Conventional Radical Research Articles

Comparison of Safety and Short-term Efficacy Among Conventional Radical Surgery, Portal Vein Reconstruction and Hepatic Artery Reconstruction on Hilar Cholangiocarcinoma

Comparison of Safety and Short-term Efficacy Among Conventional Radical Surgery, Portal Vein Reconstruction and Hepatic Artery Reconstruction on Hilar Cholangiocarcinoma

Polystyrene-Based Vitrimers: Inexpensive and Recyclable Thermosets

We report a straightforward and scalable method for the generation of polystyrene-based vinylogous urethane vitrimers using conventional radical polymerization. The copolymerization of the commerci...

Reduced port laparoscopic radical nephrectomy using an umbilical zigzag skin incision for renal cell carcinoma

Reduced port laparoscopic radical nephrectomy (RPLRN) is an equivalent approach to conventional laparoscopic radical nephrectomy (LRN). In LRN, one wound generally needs to be extended for specimen extraction; therefore, some ingenuity is needed to achieve a good cosmetic outcome. We herein describe our initial experience of RPLRN using an umbilical zigzag skin incision for renal cell carcinoma (RCC). A 64-year-old female [body mass index (BMI): 20.0kg/m2] was diagnosed with right RCC, which was 35mm in diameter (clinical T1aN0M0). Case 2: a 68-year-old male (BMI: 23.2kg/m2) was diagnosed with right RCC, which was 58mm in diameter (clinical T1bN0M1), and perinephric fat was relatively thick. The procedure was safely completed in both cases. Total operative times, pneumoperitoneal times, and estimated blood loss in Case 1 and 2 were 90 and 145min, 49 and 90min, and 5 and 80ml, respectively, and the times required to construct umbilical ports and close umbilical wounds were 8 and 9min and 33 and 46min, respectively. In Case 1, the specimen was easily extracted without the extension of the umbilical skin incision, whereas it was extended by an additional 2cm in Case 2. The umbilical wound was inconspicuous in both cases. RPLRN using an umbilical zigzag skin incision for RCC was safely performed without complications, and clashing between instruments was minimized. The high level of cosmesis is advantageous and an umbilical zigzag skin incision may contribute to more widespread use of RPLRN for RCC; however, further studies on long-term oncological outcomes are needed.

Modified Starch as a Filter Controller in Water-Based Drilling Fluids.

Herein, the effectiveness of an itaconic acid (IA) graft copolymer on native corn starch (NCS) as a filter control agent in fresh water-based drilling fluids (WBDFs) was evaluated. The copolymer (S-g-IA_APS) was synthesized by conventional radical dispersion polymerization using the redox initiation system (NH4)2S2O8/NaHSO3. The modification of the starches was verified by volumetry, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Then, three WBDFs were formulated in which only the added polymer (NCS, S-g-IA_APS, and a commercial starch (CPS)) was varied to control the fluid losses. The physico-chemical, rheological, and filtering properties of the formulated systems were evaluated in terms of density (ρ), pH, plastic viscosity (µp), apparent viscosity (µa), yield point (Yp), gel strength (Rg), and filtrated volume (VAPI). In order to evaluate the resistance to temperature and contaminants of the WBDFs, they were subjected to high pressure and high temperature filtering (VHPHT). The filter control agents were also subjected to aging and contamination with cement and salt. The S-g-IA_APS addition improved the filtering behavior at a high pressure and temperature by 38%.

Poly(amidoxime) ligand derived from waste palm fiber for the removal of heavy metals from electroplating wastewater.

A waste material known as palm oil empty fruit bunch (EFB) is used as a source of cellulose for the development of polymeric materials for the removal of metal ions from industrial wastewater. A poly(acrylonitrile)-grafted palm cellulose copolymer was synthesized by a conventional free radical initiating process followed by synthesis of a poly(amidoxime) ligand by oximation reaction. The resulting products were characterized by FT-IR, FE-SEM, EDX, TGA, DSC, and XPS. The poly(amidoxime) ligand was used to coordinate with and extract a series of transition metal ions from water samples. The binding capacity (qe) of the ligand with the metal ions such as copper, iron, cobalt, nickel, and lead were 260, 210, 168, 172, and 272 mg g-1, respectively at pH 6. The adsorption process followed the pseudo-first-order kinetic model (R2 > 0.99) and as well as the Freundlich isotherm model (R2 > 0.99) indicating the occurrence of a multi-layer adsorption process in the amidoxime ligand adsorbent. Results from reusability studies show that the ligand can be recycled for at least 10 cycles without any significant losses to its initial adsorption capacity. The synthesized polymeric ligand was shown to absorb heavy metals from electroplating wastewater with up to 95% efficiency.

Polymerization with Borane Chemistry. Tributylborane/p-Quinone System as a New Method of Reversible-Deactivation Radical Copolymerization for Styrene and Methyl Acrylate

We report a reversible-deactivation radical copolymerization of styrene and methyl acrylate in the presence of tributylborane and different p-quinones. p-Quinones, such as 1,4-naphthoquinone, 2,3-dimethyl-1,4-benzoquinone, 2,5-ditert-1,4-butylbenzoquinone, and duroquinone, with addition of a catalytic amount of tributylborane, allow for the control over styrene/methyl acrylate copolymerization. The process proceeds in a controlled manner via a reversible homolytic dissociation of the active macromolecules with terminal aryloxyboron-groups. The rate of styrene/methyl acrylate copolymerization depends on the inhibition constants of quinones. The molecular weight and molecular weight distribution of copolymers are directly dependent on the inhibitory abilities of the quinones. 1,4-Naphthoquinone and 2,3-dimethyl-1,4-benzoquinone act as the most effective mediators of chain propagation. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) results showed that the macromolecules contained internal fragments of p-quinone. Also, of the terminal aryloxyboron-groups were detected in the mass spectra. On realization of the “living” mechanism of copolymerization, the structure of copolymers obtained at high conversions can be considered as similar to the gradient structure. Stereo-regularity of the copolymers differed from the conventional radical copolymerization. The glass-transition temperature (Tg) of the gradient copolymer differed from Tg of the random compositional heterogeneous copolymer. The effect of the macromolecular structure on the mechanical properties of the copolymers was studied.

Merging New Organoborane Chemistry with Living Radical Polymerization

In this issue of Cell Reports Physical Science, Pan and co-workers synthesize alkylcatecholboranes that can be oxidized by oxygen to drive the release of carbon-centered radicals for initiating reversible addition-fragmentation chain transfer (RAFT) polymerization. These organoboranes can slowly decompose to radicals that enable RAFT polymerization with exceptional control yielding ultra-high molecular weight (UHMW) polymers.

α-Functionalization of Imines via Visible Light Photoredox Catalysis

The innate electrophilicity of imine building blocks has been exploited in organic synthetic chemistry for decades. Inspired by the resurgence in photocatalysis, imine reactivity has now been redesigned through the generation of unconventional and versatile radical intermediates under mild reaction conditions. While novel photocatalytic approaches have broadened the range and applicability of conventional radical additions to imine acceptors, the possibility to use these imines as latent nucleophiles via single-electron reduction has also been uncovered. Thus, multiple research programs have converged on this issue, delivering creative and practical strategies to achieve racemic and asymmetric α-functionalizations of imines under visible light photoredox catalysis.

Controlled fabrication of polymer nanofibers via conventional free radical polymerization using diurea xerogel fibers as the templates

Polymer nanofibers with smooth surface were fabricated via conventional free radical polymerization of diurea type supramolecular gel fibers in cyclohexane. As the solvent polarity by using toluene increased, the product yield and fiber size increased, while the fibers changed from smooth to rough, together with more and more free particles. In the presence of polar methacrylic acid, both rough fibers and free particles were obtained when polymerized in cyclohexane. When nonpolar 2-(perfluoro-3-methylbutyl)ethyl acrylate (R-3420) was used, only polymer fibers with very smooth surface were formed. The morphologies of fluoropolymer samples changed from fibers to particles, while the fiber surface became rougher and rougher, as more and more ethanol was used. The hydrophobic fluoropolymer sample could extract toluene from water-toluene two-phase system. Compared with granular fluoropolymer samples, fibrous fluoropolymer samples displayed higher specific surface area and higher swelling ratio in toluene, and required a shorter time for toluene to flow through them.

Poor Solvents Improve Yield of Grafting-Through Radical Polymerization of OEO19MA.

Radical polymerization of poly(ethylene glycol) methyl ether methacrylate (OEO19MA, Mn ∼ 950) at an initial monomer concentration of 150 mM was investigated as a function of solvent composition. Conventional and controlled radical polymerizations in anisole at 60 °C converged at approximately the same equilibrium monomer concentration ([M]eq) of ∼38 mM, suggesting that livingness or diminished termination did not affect the thermodynamic parameters of polymerization. Conventional radical polymerizations (RPs) in anisole, dimethylformamide (DMF), toluene, and 1×PBS buffered water were taken to approximately 98% thermal initiator decomposition to determine [M]eq at reaction completion within a broad temperature range. The enthalpy (ΔHp) and entropy (ΔSp°) of polymerization were solvent-dependent. Polymerizations in 1×PBS were the most thermodynamically favorable, followed by those in DMF, toluene, and anisole. -ΔHp and -ΔSp increased with the square of the difference in the Hansen solubility parameters of poly(ethylene glycol) and the solvent. It is proposed that poor solvents favor polymer-polymer interactions over polymer-solvent interactions, which improves the thermodynamic polymerizability.

Molecular Aggregation Structure and Surface Properties of Biomimetic Catechol-Bearing Poly[2-(perfluorooctyl)ethyl acrylate] and Its Application to Superamphiphobic Coatings.

The molecular aggregation structure and surface properties of a catechol-bearing fluoropolymer, P(FAC8-co-DOPAm), which was synthesized by conventional radical copolymerization of 2-(perfluorooctyl)ethyl acrylate (FAC8) and N-(3,4-dihydroxyphenethyl)acrylamide (DOPAm), and its application to the superamphiphobic surfaces are presented. The crystallinity of P(FAC8-co-DOPAm) was lower than that of poly[2-(perfluorooctyl)ethyl acrylate] (PFAC8). The perfluoroalkyl (Rf) groups were ordered on the surface with CF3 terminals exposed to air, and the Rf ordering was influenced by thermal history: the thermally annealed film exhibited higher Rf ordering than the unannealed one. The surface free energy was estimated to be γ = 7.32 mJ m–2 for both the unannealed and annealed films. Based on contact angle measurement, various interfacial structures of water and oils in accordance with the surface aggregation structure of Rf groups were proposed. Dewetting of the PFAC8 film at elevated temperature was suppressed by the introduction of catechol groups in the backbone. The degradation temperature of PFAC8 was improved significantly, and the evaporation of the low molar mass-polymer was inhibited by the introduction of catechol groups under both nitrogen and air atmospheres. The hydrophobicity of the copolymer films could be healed after the surface was damaged by vacuum ultraviolet (VUV) irradiation. This copolymer was used to create superamphiphobic fabrics and halloysite nanotube (HNT)-based organic/inorganic hybrid coatings successfully. Wetting behaviors of the superamphiphobic fabrics and coatings both follow the Cassie–Baxter wetting model.

MP67-19 DUCTAL ADENOCARCINOMA OF THE PROSTATE: A SYSTEMATIC REVIEW AND META-ANALYSIS OF INCIDENCE, PRESENTATION AND MANAGEMENT

MP67-19 DUCTAL ADENOCARCINOMA OF THE PROSTATE: A SYSTEMATIC REVIEW AND META-ANALYSIS OF INCIDENCE, PRESENTATION AND MANAGEMENT

The Promising Future of Fluoropolymers

AbstractThis article aims at showing the usefulness of fluoropolymers (FPs), supplying an overview of their synthesis, applications, and recycling. FPs are currently prepared by conventional radical polymerization of fluoromonomers. These specialty polymers, produced in low tonnage compared to that of commodity ones, display outstanding properties, such as chemical, oxidative, and thermal resistances, low refractive index, dissipation factor, permittivity, and water absorptivity, and excellent weatherability and durability. More recent routes for their preparations are suggested, controlled or not, leading to random, alternated, block, graft, dendrimers, or multiarm copolymers, as well as their applications ranging from coatings to high performance (thermoplastic) elastomers, energy related‐materials (e.g., fuel cell membranes, components for lithium‐ion batteries, electroactive devices, and photovoltaics) to original and surfactants, optical devices, organic electronics, composites, and shape memory polymers.

Strong Cationic Radical Initiator‐Based Design of a Thermoresponsive Hydrogel Showing Drastic Volume Transition

AbstractIn this study, a millimeter‐sized thermoresponsive poly(N‐isopropylacrylamide) (PNIPAAm) gel is prepared by free radical polymerization using 2,2′‐azobis‐[2‐(1,3‐dimethyl‐4,5‐dihydro‐1H‐imidazol‐3‐ium‐2‐yl)]propane triflate (ADIP), a radical initiator possessing a strong cationic group that is newly developed. By comparing this gel with a PNIPAAm gel prepared using a conventional radical initiator, 2,2′‐azobisisobutyronitrile, the following properties are found: 1) the cationic residue of ADIP is introduced in the gel, and 2) the PNIPAAm gel prepared using ADIP exhibits a discontinuous volume transition as a function of temperature and rapid shrinking in response to temperature jump. This thermoresponsive behavior is attributed to the low polymer fraction in the gel prepared using ADIP. The ADIP‐based design of the thermoresponsive hydrogel investigated herein may contribute to the design of functional soft materials.

Synthesis, Structure, and Crystallization Behavior of Amphiphilic Heteroarm Molecular Brushes with Crystallizable Poly(ethylene oxide) and n-Alkyl Side Chains

A series of heteroarm amphiphilic molecular brushes (AMBs) with poly(ethylene glycol) (PEG) and long chain n-alkyl side chains were synthesized via conventional free radical polymerization (FRP) of...

Photoredox Catalysis of Aromatic β-Ketoesters for in Situ Production of Transient and Persistent Radicals for Organic Transformation.

Radical formation is the initial step for conventional radical chemistry. Reported herein is a unified strategy to generate radicals in situ from aromatic β-ketoesters by using a photocatalyst. Under visible-light irradiation, a small amount of photocatalyst fac-Ir(ppy)3 generates a transient α-carbonyl radical and persistent ketyl radical in situ. In contrast to the well-established approaches, neither stoichiometric external oxidant nor reductant is required for this reaction. The synthetic utility is demonstrated by pinacol coupling of ketyl radicals and benzannulation of α-carbonyl radicals with alkynes to give a series of highly substituted 1-naphthols in good to excellent yields. The readily available photocatalyst, mild reaction conditions, broad substrate scope, and high functional-group tolerance make this reaction a useful synthetic tool.

Photoredox Catalysis of Aromatic β‐Ketoesters for in Situ Production of Transient and Persistent Radicals for Organic Transformation

AbstractRadical formation is the initial step for conventional radical chemistry. Reported herein is a unified strategy to generate radicals in situ from aromatic β‐ketoesters by using a photocatalyst. Under visible‐light irradiation, a small amount of photocatalyst fac‐Ir(ppy)3 generates a transient α‐carbonyl radical and persistent ketyl radical in situ. In contrast to the well‐established approaches, neither stoichiometric external oxidant nor reductant is required for this reaction. The synthetic utility is demonstrated by pinacol coupling of ketyl radicals and benzannulation of α‐carbonyl radicals with alkynes to give a series of highly substituted 1‐naphthols in good to excellent yields. The readily available photocatalyst, mild reaction conditions, broad substrate scope, and high functional‐group tolerance make this reaction a useful synthetic tool.

One‐step synthesis of macromonomers catalyzed by phosphazene base

AbstractHerein, we report one‐step synthesis of polymethacrylates‐based macromonomers (MMs) in the presence of an organocatalyst phosphazene base (t‐BuP4) and a functional initiator N‐butyl‐4‐vinylbenzamide (N‐BVBA) containing a secondary amide and a styrenic double bond. A series of styrenic MMs with controlled molecular weight and relatively narrow polydispersity were synthesized under mild conditions. Detailed NMR analyses of the initiation process suggested that the anionic polymerization was initiated by nitrogen anion generated from abstraction of the proton from the secondary amide. NMR and MALDI‐TOF MS analyses confirmed: (1) the selective polymerization of methacrylate‐type double bonds, (2) controlled chain‐end functionality of MMs with an unreacted styrenic double bond, as well as (3) the absence of transesterification between N‐BVBA and methacrylate monomers. Furthermore, the homopolymerization and copolymerization of the MMs with comonomers were carried out for the preparation of graft copolymers. Through conventional radical polymerization, graft copolymers with different grafting densities were obtained at high MMs conversions, indicating the high reactivity of MMs. Thus, the one‐step approach demonstrates a simple metal‐free access to the controlled synthesis of MMs, and the prepared MMs can polymerize efficiently to convert into graft copolymers.

Poly(acrylic acid)/palygorskite microgel via radical polymerization in aqueous phase for reinforcing poly(vinyl alcohol) hydrogel

Poly(acrylic acid)/palygorskite microgel (PAA/Pal) with three-dimensional network structure was synthesized in the aqueous phase by conventional free radical polymerization. The functionalized Pal (f-Pal) acted as the multiple cross-linker in the polymerization system. The composition, structure, and morphology of the microgels were characterized by FT-IR, XRD, TGA and SEM. The microgel was introduced into the poly(vinyl alcohol) solution (PVA) to prepare the PAA/Pal microgel reinforced PVA hydrogel. During the evaporation-swelling (E-S) process, the OH and COOH in microgel form a new cross-linked network through the synergistic hydrogen bonding with the OH in PVA. The tensile strength of hydrogels increased from 1.46 MPa to 2.71 MPa, and the elastic modulus increased from 233 kPa to 756 kPa with the addition of microgels. The hydrogel in the study had excellent mechanical strength and recovery properties, and was expected to be used in tissue engineering and soft machines.

Synthesis, characterization and thermokinetic analysis of the novel sugar based styrene co-polymer

Abstract A new α-chloralose (1,2-O-(R)-trichloroethylidene-α-D-glucofuranose)-based copolymer of styrene (PSVTEG) (2) was synthesized from vinyl (hydroxyl) furan monomer (1) and styrene by a conventional free radical polymerization reaction. The thermal decomposition kinetics of polymer were investigated by means of thermogravimetric analysis in dynamic nitrogen atmosphere at different heating rates. The apparent activation energy for the main stage thermal decomposition of the copolymer PSVTEG (2) was calculated using the Flynn-Wall-Ozawa and found to be 159.0±3 kj/mol. In addition, the activation energy value was calculated according to Coats-Redfern method and found to be compatible with the obtained result. The thermogram of the glycopolymer (PSVTEG) (2) has two decomposition stages and the calculated activation energy indicated that the main degradation stage is a nonspontaneous process (integral form 1/(1−α)2 for F3).