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As a follow-up of the paper “Engineering of silica-supported platinum catalysts with hierarchical porosity combining latex synthesis, sonochemistry and sol-gel process – I. Material preparation” (A.F. Sierra-Salazar, et at., Microporous Mesoporous Mater. 234 (2016) 207–214. http://dx.doi.org/10.1016/j.micromeso.2016.07.009 ), we propose waterborne Pt-based catalysts with hierarchical porosity and controlled Pt nanoparticles (NPs) distribution within the support. The materials exhibit specific surface areas and total pore volumes as high as 490 m 2 g −1 and 0.77 cm 3 g −1 , with ∼5 nm Pt NPs mainly located in the macropores. The Pt NPs were characterised using X-ray photoemission spectroscopy (XPS) and high resolution transmission electron microscopy (HR-TEM). Considering the selectivity challenge of the catalytic hydrogenation of halonitrobenzenes to produce haloanilines, which are important raw materials for several industrial products, we evaluated these hierarchically porous catalysts for the hydrogenation of p -chloronitrobenzene ( p -CNB) in batch mode to produce p -chloroaniline ( p -CAN). It was possible to obtain up to 100% selectivity at 80% conversion and initial reaction rates up to 34 mol CNB min −1 mol Pt −1 . Such selectivity was higher than that exhibited by a commercial Pt/SiO 2 catalyst (up to 92%). [ABSTRACT FROM AUTHOR]

The use of iodocompounds in radical polymerization presents a straightforward way to prepare controlled macromolecular architectures. Herein, ab initio emulsion polymerization of styrene has been successfully performed by iodine transfer polymerization using methyl-2-iodopropionate as transfer agent, 2,2'-azobis[ N -(2-carboxyethyl)-2-methylpropionamidine]tetrahydrate (VA-057) as initiator and dodecyl sulfate sodium salt (SDS) as surfactant, yielding stable and uncoloured latexes (e.g. styrene conversion = 76%, M n,theoretical = 7800 g mol −1 , M n,SEC = 8400 g mol −1 , M w /M n = 1.84, particle diameter d p = 55 nm with a monomodal particle size distribution). Hence, the molecular weight of the polymer chains could be accurately controlled by the concentration of transfer agent. Furthermore, a poly(styrene)- b -poly(styrene- co -butyl acrylate) block copolymer latex was synthesized in seeded emulsion polymerization, proving the living character of the polymerization. [ABSTRACT FROM AUTHOR]

Abstract: Iodo-terminated polystyrene and poly(methyl acrylate) (PMA-I) were synthesized by reverse iodine transfer polymerization. The resulting polymers were coupled by atom transfer radical coupling using Cu(I)/linear amino-ligand catalysts in the presence of reducing Cu(0). The efficiency of the coupling reaction is discussed as a function of various factors, namely, the Cu(0) particle sizes, the number of nitrogen present in the ligand structure, the type of halogen associated with Cu(I) (CuX, X=I, Br, Cl), the nature of the polymer and the nature of the chain ends. In particular, a quantitative coupling (100%) was obtained with a CuBr/HMTETA system in the presence of nanosized Cu(0) for PMA-I, thus opening for the first time a facile route to telechelic and multiblock poly(acrylate)-based structures. [Copyright &y& Elsevier]

Abstract: Taking benefit of previously obtained results, stable complex organic–inorganic hybrid suspensions are successfully prepared by mixing a polystyrene latex aqueous suspension, a titania hydrosol and a nonionic triblock copolymer. These suspensions can be then deposited as thin films on dense or porous substrates. Solvent evaporation induces the formation of spherical micelles by self-assembly of the amphiphilic molecules during the drying of the films. Two types of isolated spherical macropores (few ten nanometers) and mesopores (4–5 nm) are generated inside the layers by the thermal removal of the polystyrene particles and of the micelles, respectively. The remaining inorganic network exhibits an additional interconnected microporosity with a mean pore size of 1.5 nm, resulting from the aggregation of the anatase nanoparticles. A complete removal of the templating units at low temperature is possible using the photocatalytic properties of the anatase network. Such layers exhibit attractive properties for the design of ceramic membranes. They can be advantageously used in order to increase the permeability of the separative layer and to reduce the number of intermediate layers of these asymmetric structures. [Copyright &y& Elsevier]

Abstract: Nitroxide-mediated radical polymerization was used to synthesize poly(1,1,2,2-tetrahydroperfluorodecyl acrylate) homopolymer, PFDA, and to tailor the synthesis of semifluorinated polystyrene-b-PFDA block copolymer, PS-b-PFDA. The solubility of the polymers was investigated in the solvent carbon dioxide (CO2) using cloud point and light scattering techniques. The solvent quality of CO2 for PFDA homopolymer was shown to increase with CO2 pressure and this information coupled with the size of the block copolymer species indicated the formation of PS-b-PFDA micelles. Residual PS homopolymer remained soluble in PS-b-PFDA micelles at low pressure and induced the formation of a second population of larger aggregates when the solvent quality was tuned. [Copyright &y& Elsevier]

Abstract: Dispersion polymerization of 2-hydroxyethyl methacrylate (HEMA) has been successfully performed in supercritical carbon dioxide at P=370bar and T=65°C with azobis(isobutyronitrile) as initiator and a hydrophilic/CO2-philic poly(ethylene oxide)-b-poly(1,1,2,2-tetrahydroperfluorodecyl acrylate) (PEO-b-PFDA) block copolymer as steric stabilizer. The PEO-b-PFDA (2K/21K) block copolymer was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Spherical particles of poly(HEMA) were obtained in the range of 200–400nm diameter size with a narrow particle size distribution (Dw/Dn<1.1). The effect of the stabilizer concentration on the dispersion polymerization was investigated from 20w/w% down to 3.5w/w% versus HEMA. Precipitation polymerization in the absence of stabilizer lead to the formation of large aggregates of partially coalesced particles whereas discrete spherical particles of poly(HEMA) were obtained by dispersion polymerization even at low concentration of PEO-b-PFDA (3.5w/w% versus HEMA). [Copyright &y& Elsevier]

An innovative route based on a novel photo-latent ROMP initiator has been explored to synthesize polynorbornene latex particles in miniemulsion. Operation conditions were strongly improved by the use of an annular LED photo-reactor, increasing the uniformity of radiation distribution and enabling to control atmosphere and stirring throughout irradiation. Several parameters (droplet size, irradiance, pre-catalyst structure) were studied in order to improve the monomer conversion profiles, which eventually led to the production of latex with high norbornene conversion (>90%) and 10% solids content. Particular attention was paid to the polymer microstructure, which was found to be highly dependent on the type of initiation mechanism. Image 1 • Synthesis of polynorbornene particles by ROMP in miniemulsion. • Using of efficient photolatent ROMP initiator. • Using of an annular glass photoreactor, allowing both miniemulsion and ROMP under well-controlled inert atmosphere. • High Nb conversions have been reached very quickly (> 90%). • Control of the cis/trans ratio of the polynorbornene thanks to the choice of Ruthenium precatalyst. [ABSTRACT FROM AUTHOR]

In order to contribute to the shift from petro-based chemistry to biobased chemistry, necessary to minimize the environmental impacts of the chemical industry, 2-methoxy-4-vinylphenol (4-vinyl guaiacol, 4VG) was used to synthesize a platform of biobased monomers. Thus, nine biobased monomers were successfully prepared. The synthesis procedures were investigated through the green metrics calculations in order to quantify the sustainability of our approaches. Their radical homopolymerization in toluene solution initiated by 2,2′-azobis(2-methylpropionitrile) (AIBN) was studied and the effect of residual 4VG as a radical inhibitor on the kinetics of polymerization was also explored. The new homopolymers were characterized by proton nuclear magnetic resonance (1H-NMR) spectroscopy, size exclusion chromatography and thermal analyses (dynamical scanning calorimetry DSC, thermal gravimetric analysis TGA). By varying the length of the alkyl ester or ether group of the 4VG derivatives, homopolymers with Tg ranging from 117 °C down to 5 °C were obtained. These new biobased monomers could be implemented in radical copolymerization as substitutes to petro-based monomers to decrease the carbon footprint of the resulting copolymers for various applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green recycling process of cathode materials from LIBs using supercritical CO 2. • scCO 2 as a green solvent for critical metal extraction at 60 °C and 250 bar. • Poly(VBPDA- co -FDA) copolymer as leaching agent, macro-ligand, and extracting agent. • H 2 O 2 and ethanol as reducing agent for Co2+ complexation in scCO 2 from LiCo(III)O 2. • Recovery yield up to 75 % of Co and Li from LiCoO 2. Supercritical CO 2 (scCO 2) extraction assisted by complexing copolymers is a promising process to recover valuable metals from lithium-ion batteries (LIBs). CO 2 , in addition to being non-toxic, abundant and non-flammable, allows an easy separation of metal-complexes from the extraction medium by depressurization, limiting the wastewater production. In this study, CO 2 -philic gradient copolymers bearing phosphonic diacid complexing groups (poly(vinylbenzylphosphonic diacid- co -1,1,2,2-tetrahydroperfluorodecylacrylate), p(VBPDA- co -FDA)) were synthesized for the extraction of lithium and cobalt from LiCoO 2 cathode material. Notably, the copolymer was able to play the triple role of leaching agent, complexing agent and surfactant. The proof of concept for leaching, complexation and extraction was achieved, using two different extraction systems. A first extraction system used aqueous hydrogen peroxide as reducing agent while it was replaced by ethanol in the second extraction system. The scCO 2 extraction conditions such as extraction time, temperature, functional copolymer concentration, and the presence of additives were optimized to improve the metals extraction from LiCoO 2 cathode material, leading to an extraction efficiency of Li and Co up to ca. 75 % at 60 °C and 250 bar. [ABSTRACT FROM AUTHOR]

[Display omitted] Polymers containing morpholine or thiomorpholine (oxide) functions showed an increased interest for biological applications in the recent years. Morpholine containing polymers provide high hydrophilicity and comparable biocompatibility with polyethylene glycol (PEG) which is the gold standard in biology. In particular, poly(N -acryloyl) morpholine is one of the most cited polymers containing morpholine, with applications in drug delivery, protein detection or the design of anticoagulant materials. However, there are very few examples of polymers derived from thiomorpholine and thiomorpholine oxide. Compared to morpholine polymers, thiomorpholine containing polymers are less hydrophilic, while thiomorpholine oxide derived polymers are more hydrophilic. Thiomorpholine and thiomorpholine oxide polymers are biocompatible and were recently studied as oxidation sensitive materials and as hemocompatible materials. This review highlights the correlation between the structural characteristics of morpholine and thiomorpholine (oxide) based polymers and their use in various biological applications. [ABSTRACT FROM AUTHOR]

Precious metals such as palladium (Pd) have many applications, ranging from automotive catalysts to fine chemistry. Platinum group metals are, thus, in massive demand for industrial applications, even though they are relatively rare and belong to the list of critical materials for many countries. The result is an explosion of their price. The recovery of Pd from spent catalysts and, more generally, the development of a circular economy process around Pd, becomes essential for both economic and environmental reasons. To this aim, we propose a sustainable process based on the use of supercritical CO2 (i.e., a green solvent) operated in mild conditions of pressure and temperature (p = 25 MPa, T = 313 K). Note that the range of CO2 pressures commonly used for extraction is going from 15 to 100 MPa, while temperatures typically vary from 308 to 423 K. A pressure of 25 MPa and a temperature of 313 K can, therefore, be viewed as mild conditions. CO2-soluble copolymers bearing complexing groups, such as pyridine, triphenylphosphine, or acetylacetate, were added to the supercritical fluid to extract the Pd from the catalyst. Two supported catalysts were tested: a pristine aluminosilicate-supported catalyst (Cat D) and a spent alumina supported-catalyst (Cat A). An extraction conversion of up to more than 70% was achieved in the presence of the pyridine-containing copolymer. The recovery of the Pd from the polymer was possible after extraction, and the technological and economical assessment of the process was considered. [ABSTRACT FROM AUTHOR]

The worldwide continual reinforcement of regulations for the production of cleaner fuels along with the larger demand for energy urge us to develop hydrotreatment sulfide catalysts exhibiting higher activity in hydrodesulfurization reactions and explore innovative synthesis strategies. In this work, a novel one‐pot synthesis method of unsupported NiMoS catalysts in water at ambient pressure and moderate temperature is described. The reaction conditions including pH variations and addition of a copolymer structuring agent were thoroughly investigated. Catalytic performances of the prepared bulk NiMoS catalysts were measured for the hydrodesulfurization of two model sulfur molecules, representative of FCC gasoline. Catalysts prepared at pH 7 without or with polymer exhibited roughly similar activity, resulting however from different characteristics favorable for catalyst efficiency probably compensating one another, i. e. a very high promotion rate for the first one and smaller particles along with larger specific surface area for the second. [ABSTRACT FROM AUTHOR]

Several CoMoS/carbons were successfully synthetized using hydrothermal-type approaches and a subsequent surface reaction for the promotion step with Co. The effect of the microstructure of carbons used as a matrix for CoMoS-based catalysts was studied in the case of hydrotreating reactions. It was found that 1D (nanofibers/tubes) or 2D (nanosheets) carbon nanostructures may influence the characteristics of the CoMoS crystallites (dispersion, promotion rate and orientation of the slabs) and as a consequence the catalytic properties. In particular, the HDS mechanism of the substituted 4-MethylDiBenzoThiophene (4-MDBT) was found to be microstructure-dependent, as well as the selectivity of 3-MethylThiophene (3-MT) HDS/2,3-DiMethylBut-2-eNe (2,3-DM2BN) hydrogenation. [ABSTRACT FROM AUTHOR]

Functionalized mesoporous silica particles offer excellent chemical and morphological properties, making them ideal adsorbents or drug carriers. However, their synthesis involves several energy- and resource-intensive steps, resulting in high economic and environmental costs. In this study, we report a strategy for the direct design of mesoporous silica with ordered mesopores densely functionalized by polyacid chains. The aqueous process relies on polyion complex micelles acting as pH-responsive multifunctional agents. They are first associated to direct the mesostructure of silica, and are then dissociated by a change in pH to reveal the material's mesoporosity and yield functional pores. Ordered mesoporous particles with controlled structure and particle size were obtained, showing dense functionalization of up to 2.1 mmol.g SiO2 −1 of carboxylic acid functions, which were fully accessible to ionic exchange in aqueous solution. These highly functionalized materials were then evaluated as reversible adsorbents for the removal of a cationic dye (auramine O). The results revealed high dye uptakes, from 130 to 237 mg.g SiO2 −1, which were up to 193 % higher than those achieved with non-functional calcined mesoporous silica particles. These uptakes correlated with the mesoporous volume of the materials, with an average density of around one auramine molecule per nm3 of pore. In addition, the materials exhibited excellent dye adsorption/desorption cyclability by pH stimuli in aqueous solutions under mild conditions, with an average desorption efficiency of 96 % in just 30 min. These results therefore represent an attractive strategy for the design of efficient and sustainable adsorbents for water purification. [Display omitted] • Eco design of ordered mesoporous silica functionalized with poly(acrylic acid) chains. • Direct formation of functionalized mesopores in one pot and two steps. • Highly accessible acid functions are located in hexagonal and cubic mesostructures. • Particle size is controlled by steric stabilization of the surface. • High cationic dye uptake in water, excellent cyclability in response to pH stimuli. [ABSTRACT FROM AUTHOR]

Thermo-responsive hydrophilic polymers, including those showing tuneable lower critical solution temperature (LCST), represent a continuous subject of exploration for a variety of applications, but particularly in nanomedicine. Since biological pH changes can inform the organism about the presence of disequilibrium or diseases, the development of dual LCST/pH-responsive hydrophilic polymers with biological potential is an attractive subject in polymer science. Here, we present a novel polymer featuring LCST/pH double responsiveness. The monomer ethylthiomorpholine oxide methacrylate (THOXMA) can be polymerised via the RAFT process to obtain well-defined polymers. Copolymers with hydroxyethyl methacrylate (HEMA) were prepared, which allowed the tuning of the LCST behaviour of the polymers. Both, the LCST behaviour and pH responsiveness of hydrophilic PTHOXMA were tested by following the evolution of particle size by dynamic light scattering (DLS). In weak and strong alkaline conditions, cloud points ranged between 40–60 °C, while in acidic medium no LCST was found due to the protonation of the amine of the THOX moieties. Additional cytotoxicity assays confirmed a high biocompatibility of PTHOXMA and haemolysis and aggregation assays proved that the thiomorpholine oxide-derived polymers did not cause aggregation or lysis of red blood cells. These preliminary results bode well for the use of PTHOXMA as smart material in biological applications. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of a platform of novel functional fluorinated gradient copolymers soluble in liquid and supercritical CO2 is reported. These functional copolymers are bearing different types of complexing units (pyridine, triphenylphosphine, acetylacetate, thioacetate, and thiol) which are well-known ligands for various metals. They have been prepared by reversible addition–fragmentation chain-transfer (RAFT) polymerization in order to obtain well-defined gradient copolymers. The copolymers have been characterized by proton nuclear magnetic resonance (1H-NMR) spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, thermal gravimetric analysis (TGA), dynamical scanning calorimetry (DSC) and cloud point measurements in dense CO2. All the investigated metal-complexing copolymers are soluble in dense CO2 under mild conditions (pressure lower than 30 MPa up to 65 °C), confirming their potential applications in processes such as metal-catalyzed reactions in dense CO2, metal impregnation, (e.g., preparation of supported catalysts) or metal extraction from various substrates (solid or liquid effluents). Particularly, it opens the door to greener and less energy-demanding processes for the recovery of metals from spent catalysts compared to more conventional pyro- and hydro-metallurgical methods. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNC) possess desirable mechanical and optical properties that make them a candidate in the development of the next generation of polymer‐based composites. However, CNC also have a critical issue associated with their use: their hydrophilicity and incompatibility with hydrophobic polymers. CNC surface properties must be modified for them to be successfully implemented by the industrial sector. Grafting (co)polymers chains on the CNC surface can provide compatibility to CNC with hydrophobic matrices and expand their potential range of applications. In this communication preliminary results of a simple method to functionalize CNC surface are reported using block copolymers, where a cationic block anchors via complexation to the anionically charged CNC surface and the other block acts as a stabilizing block, providing dispersibility in various solvents. This is a much simpler and less expensive method than current routes based on covalent modification. The block copolymers poly(polyethylene glycol methacrylate)‐b‐poly(N‐butyl‐N′‐vinyl imidazolium bromide) (PPEGMA‐b‐PBuVIm) and poly(styrene)‐b‐PBuVIm (PS‐b‐PBuVIm) are first synthesized via nitroxide‐mediated polymerization and then non‐covalently adsorbed on the CNC surface. The functionalization has been confirmed via FT‐IR and TGA. The dispersion of polymer‐modified CNC materials in organic solvents is evaluated via dynamic light scattering. Modified CNC yielded stable dispersions in organic solvents. [ABSTRACT FROM AUTHOR]

ABSTRACT Reverse iodine transfer polymerization (RITP), offering the appealing potential of the in situ generation of transfer agents out of molecular iodine I2, is employed in the synthesis of anionic amphiphilic diblock copolymers of poly(styrene) and poly(acrylic acid). Starting with well-characterized poly(styrene) as macro-transfer agents synthesized by RITP, diblock copolymers poly(styrene)- b-poly( tert-butyl acrylate) of various lengths are successfully yielded in solution with a good architectural control. These blocks are then subjected to acid deprotection and subsequent pH control to give rise to anionic amphiphilic poly(styrene)- b-poly(acrylic acid). Besides, homopolymers of tert-butyl acrylate are produced by RITP both in solution and in emulsion. Furthermore, a fruitful trial of the synthesis of diblock copolymers poly( tert-butyl acrylate)- b-poly(styrene) is carried out through chain extension of the poly( tert-butyl acrylate) latex as a macro-transfer agent in seeded emulsion polymerization of styrene. Finally, the prepared block copolymer is deprotected to bring about its amphiphilic nature and a pH control caters for its anionic character. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4389-4398 [ABSTRACT FROM AUTHOR]

Highlights: [•] Two types of amphiphatic sulfonated macro-RAFT agents were synthesized. [•] A combination of acrylic acid and AMPS units gave the best results regarding stability and morphology. [•] A complexing activity of the RAFT oligomers towards the metal oxide surface is needed. [•] “Single-headed” snowman particles were obtained for the first time in this system. [ABSTRACT FROM AUTHOR]

Abstract: Solution polymerization of 1,1,2,2-tetrahydroperfluorodecyl acrylate initiated by 2,2′-azobis(isobutyronitrile) (AIBN) at 65°C in the presence of molecular iodine I2 has been studied. The process, called reverse iodine transfer polymerization (RITP), efficiently controls the molecular weight (determined by 1H NMR) and the structure of the polymer. For instance, a poly(1,1,2,2-tetrahydroperfluorodecyl acrylate) sample of Mn ,NMR =5200gmol−1 (Mn ,theoretical =5000gmol−1), with a monomer conversion of 97% was successfully prepared. The iodine end-capped structure of the polymers (A–M n –I, where n is the mean number degree of polymerization) was further demonstrated by mass-assisted laser desorption ionization time-of-flight (MALDI-TOF). When targeting very low degrees of polymerization (e.g. DP n =5), monomer conversion reached its maximum before the end of the induction period (incomplete consumption of iodine and of the A–I adduct) leading to higher than expected molecular weights. This could be a limitation for RITP when targeting very low molecular weight oligomers (DP n <10). Finally, an efficient functionalization method was used to end-cap the PFDA polymer chains with a hydroxyl or a carboxylic acid function. The iodine atom at the chain end was displaced by 2-mercaptoethanol or 2-mercaptoacetic acid in basic media to yield the corresponding alcohol or acid. [Copyright &y& Elsevier]

Hybrid latexes based on cerium oxide nanoparticles are synthesized via an emulsifier-free process of emulsion polymerization employing amphiphatic macro-RAFT agents. Poly(butyl acrylate- co-acrylic acid) random oligomers of various compositions and chain lengths are first obtained by RAFT copolymerization in the presence of a trithiocarbonate as controlling agent. In a second step, the seeded emulsion copolymerization of styrene and methyl acrylate is carried out in the presence of nanoceria with macro-RAFT agents adsorbed at their surface, resulting in a high incorporation efficiency of cerium oxide nanoparticles in the final hybrid latexes, as evidenced by cryo-transmission electron microscopy. [ABSTRACT FROM AUTHOR]

Abstract: A new method called reverse iodine transfer polymerization (RITP), based on the in situ generation of transfer agents using molecular iodine I2, was applied to the synthesis of poly(vinylbenzyl chloride). Well-defined diblock copolymers poly(vinylbenzyl chloride)-b-polystyrene with different chain lengths were then successfully produced through sequential polymerization of styrene. The polydispersity index values Mw /Mn ranged from 1.4 to 1.6 for all the homopolymers and diblock copolymers. The diblock copolymers could be synthesized with equally good results by starting with either poly(vinylbenzyl chloride) or polystyrene as macrotransfer agents. The diblock copolymers were then quaternized with triethylamine to prepare cationic amphiphilic diblock copolymers. [Copyright &y& Elsevier]

Abstract: Iodine transfer polymerization of vinyl acetate in bulk, initiated by α,α′-azobisisobutyronitrile at 80°C, has been successfully performed in the presence of an α,ω-diiodo-poly(dimethylsiloxane) macrotransfer agent. The formation of a triblock copolymer PVAc-b-PDMS-b-PVAc has been proved by 1H NMR and size exclusion chromatography analyses. The analysis of the chain-ends has been performed using 1H NMR. It was found that a large amount of inverse chain-ends is present at the end of the polymerization. Moreover, the formation of several other side products by degradation of the functional chain-ends has been evidenced. [Copyright &y& Elsevier]

Anionic ring-opening polymerization (AROP) of 2-ethyl-2-oxo-1,3,2-dioxaphospholane (EP) has been utilized to create alternative hydrophilic moieties for utilization in surfactants. The current "go-to" hydrophilic unit is poly(ethylene glycol) (PEG), but this is non-biodegradable and there is some evidence that its use can lead to accumulation of toxic by-products. We have created new approaches leading to water-dispersible, fully degradable amphiphilic block copolymers. Our approach utilized poly(ε-caprolactone)-based macroinitiators in a solvent free process with organocatalyst DBU. We have prepared a comprehensive set of novel amphiphilic PCL-b-PEP block copolymers including linear diblock, triblock and star diblock copolymers characterized by SEC, 1H and 31P NMR and MALDI-TOF analyses. Supercritical carbon dioxide (scCO2) was exploited to efficiently extract the residual EP monomer leading to significantly increased gravimetric yields of purified product compared to conventional techniques such as dialysis. The self-assembly of the amphiphilic copolymers in water was investigated by DLS and cryo-TEM and their surface-activity as a function of concentration was investigated by tensiometry showing behavior that matches or exceeds commercially available surfactants. [ABSTRACT FROM AUTHOR]

We report a very simple synthesis strategy for the formation of moderately porous ionosilica materials containing ammonium groups. We synthesized an ionosilica xerogel and an ionosilica aerogel, either via conventional or supercritical work‐up. The synthesis scheme of both precursor and ionosilica materials could easily be up‐scaled to a 100 g scale. All syntheses and work‐up procedures are sustainable as no additional agent and very low quantities of solvents were used, and no additional purifications steps were necessary. Although both materials show excellent anion exchange properties for chromate adsorption, noticeable differences were found regarding the thermodynamics of the exchange process. We attribute these differences to different surface chemistries of the materials, induced by the different work‐up procedures. Due to the easy availability of high quantities of material, ionosilicas can be implemented as functional ion exchange materials in larger scale processes, thus opening new fields of applications. [ABSTRACT FROM AUTHOR]

In the search of smarter routes to control the conditions of N‐heterocyclic carbene (NHCs) formation, a two‐component air‐stable NHC photogenerating system is reported. It relies on the irradiation at 365 nm of a mixture of 2‐isopropylthioxanthone (ITX) with 1,3‐bis(mesityl)imidazoli(ni)um tetraphenylborate. The photoinduced liberation of NHC is evidenced by reaction with a mesitoyl radical to form an NHC‐radical adduct detectable by electron spin resonance spectroscopy. The NHC yield can be determined by 1H NMR spectroscopy through the formation of a soluble and stable NHC–carbodiimide adduct. To deprotonate the azolium salt and liberate the NHC, a mechanism is proposed in which the role of base is played by ITX radical anion formed in situ by a primary photoinduced electron‐transfer reaction between electronically excited ITX (oxidant) and BPh4− (reductant). An NHC yield as high as 70 % is achieved upon starting with a stoichiometric ratio of ITX and azolium salt. Three different photoNHC‐mediated polymerizations are described: synthesis of polyurethane and polyester by organocatalyzed step‐growth polymerization and ring‐opening copolymerization, respectively, and generation of polynorbornene by ring‐opening metathesis polymerization using an NHC‐coordinated Ru catalyst formed in situ. [ABSTRACT FROM AUTHOR]

This review highlights the design and synthesis of biobased monomers from renewable resources for the preparation of latexes in aqueous dispersed media. Biobased polymers have been widely studied and are still a hot topic as environmental concerns and regulations require the use of green chemistry principles as guidelines for the synthesis of new polymer materials. Consideration should equally be given to green polymerization processes such as industrially relevant aqueous emulsion and suspension polymerizations. However, the synthesis and polymerization of biobased monomers through polymerization in aqueous dispersed media have not been sufficiently explored. Hence, constraints and opportunities arising from previous research work in this area will be presented focusing on aqueous (mini)emulsion and suspension polymerizations. [ABSTRACT FROM AUTHOR]

Hierarchically porous materials offer the opportunity for catalyst development in regards to improving catalytic performances. In the present work, the combination of latex synthesis, sonochemical reduction and two-step catalysed sol-gel process has been demonstrated to be a versatile method for preparing supported catalysts with tailored hierarchical porosity. This method has been used to prepare porous Pt/SiO2 catalysts with mesopore and macropore size ranges as large as 2-15 nm and 90-400 nm, respectively. These hierarchically porous catalysts presented an excellent catalytic performance for the selective hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN). Selectivity values up to 100% at 80% conversion of p-CNB and initial reaction rates up to 74.0 molCNB/min molPt were obtained, while a commercial catalyst exhibited both a lower selectivity of 90.8% and a lower initial reaction rate of 47.7 molCNB/min molPt. [ABSTRACT FROM AUTHOR]

The use of functional CO 2 -philic polymers in supercritical carbon dioxide (scCO 2 ) for a greener method of extracting Pd from spent catalysts has been investigated. Three fluorinated polymers bearing complexing units (a thiol-terminated poly(1,1,2,2-tetrahydroperfluorodecyl acrylate) homopolymer PFDA-SH, a poly(1,1,2,2-tetrahydroperfluorodecyl acrylate- co -diphenylphosphinostyrene) gradient copolymer P(FDA- co -DPPS), and a thiol-terminated gradient copolymer P(FDA- co -DPPS)-SH) were synthesized and successfully used to extract palladium from commercial Pd/Al 2 O 3 supported catalysts (beads and pellets with 0.5 wt.% and 5 wt.% Pd loading, respectively). These non-destructive extractions were carried out in scCO 2 under mild conditions (40 °C and 25 MPa). Inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis on the Pd/Al 2 O 3 catalysts before and after extraction confirmed the removal of palladium from the catalytic supports. Up to 40% of palladium was extracted from the commercial supported catalysts with full recovery of the original alumina support. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Combination of miniemulsion polymerisation and sol-gel method for catalyst tailoring. • A Pd/SiO 2 catalyst with hierarchical micro-, meso- and macroporosity is prepared. • Catalyst structure withstands pressure conditions in the H 2 O 2 direct synthesis. Abstract The production of hydrogen peroxide H 2 O 2 , as an important commodity chemical, attires the attention towards greener processes such as the direct synthesis from hydrogen H 2 and oxygen O 2 , the selectivity being the biggest challenge. Since this reaction is structure-sensitive, the design of appropriate catalysts is required. We propose a novel method to prepare hierarchically porous Pd/SiO 2 catalyst by combination of miniemulsion polymerisation to prepare a Pd-containing latex template and sol-gel synthesis in controlled conditions to tailor the silica porosity. The final material displayed a surface area of 711 m2 g−1 and a total pore volume of 0.93 cm3 g−1. The catalyst was evaluated with different pre-treatments in the direct synthesis of H 2 O 2 , where it exhibited structural resistance at the reaction conditions and a stable selectivity of 46 ± 1% towards H 2 O 2. [ABSTRACT FROM AUTHOR]

Abstract: 1,3‐Bis(mesityl)imidazolium tetraphenylborate (IMesH+ BPh4−) can be synthesized in one step by anion metathesis between the corresponding imidazolium chloride and sodium tetraphenylborate. In the presence of 2‐isopropylthioxanthone (sensitizer), an IMes N‐heterocyclic carbene (NHC) ligand can be photogenerated under irradiation at 365 nm through coupled electron/proton transfer reactions. By combining this tandem NHC photogenerator system with metathesis inactive [RuCl2(p‐cymene)]2 precatalyst, the highly active RuCl2(p‐cymene)(IMes) complex can be formed in situ, enabling a complete ring‐opening metathesis polymerization (ROMP) of norbornene in the matter of minutes at room temperature. To the best of our knowledge, this is the first example of a photogenerated NHC. Its exploitation in photoROMP has resulted in a simplified process compared to current photocatalysts, because only stable commercial or easily synthesized reagents are required. [ABSTRACT FROM AUTHOR]

We present for the first time the aqueous emulsion radical polymerization of cardanol derived methacrylic monomer (CAMA) in order to pave the way for the replacement of styrene. This monomer was synthesized in two-step routes by epoxidation of cardanol prior to methacrylation. Polymerization of CAMA was studied both in toluene solution and in aqueous emulsion. Radical aqueous emulsion homo- and co-polymerization of CAMA with methyl methacrylate (MMA) were performed with sodium dodecyl sulfate as surfactant. Stable latexes were obtained with particle size between 25 and 75 nm. CAMA and MMA conversions were monitored versus time. Influence of radical initiator was studied on gel content, showing transfer to monomer in the case of persulfate as initiator. Glass transition temperature of homoPoly(CAMA) was determined and is suitable for coating application. Photo-crosslinking was performed by thiol-ene chemistry and allowed yielding cross-linked biobased aromatic coatings. [ABSTRACT FROM AUTHOR]

The reactivities of two model molecules, 3-methylthiophene (3MT) and benzothiophene (BT), representative of those contained in a FCC gasoline, was investigated over two Ni-promoted MoS 2 (NiMoS) bulk catalysts prepared according to two synthesis procedures, a metathesis-like one (NiMoS-M) and an innovative one including an in-situ Ni promotion (NiMoS-NG). The second procedure led to smaller NiMoS particles with a narrower size distribution and higher Ni promotion rate. Differences in the activity of the catalysts were observed for the transformation of 3MT and BT. BT was more reactive than 3MT over NiMoS-M whereas the reactivity of both sulfur molecules became similar over NiMoS-NG. The kinetic modeling indicated a higher adsorption constant of 3MT over NiMoS-NG than NiMoS-M and similar adsorption constant of BT on both catalysts. The results have been interpreted taking into account the differences of the catalyst properties in relation with the mechanisms involved in the transformation of both molecules. [Display omitted] ● Influence of synthesis procedures for NiMoS catalyst properties. ● Innovative synthesis of MoS 2 bulk catalysts with remarkable Ni promotion. ● Strong difference in reactivity of 3-methylthiophene and benzothiophene. ● Importance of coupled "experimental/kinetic modeling" studies. ● Importance of adsorption/reaction mechanisms of sulfur molecules for the catalyst efficiency. [ABSTRACT FROM AUTHOR]

A novel catalyst preparation procedure is proposed in order to enhance the noble metal distribution at low loadings, while controlling the hierarchical porosity of the support material. Thus, a silica-supported platinum catalyst with hierarchical porosity was prepared using a combination of three processes performed in aqueous medium: emulsion polymerisation, sonochemistry and sol-gel synthesis. First, a polystyrene latex template of ca. 130 nm was synthesised by emulsion polymerisation and subsequently decorated with Pt nanoparticles of ca. 2.1 nm by sonochemical reduction of sodium tetrachloroplatinate. Then, the mesoporous silica support was prepared by a two-step acid-base catalysed sol-gel synthesis around the Pt-loaded latex spheres. Materials with specific surface areas and total pore volumes as high as 615 m 2 g −1 and 0.74 cm 3 g −1 , respectively, were obtained. [ABSTRACT FROM AUTHOR]

An ecofriendly and straightforward approach to prepare PNIPAM-functionalized mesoporous hybrid silica materials is described: the use of PEO-b-PNIPAM diblock copolymers, specifically designed to act as efficient structure-directing agents (SDA) in silica synthesis, led directly to functionalized hybrid silica materials, whose mesoporosity was subsequently created by washing the material in water in appropriate conditions. Drug-loaded mesoporous silica materials are usually obtained by impregnating such hybrid materials in a drug-containing organic solvent. To avoid such a step, an alternative strategy for the direct incorporation of a hydrophobic drug (i.e., during the synthesis of the hybrid material) was successfully attempted. Finally, the effect of temperature on the release rate of the drug, which appears to be quite slow, was investigated. [ABSTRACT FROM AUTHOR]

Patterned coatings based on biodegradable crosslinked poly(ester/carbonate) have been prepared by photo-induced ring-opening polymerization of a liquid bifunctional trimethylene carbonate-based monomer using poly(ε-caprolactone) triol as initiator and a guanidine superbase photogenerator activated by irradiation at 385 nm. The influence of various parameters on gel time such as components molar ratios, irradiation time or reaction temperature, has been evaluated by photorheometry. The formulation and experimental conditions offering the shortest gel times were then employed to produce a patterned coating by stereolithography. Sample thickness proves to be independent of irradiation time, but increases with reaction time, thus attesting of a dark polymerization. [Display omitted] • Photo-induced ring-opening polymerization has been employed to prepare coatings. • Liquid formulations containing a bis-cyclic carbonate have been prepared. • Gel times of 1 min were obtained using a PBG releasing TBD under 385 nm. • Patterned coatings have been prepared using a stereolithography apparatus. [ABSTRACT FROM AUTHOR]

Amphiphilic functional copolymers have been successfully synthesized and used for the supercritical CO 2 -mediated design of Pd supported catalysts. First, a new palladium complex soluble in supercritical CO 2 has been prepared by ligand exchange, in Freon 113 or supercritical CO 2 , between an amphiphilic functional copolymer and a metal precursor (palladium acetate Pd(OAc) 2 ). Then, the solubility behavior of this copolymer/Pd II supramolecular complex has been studied in supercritical CO 2 . The amphiphilic functional gradient copolymer used in this work, poly(1,1,2,2-tetrahydroperfluorodecylacrylate- co -acetoacetoxyethylmethacrylate) copolymer (poly(FDA- co -AAEMA)), was purposely synthesized by controlled radical polymerization in trifluorotoluene or in supercritical CO 2 . The fluorinated monomer units (FDA) impart CO 2 -philic properties to the copolymer while the acetoacetoxy monomer units (AAEMA) bring the complexing character to the copolymer. After reduction of the complex under hydrogen atmosphere, well-dispersed small nanoparticles of Pd° (2–6 nm diameter size range) were obtained within the copolymer matrix. The copolymer/Pd II supramolecular complex was also used as an impregnation agent for the preparation of supported catalysts. Thus, a mesoporous silica material was impregnated by the complex in supercritical CO 2 . After reduction, a composite material composed of nanoparticles of Pd° (2–9 nm size) evenly distributed in the pores of the silica matrix was obtained. Finally, the catalytic activity of the prepared Pd°@SiO 2 supported catalyst was evaluated in the Heck reaction. [ABSTRACT FROM AUTHOR]

A versatile approach has been developed to prepare small mesoporous silica particles with simultaneous control of the internal ordered pore structure and the external particle surface. Mixed polyion complex (PIC) micelles are used as silica structure-directing agents: they result from the complexation of a polybase with two polyacid double-hydrophilic block copolymers (DHBC) having either a poly(ethylene oxide) (PEO) based-block or a polyacrylamide (PAM) block. The ionizable block in both DHBC is poly(acrylic acid), which complexes oligochitosan to form the core of the electrostatic complex. By varying the architecture of the PEO-based block (linear or comb-shaped) and the synthesis parameters, it is possible to modulate the pore structure from 3D cage-like to 2D-hexagonal and lamellar mesostructures. Replacing a fraction of the PEO-based polymers with DHBC having a polyacrylamide block that has no affinity for silica is shown to affect silica-micelle interactions and material growth. While the PEO chains interact with silica to form the hybrid interface, the PAM chains act as capping agents and control the external surface of the particles. Increasing the relative amount of PAM-based DHBC leads to the formation of small discrete mesoporous silica particles that are reduced in size to 200 nm. The particle size reduction and particle surface stabilization by PAM chains can be explained by considering not only the existence of a mixed corona of PAM and PEO in PIC micelles but also the differentiated solubility of these two neutral blocks induced by silica condensation. Thus, the present strategy allows independent decrease of the particle size and tuning of its pore structure. [Display omitted] • Eco-friendly synthesis of ordered mesoporous silica using polyion complex micelles of three hydrophilic polymers. • Mixed corona micelles act both as structure-directing agents and as capping agents for small ordered mesoporous particles. • Elucidation of formation mechanisms that lead to independent tuning of particle size and pore structure. [ABSTRACT FROM AUTHOR]

Modification of the biodegradable and renewable poly(lactide) (PLA) to provide functional aliphatic polyesters is highly desirable to meet application requirements. In this context, the objective of this work is to evaluate the possibility of using free-radical substitution as a simple and non-degrading method to yield the desired functional PLA. Halogenation of PLA is carried out in solution and various reaction conditions are evaluated. Halogenated PLAs are characterized by 1H NMR spectroscopy and size exclusion chromatography (SEC) to evaluate the substitution ratios and to check the non-degrading character of the radical modification. Furthermore, reactions on model compounds as well as MALDI-TOF analyses are performed to elucidate the involved mechanism. The combined results prove the free-radical halogenation of PLA in solution to be regioselective with only the ω-halogenated PLA being obtained without main-chain substitution. [ABSTRACT FROM AUTHOR]

Reverse iodine transfer polymerization (RITP) of 1,1,2,2-tetrahydroperfluorodecyl acrylate (FDA) is successfully performed in supercritical carbon dioxide (scCO2) at 70 °C under a CO2 pressure of 300 bar. PolyFDA (PFDA) of increasing molecular weights (from 10 000 to 100 000 g mol−1) is synthesized with good agreement between theoretical, 1H NMR spectroscopy and and size exclusion chromatography/refractive index/right-angle laser-light scattering/differential viscometer (SEC/RI/RALLS/DV)-estimated molecular weights ( [ABSTRACT FROM AUTHOR]

Abstract: This study reported the sonochemical deposition of platinum on the surface of polystyrene beads (PSBs) and the transfer of obtained Pt nanoparticles into a porous silica matrix using the PSB as a sacrificial template. Platinum nanoparticle deposition was ensured by the sonochemical reduction of Pt(IV) at room temperature in latex solutions containing polystyrene beads in the presence of formic acid under Ar or under Ar/CO atmosphere without any additives. After ultrasonic treatments for few hours, well dispersed Pt nanoparticles within the range of 3–5nm deposited on PSB were obtained in both studied conditions. Samples were then mixed with TEOS, dried, and heated at 450°C to ensure the PSB removal from the silica matrix. TEM and SEM results clearly show that final silica pore size is within the same order of magnitude than initial PSB. Finally, platinum decorated silica matrix with chosen pore sizes was successfully prepared. [Copyright &y& Elsevier]

Abstract: The phase behavior of triblock and graft-type poly(dimethylsiloxane) (PDMS)–poly(ethylene oxide) (PEO) copolymer surfactants has been investigated in compressed carbon dioxide (CO2). For this purpose, cloud-point pressures have been measured in the pressure and temperature range from P =10 to 40MPa and from T =293 to 338K. The Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equation of state (EoS) has been applied to model the experimental data in order to better understand the influence of the structure of the copolymers on the phase behavior of the system. The pure-component parameters for PDMS have been fitted originally to PDMS/n-pentane system. These parameters are successfully applied for PDMS in CO2 by adjusting a temperature-dependent binary interaction parameter. The phase behavior of the triblock copolymers was successfully predicted by PC-SAFT. In contrast, the phase behavior of the graft copolymers was difficult to predict accurately at this stage. [Copyright &y& Elsevier]

Abstract: Poly(glycidyl methacrylate-co-butyl methacrylate)/poly(vinylidene chloride-co-methyl acrylate) (poly(GMA-co-BMA)/poly(VDC-co-MA)) composite latexes have been successfully synthesized via a two-stage emulsion polymerization process. In a first step, emulsion copolymerization of GMA and BMA was carried out in optimized conditions (low temperature, neutral pH, starved-feed conditions) to both limit the hydrolysis of epoxy groups and obtain small particle size (typically 30–50 nm size range). Composite latexes were then obtained by a second-stage seeded copolymerization of VDC and MA in the presence of tetrasodium pyrophosphate to control the pH and reach high molecular weight, leading to partial encapsulation of the seed particles (snow-man morphology, in agreement with theoretical expectations). Thermogravimetric analyses performed on the resulting composite particles showed that the epoxy-functionalized seed polymer behaved as an efficient thermal stabilizer of PVDC. [Copyright &y& Elsevier]

The article offers information on poly(dimethylsiloxanes) (PDMS) copolymers and explores its synthesis to functionalized polysiloxanes by radical polymerization. It discusses the synthesis of polysiloxanes using routes such as ring-opening polymerization, polycondensation, and redistribution, and cites some applications based on surface and mechanical properties and thermal stability. It states that PDMS-containing architectured copolymers can be obtained by correct polysiloxane macroinitiator.

Nanofiltration using inorganic membranes was conducted to develop a continuous process in supercritical CO2. Inorganic membranes of various sizes (1, 5, 50, 300 kDa), materials (Al2O3/TiO2/ZrO2, Al2O3/ZrO2/TiO2), and modules (one and three channels) were used for the experiments. The effects of fluid viscosity and density, membrane active layer thickness, number of channels, pore size, and the flux of a fluid were analyzed when supercritical CO2(sc-CO2) passed through the membrane. In the case of PE6100 surfactant, it was confirmed that sc-CO2passed through the membrane at a flow rate and transmembrane pressure (ΔP) greater than 10 mL/min and 0.04 MPa, respectively, although the size of the surfactant was larger than that of the membrane pore. The phenomena were proven to have been caused by the folding effect. In the case of microemulsions using NP-4 and H2O, it was confirmed that water adsorbed on the membrane surface passed through at ΔPgreater than 0.7 MPa. Based on these findings, experiments were conducted to separate microemulsions and dispersions. The experimental results indicated that microemulsions achieved 47% separation efficiency and 90% surfactant recovery efficiency due to the displacement of metal ions through the water adsorbed on the membrane surface. Conversely, dispersions yielded high separation efficiency. Also, the correlation between the contaminant size and the membrane pore size was confirmed through SEM images. [ABSTRACT FROM AUTHOR]

The phase behavior of several commercially available poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) block copolymers (PEO−PPO−PEO or Pluronics L) in compressed carbon dioxide has been investigated within the framework of dry nuclear decontamination. For this purpose, cloud points have been measured in the pressure and temperature range from P= (10 to 40) MPa and from T= (293 to 338) K, respectively. To find a reliable method for surfactant selection, the perturbed-chain statistical association fluid theory (PC-SAFT) equation of state (EoS) has been applied to model the experimental data. The pure-component and the respective homopolymer + CO2binary interaction parameters have been fitted to liquid densities and to homopolymer + CO2binary equilibrium data. The phase behavior of Pluronics L copolymers as a function of concentration, molar mass, and copolymer composition has been predicted very accurately using a constant PEO−PPO binary interaction parameter kPEO-PPO= 0.007. The PC-SAFT model was also successfully applied to Pluronics R copolymers (PPOPEOPPO), although a different kPEO-PPO= −0.018 was required to match the experimental data. The model predictions have shown that Pluronics L copolymers with molar mass M< 2750 g·mol−1and a PEO mass fraction in the copolymer of less than 30 % have sufficiently low cloud-point pressures and are therefore the most suitable for the decontamination process. [ABSTRACT FROM AUTHOR]

Biobased monomers and green processes are key to producing sustainable materials. Cardanol, an aromatic compound obtained from cashew nut shells, may be conveniently functionalized, e.g., with epoxy or (meth)acrylate groups, to replace petroleum-based monomers. Photoinduced polymerization is recognized as a sustainable process, less energy intensive than thermal curing; however, cardanol-based UV-cured polymers have relatively low thermomechanical properties, making them mostly suitable as reactive diluents or in non-structural applications such as coatings. It is therefore convenient to combine them with biobased reinforcements, such as microfibrillated cellulose (MFC), to obtain composites with good mechanical properties. In this work a cardanol-based methacrylate monomer was photopolymerized in the presence of MFC to yield self-standing, flexible, and relatively transparent films with high thermal stability. The polymerization process was completed within few minutes even in the presence of filler, and the cellulosic filler was not affected by the photopolymerization process. [ABSTRACT FROM AUTHOR]

Abstract: The phase behavior of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymers (PEO-PPO-PEO Pluronics) in liquid and supercritical carbon dioxide has been studied by cloud point measurements. It shows that such trade hydrocarbonated surfactants are fairly soluble (0.1wt.%) in carbon dioxide in relatively mild conditions of temperature and pressure (T <65°C, P <30MPa). An empirical model based on the molecular weight of the copolymer has been proposed to predict the pressure–temperature phase diagram for a series of Pluronics (10wt.% of ethylene oxide). Furthermore, the water/CO2 interfacial tension has been measured to investigate the interactions between water and the polar moieties of the surfactants (PEO blocks and hydroxyl end-groups) as well as the interactions between CO2 and the “CO2-philic” moiety of the surfactants (PPO block). An interfacial saturation concentration was evidenced and it was shown to depend on the temperature at a given pressure. The cloud point curves and interfacial tension data are fully consistent with a change in the affinity of the surfactant for CO2 versus pressure and temperature. A correlation between CO2-philic characteristics and surface active properties of the copolymers is given. [Copyright &y& Elsevier]

The article explores the research findings on the synthesis and the application of iodinated derivatives involved in telomerization, iodine transfer polymerization, and reverse iodine transfer polymerization. The Daikin Co. pioneered in the late 1970s the use of perfluoroalkyl iodides or diiodoperfluoroalkane as chain transfer agents in the controlled radical polymerization of fluorinated monomers.