By the Red Moon simulations utilizing the energy barriers of those conformations, we successfully simulated the propagation reaction process and achieved quantitative agreement of the product tacticity. These results exhibit the validity of our ab initio molecular simulation procedure with the conformation indexing to realize quantitative analysis of the selectivity of reactions.

In vivo study of 8-OHdG as a biomarker DNA damage by combining the exposure of nonyl phenol and copper using ELISA technique

Nonylphenol (NP) is an environmental contaminants produced by alkylphenol ethoxylates which is non-ionic surfactant. NP has recently been found in foods derived from antioxidant hydrolysis of tris nonylphenyl phosphite which is used as a heat stabilizer in the manufacture of polymer food packaging materials, such as styrene, vinyl polymer, rubber and polyolefins. Copper (Cu) is a redox metal which in the normal dose is an essential mineral that needed by the body, but excess Cu will cause damage in some organs. Both NP and Cu can produce OH radicals in the body, which means that OH radicals will potentially attack DNA and thus form a biomarker of DNA damage such as 8-OHdG. This study of DNA adducts of 8-OHdG formation due to NP as a xenobiotic and Cu as metals. In this research, the eight-month-old Sprague Dawly rats weighing 200 −300 g were randomly divided into three groups (Control, Cu, NP, and NP + Cu, n = 5). The tested rats were orally treated every 24 h for 28 days. Finally, the collected plasma was tested using ELISA technique to study the 8-OHdG content. Based on the results, it was shown that both NP and Cu metals could trigger the formation of 8-OHdG. The highest concentration of 8-OHdG formed was the exposure group of NP + Cu in day 14 with a concentration of 1.3412 ng/mL.

Adhesive Materials Based on Modified Low Molecular Copolymer of Ethylene with Vinyl Acetate

Adhesive material based on low molecular copolymer of ethylene with vinyl acetate and polymer complex synthesized by radical polymerization of acrylic acid in the presence of e-caprolactam was developed. The compound of the adhesive was optimized, and the influence of composition and concentration of the complex, in addition to fine-grained filler (chalk), on the stickiness and adhesive strength of compositions to substrates of various natures being studied. It was shown that the adhesive characteristics of the developed adhesive compositions are superior to the corresponding indices of a composition based on low molecular polyethylene, which allows recommending them for application as construction mastic resins and as a base for label pastes and compounds for spraying on polymer films.

Thioester-Functional Polyacrylamides: Rapid Selective Backbone Degradation Triggers Solubility Switch Based on Aqueous Lower Critical Solution Temperature/Upper Critical Solution Temperature

Radical ring-opening polymerization is a clever strategy to incorporate cleavable linkages into otherwise nondegradable vinyl polymers. However, conventional systems suffer from slow copolymerizati...

Unique Self-Assembly of Sequence-Controlled Amino Acid Derived Vinyl Polymer with Gradient Thermoresponsiveness along a Chain.

A novel water-soluble amino acid derived vinyl polymer whose block sequence was designed to achieve a gradient thermoresponsiveness along a chain was accurately prepared through an ultrarapid reversible addition-fragmentation chain-transfer polymerization. The polymer exhibited unique temperature-regulated self-assembly in water, leading to multiple nanostructural transformations including disassembly-to-ordered and ordered-to-ordered transitions. The morphologies were drastically changed by heating the solution from 4 °C (soluble form) to 20 °C (spherical micelle) to 70 °C (vesicle). Moreover, such transitions exhibited hysteresis upon cooling, namely, from 70 °C (vesicle) to 20 °C (wormlike micelle) to 4 °C (soluble form). In this polymer system, the specific monomer sequence contributed to the self-assembly behavior. These findings provide significant insight into the design of new thermoresponsive nanomaterials with potential applications in biomedical chemistry.

Dial in your dispersity.

One can combine two distinct chain-transfer agents to tune the dispersity of vinyl polymers. The polymer chains remain living and can be transformed into diblock copolymers.

Monte Carlo Simulation on the Ternary Self-Condensing Vinyl Polymerization System with Semi-Batch Process

A Monte Carlo simulation on the ternary self-condensing vinyl polymerization system under the semi-batch mode is presented, where reactants are composed of comonomers (inimers and monomers) and multi-functionality core initiators. For the semi-batch process in the system, we mainly consider the influence of three feeding ways on the average polymeric quantities (weight-average molecular weight and polydispersity index) of hyperbranched polymers, where core initiators and comonomers are fed into the reactor at different time (or equivalently, at different conversions of vinyl group). As expected, the semi-batch process has a significant effect on the average properties of polymers, and therefore the feeding schedule can be predetermined to prepare polymers with desired properties.

Advancements in Soft-Tissue Prosthetics Part B: The Chemistry of Imitating Life.

Each year, congenital defects, trauma or cancer often results in considerable physical disfigurement for many people worldwide. This adversely impacts their psychological, social and economic outlook, leading to poor life experiences and negative health outcomes. In many cases of soft tissue disfigurement, highly personalized prostheses are available to restore both aesthetics and function. As discussed in part A of this review, key to the success of any soft tissue prosthetic is the fundamental properties of the materials. This determines the maximum attainable level of aesthetics, attachment mechanisms, fabrication complexity, cost, and robustness. Since the early-mid 20th century, polymers have completely replaced natural materials in prosthetics, with advances in both material properties and fabrication techniques leading to significantly improved capabilities. In part A, we discussed the history of polymers in prosthetics, their ideal properties, and the application of polymers in prostheses for the ear, nose, eye, breast and finger. We also reviewed the latest developments in advanced manufacturing and 3D printing, including different fabrication technologies and new and upcoming materials. In this review, Part B, we detail the chemistry of the most commonly used synthetic polymers in soft tissue prosthetics; silicone, acrylic resin, vinyl polymer, and polyurethane elastomer. For each polymer, we briefly discuss their history before detailing their chemistry and fabrication processes. We also discuss degradation of the polymer in the context of their application in prosthetics, including time and weathering, the impact of skin secretions, microbial growth and cleaning and disinfecting. Although advanced manufacturing promises new fabrication capabilities using exotic synthetic polymers with programmable material properties, silicones and acrylics remain the most commonly used materials in prosthetics today. As research in this field progresses, development of new variations and fabrication techniques based on these synthetic polymers will lead to even better and more robust soft tissue prosthetics, with improved life-like aesthetics and lower cost manufacturing.

Relaxation behavior of poly(diisopropyl fumarate) including no methylene spacer in the main chain

Poly(diisopropyl fumarate) (PDiPF) has dynamic mechanical properties different from the relaxation processes of conventional vinyl polymers, due to the absence of a methylene spacer in the main chain. In this study, we investigated the relaxation behavior of PDiPF using dielectric spectroscopy (DS), differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS), and dynamic mechanical analysis (DMA). We have demonstrated that the β relaxation of PDiPF has unusual characteristics originating from the absence of a methylene spacer; for example, the β relaxation of PDiPF follows the Vogel–Fulcher–Tammann (VFT) equation, causes a clear step in the DSC curve, and enhances the microscopic packing of the polymer chains in the solid state. These β relaxation behaviors of PDiPF reflect the enlarged cooperative rearranging region (CRR).

3D-printed face protective shield in interventional radiology: Evaluation of an immediate solution in the era of COVID-19 pandemic

PurposeThe purpose of this study was to report the clinical evaluation of a 3D-printed protective face shield designed to protect interventional radiologists from droplet transmission of the SARS-Cov-2. Materials and methodsA protective face shield consisting in a standard transparent polymerizing vinyl chloride (PVC) sheet was built using commercially available 3D printers. The 3D-printed face shield was evaluated in 31 interventional procedures in terms of ability to perform the assigned intervention as usual, quality of visual comfort and tolerance using a Likert scale (from 1, as very good to 5, as extremely poor). ResultsThe mean rating for ability to perform the assigned intervention as usual was 1.7±0.8 (SD) (range: 1–4). The mean visual tolerance rating was 1.6±0.7 (SD) (range: 1–4). The mean tolerability rating was 1.4±0.7 (SD) (range: 1–3). ConclusionThe 3D-printed protective face shield is well accepted in various interventions. It may become an additional option for protection of interventional radiologists.