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A middle-chain cleavable telechelic poly(oligoethylene glycol) methyl ether acrylate) (MCCT-POEGA-Br) was synthesized by single-electron transfer living radical polymerization (SET-LRP) initiated from an acetal-containing hydrophobic sequence-defined difunctional initiator. In aqueous medium, above a certain concentration, this hydrophilic homopolymer self-assembled into nanogel-like large micelles that exhibit an encapsulating capacity for both hydrophobic and hydrophilic cargo. The sequence-defined cleavage pattern encoded in the initiator residue allowed precise middle-chain cleavage, leading to quantitative disassembly of the corresponding nanoobjects. Dye release studies performed in an acidic environment demonstrated the potential of this new design concept in the preparation of pH-responsive nanocarriers. In addition, fluorescently tagged nanoassemblies could also be obtained via the thio-bromo "click" modification of MCCT-POEGA-Br prior to self-assembly. This strategy may provide facile access to a diversity of multistimuli-responsive nanocarriers based on commercially available hydrophilic monomers and sequence-defined difunctional initiators synthesized by this simple design strategy.

Branched polyesters with acid degradable and oxidation responsive β-thiopropionate groups have been obtained by lipase catalyzed polycondensation of diester and hydroxyester monomers from heptanal, a castor oil derivative. Their polymerization behavior has been investigated and poly(ethylene glycol)-b-poly(β-thioether ester) amphiphilic block copolymers have been obtained. SEC, NMR and FTIR have been employed to confirm the structure of the polymers and copolymers and DSC and TGA have been used to characterize their thermal properties. The block copolymers containing aliphatic pendant moieties self-assemble into micelles in aqueous solution, showing potential application as dual responsive systems in drug delivery.

The synthesis of a partially renewable hydroxyl hyperbranched polyester: poly(10,11-dihydroxyundecanoic acid) (PDHU), by polycondensation using CALB as catalyst, has been described. The synthesized polymers were structurally characterized in detail, using model compounds previously synthesized, by 1H, 13C and 19F NMR. The synthesis of amphiphilic copolymers by incorporation of mPEG moieties and utilizing CALB, was carried using two methods: by copolymerization of mPEG-OH and 10,11-dihydroxyundecanoic to produce block hyperbranched copolymers, and grafting onto hydroxyl groups of linear and hyperbranched PDHU, mPEG containing carboxylic acid. The microstructure of block and grafted copolymers was determined in detail by NMR spectroscopy by using models and 1H-13C heteronuclear bidimensional correlations. The self-assembly of these amphiphilic polyesters form well-defined multimolecular micelles ranging 100–300 nm in very diluted aqueous solutions, showing potential application in drug delivery among other applications.

The fluorinated alcohol 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) is an especially effective solvent for solubilizing a wide range of polymers. However, the performance of HFIP as SET-LRP solvent has classically been questioned due to its poor Cu(I)X disproportionating properties. Taking advantage of the fast and quantitative disproportionation of Cu(I)X in water, SET-LRP in organic solvent/water mixtures rids the organic solvent of mediating this fundamental event. Here, the Cu(0) wire-catalyzed SET-LRP synthesis of well-defined poly(methyl acrylate)s and poly(butyl acrylate)s with narrow molecular weight distribution and near perfect bromine chain end functionality is reported in HFIP/water mixtures. The results reported here support the potential of HFIP/water mixtures in the preparation of more complex architectures including polymers with dual control over molecular weight and tacticity. Since HFIP is also a classic solvent for the denaturation of proteins this SET-LRP system is also expected to find applications in the grafting of protein.

A simple synthetic route is used for the preparation of hydroxyl functionalized polyesters from an AB-type monomer carrying an epoxy and carboxylic acid group. A systematic study of the reaction conditions suggested that tetrabutylphosphonium bromide was the better polymerization catalyst to obtain the highest conversion of linear polymers with moderate molecular weights. Enzymatic catalyst (CALB), in contrast, yielded branched polymers with polyether units. The synthesized polymers were structurally characterized in detail, using model compounds previously synthesized, by 1H, 13C, and 19F NMR. Polyesters were characterized by FTIR, SEC, DSC and TGA too. The post-polymerization modification of the reactive hydroxyl sites present along the polymer backbone with N-Boc protected l -phenylalanine and l -serine was essayed to test the ability of these polyesters to prepare polymer bioconjugates.

Cu(0) wire-catalyzed single electron transfer–living radical polymerization (SET-LRP) of (−)-menthyl acrylate, a biobased hydrophobic monomer, was investigated at 25 °C in ethanol, isopropanol, ethyl lactate, 2,2,2-trifluoroethanol (TFE), and 2,2,3,3-tetrafluoropropanol (TFP). All solvents are known to promote, in the presence of N ligands, the mechanistically required self-regulated disproportionation of Cu(I)Br into Cu(0) and Cu(II)Br2. Both fluorinated alcohols brought out their characteristics of universal SET-LRP solvents and showed the proper polarity balance to mediate an efficient polymerization of this bulky and hydrophobic monomer. Together with the secondary alkyl halide initiator, methyl 2-bromopropionate (MBP), and the tris(2-dimethylaminoethyl)amine (Me6-TREN) ligand, TFE and TPF mediated an efficient SET-LRP of MnA at room temperature that proceeds through a self-generated biphasic system. The results presented here demonstrate that Cu(0) wire-catalyzed SET-LRP can be used to target polyMnA...

Block copolymers containing poly(trimethylene carbonate) (PTMC) middle block and poly(furfuryl methacrylate) PFMA end blocks were synthesized through sequential organocatalytic ring opening polymerization (ROP) of trimethylene carbonate and thermal and photoinitiated metal-free atom transfer radical polymerizations (ATRP) of furfuryl methacrylate. The thermal and mechanical properties of the triblock copolymers were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamical mechanical analysis (DMA). The crosslinking via Diels-Alder (DA) reaction between the furan groups of the block copolymers and bismaleimide and bisitaconimide was proved by FTIR and DSC and the thermoreversibility properties of the crosslinked polymer were subsequently investigated using DSC and solubility testing.

Single electron transfer-living radical polymerization (SET-LRP) provides excellent control over polymer chain-end functionality. The chain ends of poly(butyl acrylate) (PBA), prepared by biphasic SET-LRP in an acetone/water mixture using a non-activated Cu(0) wire/TREN/Cu(II)X2 catalytic system, could not be reacted quantitatively using a biphasic reaction mixture of potassium acrylate (KA) in acetonitrile at 75 °C. This procedure was previously successfully applied to poly(methyl acrylate). The PBA chain ends showed lower reactivity due to their higher hydrophobicity and sterically hindered nature. However, the chain extension of α-bromo and α,ω-dibromo PBA with a few monomeric units of MA dramatically changed the reactivity of PBA. Thus, acrylate-functionalized macromonomers and telechelics based on PBA could be successfully prepared by merging biphasic SET-LRP, chain extension with MA and heterogeneous esterification with KA in acetonitrile at 75 °C. This three step methodology, that can be simplified by carrying out two or even three steps in one pot, is expected to become a general route for the preparation of acrylate-functionalized polyacrylates derived from monomers with hydrophobic and sterically hindered substituents.

The high bromine chain end functionality of polyacrylates synthesized by single electron transfer living radical polymerization (SET-LRP) mediated by TREN in a biphasic acetone–water mixture containing Cu(II)Br2 can be exploited to introduce specific functional groups to the chain-ends of these polymers. Here, the α-bromoester end groups of poly(methyl acrylate) (PMA) synthesized in this biphasic SET-LRP system using non-activated Cu(0) wire as catalyst were reacted also under heterogeneous biphasic conditions with potassium acrylate to yield PMA macromonomers and telechelics with α- and α,ω-acrylate chain ends. The reagents used in both steps are air insensitive and inexpensive. 500 MHz 1H NMR, GPC and MALDI-TOF analyses in combination with the thio-bromo “click” reaction were used to confirm the high efficiency of this two-step protocol. The reactive nature of these macromonomers by the preparation of a PMA-g-PMA more complex architecture was also demonstrated.

Biphasic-binary mixtures of 2,2,2-trifluoroethanol (TFE) or 2,2,3,3-tetrafluoropropanol (TFP) with water were used as reaction media to synthesize well-defined poly(methyl acrylate) (PMA) with chain end functionality close to 100% by SET-LRP. Non-activated Cu(0) wire was used as a catalyst, taking advantage of the Cu(0)-activation property that these fluorinated alcohols possess. Biphasic-binary mixtures of water, containing a ligand and Cu(II)Br2 either generated by disproportionation of Cu(I)Br or externally added, and an organic solvent, containing a monomer and a polymer, were studied. Two N-ligands were investigated: the classic tris(2-dimethylaminoethyl)amine (Me6-TREN) and tris(2-aminoethyl)amine (TREN), as a more economically attractive alternative for technological purposes. The results reported here support the replacement of Me6-TREN by TREN, taking into account the fact that the latter requires small loadings of an externally added Cu(II)Br2 deactivator and a ligand in the water phase to mediate a living radical polymerization process. Both catalytic systems ensure efficient SET-LRP processes with first order kinetics to high conversion, linear dependence of experimental Mn on conversion, narrow molecular weight distribution, and near-quantitative chain end functionality.

Depending on the order of their addition to the reaction mixture, acrylates can undergo SET-LRP or dibromination by Cu(II)Br2 and spontaneously dehydrohalogenate to provide the corresponding highly reactive α-bromoacrylate monomer and Michael acceptor.

Intensive research has recently been carried out to synthesize non-isocyanate polyurethanes (NIPUs) from five-membered cyclic carbonates and amines as a sustainable route to industrial relevant polyurethanes. Herein, an activated disubstituted cyclic carbonate and methyl ester containing monomer CE was prepared using castor oil based heptanal and CO 2 . Good results for the catalytic cycloaddition have been obtained using renewable sugar cane bagasse in combination with TBAB, and this system has been shown to be recyclable. A novel poly(amide-hydroxyurethane) ( PAHU ) was obtained by bulk ring-opening and amidation polymerization of high reactive CE with 1,6-diaminohexane at low temperature and in absence of catalyst. PAHU contains aliphatic pendant moieties allowing its self-assembling into nanoparticles in aqueous solution, showing potential application in catalysis or drug delivery among other applications.

The precise synthesis of polymers derived from alkyl lactate ester acrylates is reported for the first time. Kinetic experiments were conducted to demonstrate that Cu(0) wire-catalyzed single electron transfer-living radical polymerization (SET-LRP) in alcohols at 25 °C provides a green methodology for the LRP of this forgotten class of biobased monomers. The acrylic derivative of ethyl lactate (EL) solvent and homologous structures with methyl and n-butyl ester were polymerized with excellent control over molecular weight, molecular weight distribution, and chain-end functionality. Kinetics plots in conventional alcohols such as ethanol and methanol were first order in the monomer, with molecular weight increasing linearly with conversion. However, aqueous EL mixtures were found to be more suitable than pure EL to mediate the SET-LRP process. The near-quantitative monomer conversion and high bromine chain-end functionality, demonstrated by matrix-assisted laser desorption ionization time-of-flight analysis, further allowed the preparation of innovative biobased block copolymers containing rubbery poly(ethyl lactate acrylate) poly(ELA) sequences. For instance, the poly(ELA)- b-poly(glycerol acrylate) block copolymer self-assembled in water to form stable micelles with chiral lactic acid-derived block-forming micellar core as confirmed by the pyrene-probe-based fluorescence technique. Dynamic light scattering and transmission electron microscopy measurements revealed the nanosize spherical morphology for these biobased aggregates.

A set of (poly-α-methylene-γ-butyrolactone)–co-(poly-δ-decalactone)–co-(poly-α-methylene-γ-butyrolactone) (PMBL-co-PDL-co-PMBL) ABA block copolymers containing different stimuli cleavable groups at the central point of the poly(δ-decalactone) (PDL) block were synthesized by a combination of Ring Opening Transesterification Polymerization (ROTEP) of DL, diol end-group functionalization as α-bromoester and Atom Transfer Radical Polymerization (ATRP) of α -methylene-γ-butyrolactone (MBL). Diols containing acetal, spiroacetal, thioacetal and disulphide units were used as initiators for the bulk room temperature controlled polymerization of δ-decalactone (DL) using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst. PDL diols were functionalized in a one-pot two-steps procedure using N-(2-bromoisobutyryl)imidazole (BiB-Im). The resulting macroinitiators were chain extended by atom transfer radical polymerization (ATRP) in DMF at 50 °C using MBL as methacrylic-like monomer and the conventional CuCl/CuCl2/2,2′-bipyridine catalyst system. The cleavage behaviour of the copolymers under reductive, acidic and photooxidative conditions has been studied and the resulting AB block copolymers structurally characterized.

Polyurethanes and polyureas from renewable castor oil-derived 10-undecenoic acid were synthesized using the AB-type self-condensation approach. ω-Hydroxy- or ω-amino methyl carbamate ester precursor monomers were prepared under mild conditions from cysteamine methyl carbamate by thiol-ene addition. Synthesis of cysteamine carbamate and the self-condensable monomers derived of 10-undecenol or 10-undecenylamine was studied by using different synthetic conditions. Two different polymers, a polyurethane and a polyurea, were prepared using conventional catalysts thus following a non-isocyanate route. The proposed synthetic approach constitutes a general route that allows for the easy preparation of methyl carbamate monomers not only from renewable (limonene, myrcene, geraniol, etc.), but also from petroleum-derived unsaturated substrates.

A series of monofunctional benzoxazine monomers with terminal unsaturated alkyl chains was synthesized from fatty acid-derived renewable compounds: 10-undecenoic acid, 4-pentenoic acid and 10-undecen-1-ol. The monofunctional monomers were dimerized by self-metathesis under mild conditions. Different metathesis catalysts and conditions were tested to obtain the desired dimers in good yields and purity that were characterized by 1H, 13C NMR and ESI-TOF. The structure, properties affecting processing ability and thermal polymerization behavior of the resulting α,ω-bis-benzoxazines were studied. The properties of the obtained flexible materials were evaluated by DSC, TGA, DMTA and contact angle measurements.

The synthesis of oxidation-responsive biodegradable amphiphilic block copolymers by Candida Antarctica Lipase B (CALB)-catalyzed self-polycondensation of 11-((2-hydroxyethyl)-thio)undecanoic acid (TEHA) initiated by methoxy polyethyleneglycol (mPEG-OH) of different molecular weights has been described. SEC and mono and bidimensional NMR have been used to confirm the molecular weight and structure of the polymers and copolymers. DSC and TGA have been employed to characterize their thermal properties. The oxidation behaviour in front of H2O2 as well as the structure of the oxidized products has been established using NMR, FTIR and Raman spectroscopies. The different block copolymers could self-assemble to form nanosized micelles in aqueous solution with low critical micelle concentration (CMC), showing potential application as dual responsive systems in drug delivery. Micellar characteristics were investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). These micelles are prone to undergo a H2O2-triggered disassembly due to the oxidizable thioether groups in the hydrophobic core. Nile Red was used as model for hydrophobic drugs to test the oxidative triggered release of a copolymer, which showed progressive release in few hours upon the addition of H2O2.

This work reports a series of versatile post-polymerization modifications of an aliphatic functional polyester obtained by enzymatic polycondensation of dimethyl 2,9-dibromosebacate and 1,10-decanediol, both derived from castor oil. The alkyl halide functionality has shown to react with thiols, amines and carboxylic acids under mild conditions obtaining high modification degrees. Moreover, functionalization using NIPAAm-COOH terminated polymer has been carried out.

A series of monofunctional benzoxazine monomers with terminal unsaturated alkyl chains were synthesized from two renewable platform chemicals: 10-undecenoic and 4-pentenoic acids. The monofunctional monomers were dimerized under mild conditions by hydrosilylation using two difunctional silanes. Different hydrosilylation conditions and catalysts were tested in order to produce the desired dimmers in good yields and high purity. The structure, properties affecting processing ability and thermal polymerization behavior of the resulting α,ω- bis -benzoxazines were studied. The properties of the resulting flexible materials were evaluated by DSC, TGA, DMTA and CA.

A novel biobased α,ω-diene bearing a thermally curable benzoxazine group is synthesized and polymerized via acyclic diene metathesis (ADMET) using Hoveyda–Grubbs second generation catalyst. The benzoxazine-containing diene monomer was designed based on 10-undecenoic acid, a castor oil derived platform chemical. The Mn and crosslinker content can be modulated by using a monofunctional comonomer to end-cap polymer chains. Differential scanning calorimetry was used to demonstrate that obtained thermoplastic prepolymers are able to yield thermosets after thermally activated ring opening polymerization just simply by heating up to around 200 °C. Thermal and mechanical properties of the cured polybenzoxazines are also discussed.

The synthesis and characterization of fully biobased ABA triblock copolyesters from PLA and castor oil derivatives are described. The synthetic strategy uses a dihydroxy telechelic polyester as a macroinitiator for the ring opening polymerization of l -lactide. This macroinitiator was obtained from a sulfur-containing hydroxyacid derivative of 10-undecenoic acid, which undergoes self-polycondensation with low amounts of biobased 1,4-butanediol, enables the obtention of two prepolymers of different weight. Two series of triblock copolyesters with different percentage of PLA contents were prepared and the resulting thioether-bearing copolyester oxidized to polysulfones. Both series of copolyesters showed improved thermal stability, decrease of crystallinity and a similar hydrophilicity with respect to the PLA homopolymer.

DOI: 10.1021/acs.biomac.7b00197 URL: http://pubs.acs.org/doi/abs/10.1021/acs.biomac.7b00197 Filiació URV: SI Single electron transfer-living radical polymerization (SET-LRP) represents a robust and versatile tool for the synthesis of vinyl polymers with well-defined topology and chain end functionality. The crucial step in SET-LRP is the disproportionation of the Cu(I)X generated by activation with Cu(0) wire, powder, or nascent Cu(0) generated in situ into nascent, extremely reactive Cu(0) atoms and nanoparticles and Cu(II)X2. Nascent Cu(0) activates the initiator and dormant chains via a homogeneous or heterogeneous outer-sphere single-electron transfer mechanism (SET-LRP). SET-LRP provides an ultrafast polymerization of a plethora of monomers (e.g., (meth)-acrylates, (meth)-acrylamides, styrene, and vinyl chloride) including hydrophobic and water insoluble to hydrophilic and water soluble. Some advantageous features of SET-LRP are (i) the use of Cu(0) wire or powder as readily available catalysts under mild reaction conditions, (ii) their excellent control over molecular weight evolution and distribution as well as polymer chain ends, (iii) their high functional group tolerance allowing the polymerization of commercial-grade monomers, and (iv) the limited purification required for the resulting polymers. In this Perspective, we highlight the recent advancements of SET-LRP in the synthesis of biomacromolecules and of their conjugates.

A novel and efficient strategy for the synthesis of nonisocyanate polyurethanes has been developed via thiol–ene self-photopolymerization. An aliphatic thiol–ene carbamate monomer (allyl(2-mercaptoethyl)carbamate, AMC) was synthesized by a one-step synthesis procedure, from cysteamine and allyl chloroformate. The urethane group was therefore incorporated directly into the monomer precursor, avoiding the problems associated to toxic isocyanates. AMC was successfully stabilized with the radical inhibitor pyrogallol (1% wt). In addition, the use of phenyl phosphonic acid as coadditive allowed its stabilization for lower concentrations of pyrogallol (0.1% wt). AMC was directly transformed into thermoplastic polyurethane (TPU) through thiol–ene photopolymerization by UV-irradiation at 365 nm. The obtained TPU presented semi-crystalline nature and very high thermal stability (T5% ∼325 °C). It was found that high concentrations of pyrogallol decreased the reaction rate and final conversion of photopolymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3017–3025

3-Phenyl-3,4-dihydro-2H-1,3-benzoxazine (m1) underwent cationic ring opening polymerization using BF3·OEt2 in alcoholic solution under mild conditions. The polymerization of m1 proceeds through an intermediate hemiaminal ether leading mainly to the formation of polybenzoxazines with diphenylmethane bridges, and not only the classical Mannich-type ones. During the first stages of the reaction, low-molecular weight soluble oligomers containing benzoxazine rings are formed. At longer polymerization times, the propagation proceeds conventionally through the phenolic active sites. This polymerization mechanism is extensible to other substituted 3-phenyl-3,4-dihydro-2H-1,3-benzoxazines but fails in the case of 3-alkyl-3,4-dihydro-2H-1,3-benzoxazines or when the phenyl group in Position 3 have a substituent in the p-position. Spectroscopic studies and kinetic experiments using model reactions and deuterium labeled benzoxazines, allow proposing a plausible different polymerization mechanism. These soluble benzoxazine-containing polymers can be conveniently processed and impregnated on appropriate substrates before underwent crosslinking producing materials with comparable properties to those of conventional bis-benzoxazines. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5075–5084

The benzoxazines of three naturally occurring phenylpropanoid phenols: ferulic, coumaric, and phloretic acids, and their esters are described. Benzoxazines with conjugated unsaturated chains exhibit unusual poor thermal stability and degrade partially at the polymerization temperature making necessary the use of a catalyst (BF3.Et2O) to low the polymerization temperature and prevent degradation. Polybenzoxazines are prepared thermally and characterized by DSC and TGA techniques. The resulting materials have superior Tgs when compared with those prepared from an unsubstituted monofuctional benzoxazine due to the additional crosslinking through the ester and carboxylic moieties. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4894–4903

A set of thermoplastic polyurethanes is synthesized, combining undecylenic acid-derived telechelic diols as soft segments and 1,4-butanediol/4,4'-methylenebis(phenylisocyanate) as a hard segment (HS). These polymers are fully chemically and physically characterized by means of NMR and Fourier transform IR (FTIR) spectroscopy, size-exclusion chromatography (SEC), DSC, thermogravimetric analysis (TGA), tensile testing, and contact angle measurements. The obtained results reveal that both the molecular weight of the diol and the HS content greatly influence the physical and mechanical properties of these polymers. In addition, given the potential use of these materials for biomedical applications, hydrolytic degradation, their biocompatibility using a human fibroblast cell line, and performance as drug delivery carriers are evaluated.

There is no doubt that nature offers an abundance of opportunities to polymer chemists for shaping structural and functional polymers in its wide variety of raw materials. Nowadays, plant oils and derivatives are in the spotlight of polyurethane technology and the design of novel biobased polyols derived from them is an active area of research. The contribution of this technology to sustainable development must go further than simply exploit renewable feedstock, and therefore must be aware of efficient click-chemistry transformations exemplified by thiol-ene/yne couplings. Within this contribution, these biobased materials, together with thiol-ene/yne couplings are presented as a perfect ecofriendly combination to prepare hydroxyl building blocks for polyurethane technology.

10.1016/j.polymer.2012.05.044 This work concerns the investigation of porous polybenzoxazines based on the non-toxic renewable diphenolic acid. The approach described relies on the in situ generation of foaming agent (CO2) during the thermal curing. For this purpose, the previously synthesized benzoxazine monomer from diphenolic acid was thermally polymerized at different temperatures. As the beginning of decarboxylation is about 200 °C, we selected five foaming temperatures (Tf) ranging from 190 to 230 °C. The influence of the foaming temperature on the cellular structure and its dependency on final properties is discussed.

A polybenzoxazine / polysiloxane hybrid has been prepared by sol-gel process and ring-opening polymerization. For this purpose, first a functionalized benzoxazine was synthesized from bisphenol A, paraformaldehyde and 3(trimethoxysilyl) propylamine, with initial molar ratio 1:4:2, and 95% yield. The structure of the monomer was characterized by Fourier Transform Infrared, Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The sol-gel process and curing behavior have been studied by FTIR spectroscopy and Differential Scanning Calorimetry (DSC). The Dynamic Mechanical Analysis (DMTA) of the hybrid material(Bz-PSi) showed higher Tg and storage modulus respect to the conventional polybenzoxazine (Bz-BA). Also, the Thermogravimetric Analysis (TGA) revealed better thermal stability. The high Limiting Oxygen Index (LOI) values (about LOI = 32)confirmed similar effective flame retardance properties of the hybrid material respect conventional benzoxazine. Fil: Spontón, Marisa Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Estenoz, Diana Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Ligadas, G.. Universitat Rovira I Virgili; España Fil: Ronda, J.. Universitat Rovira I Virgili; España Fil: Galià, M.. Universitat Rovira I Virgili; España Fil: Cádiz, V.. Universitat Rovira I Virgili; España

The novel benzoxazine monomers, DPA-Bz and MDP-Bz from renewable diphenolic acid (DPA), which mimics the structure of bisphenol A (BPA), were synthesized by traditional approaches. The structure and purity of the monomers was confirmed by FTIR, 1H NMR, and 13C NMR spectra. The thermally activated polymerization of the MDP-Bz and DPA-Bz afforded thermosetting polybenzoxazines with higher Tg's, 270 °C and 208 °C respectively, and higher crosslinking density compared to BPA-Bz, due to the transesterification or esterification reactions occurred during curing process. These reactions are in accordance with the number of independent reactions determined analyzing by SVD the chemical rank of the IR spectra data matrices recorded along the homopolymerization reactions monitored at 200 °C. Spectral and concentration profiles of the active chemical species involved in these processes were obtained by MCR-ALS. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Natural vegetable oils have been transformed in polymers following three main routes. The first is the direct polymerization through the double bonds of the fatty acid chain. The cationic copolymerization of soybean oil with styrene, divinylbenzene, and different amounts of styrenic monomers containing Si allows producing materials with improved mechanical and flame retardant properties. The second route is the functionalization of the triglyceride double bonds to introduce readily polymerizable groups: The singlet oxygen photoperoxidation-dehydration of the allylic positions of the high oleic sunflower oil allows producing enone-containing triglycerides that are chemically crosslinked with aromatic diamines through aza-Michael reactions. At high temperatures, this curing reaction proceeds through a complex mechanism leading to quinoline moieties. This new crosslinking approach can be also applied to aldehyde containing triglycerides. The third route consists of using plant oil-derived chemicals like 10-undecenoic acid to produce tailor made monomers. Acyclic diene metathesis polymerization has been applied to allyl 10-undecenoate, 10-[2',5'-bis(10-undecenoyloxy)phenyl]-9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide, and 1,3-bis(10-undecenoyl)glycerol to prepare a set of polyesters with different phosphorus and hydroxyl contents. Moreover thiol-ene "click" coupling of allyl 10-undecenoate with mercaptoethanol, 3-mercaptopropanoic acid, and 3-mercaptopropyltrimethoxysilane has been used to produce difunctional telechelic polyesters.

A series of poly(ether urethane) networks were synthesized from polyether polyols obtained by ionic-coordinative polymerization of epoxidized methyl oleate (EMO) using 4,4′-methylenebis(phenyl isocyanate) or l-lysine diisocyanate as coupling agents. Moreover, a variety of segmented poly(ether urethane) networks with different hard segment contents were obtained using 1,3-propanediol as the chain extender. The materials were characterized by differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and tensile properties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

DOPO-containing benzoxazine, which could not be prepared by the traditional approaches, was successfully prepared from phenol, aniline and DOPO by a three-step procedure. The first step is the condensation of 2-hydroxybenzaldehyde with aniline, forming an intermediate imine. The second step is the addition of DOPO to the imine resulting a secondary amine. The third step is the ring closure condensation leading to DOPO-containing benzoxazine. All these structures were confirmed by 1D and 2D NMR spectra. The curing of mixtures of DOPO-containing benzoxazine and benzoxazine of Bisphenol A has been studied. In the samples the molar ratio of benzoxazine monomers was varied to achieve different phosphorus content. The phosphorus-containing polybenzoxazines have been characterized by dynamicmechanical thermal analysis and thermogravimetric analysis. Limiting oxygen index values indicate good flame retardant properties. Fil: Spontón, Marisa Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina. Universitat Rovira I Virgili; España Fil: Ligadas, G.. Universitat Rovira I Virgili; España Fil: Ronda, J. C.. Universitat Rovira I Virgili; España Fil: Galià, M.. Universitat Rovira I Virgili; España Fil: Cádiz, V.. Universitat Rovira I Virgili; España

The development of a novel nucleophilic thio-bromo “Click” reaction, specifically base-mediated thioetherification of thioglycerol with α-bromoesters, is reported. Combination of this thio-bromo click reaction with subsequent acylation with 2-bromopropionyl bromide provides an iterative two-step divergent growth approach to the synthesis of a new class of poly(thioglycerol-2-propionate) (PTP) dendrimers. This approach is demonstrated in the rapid preparation of four generation (G1–G4) of PTP dendrimers with high-structural fidelity. The isolated G1–G4 bromide-terminated dendrimers can be used directly as dendritic macroinitiators for the synthesis of star-polymers via SET-LRP. Additionally, the intermediate hydroxy-terminated dendrimers are analogs of other water-soluble polyester and polyether dendrimers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3931–3939, 2009

The effect of Cu(0) wire dimensions on the Cu(0) wire/Me6-TREN-catalyzed heterogeneous single-electron transfer living radical polymerization (SET-LRP) of methyl acrylate (MA) initiated with methyl 2-bromopropionate (MBP) in DMSO at 25 °C was analyzed by kinetic experiments. These kinetic results were compared with those of Cu(0) powder/Me6-TREN-catalyzed SET-LRP. Both wire and powder produce perfect SET-LRP with a first-order rate of polymerization in growing species up to 100% conversion. Nevertheless, Cu(0) wire experiments demonstrated SET-LRP with greater perfection, allowing for the accurate determination of the external rate order (vis-a-vis surface area) for heterogeneous Cu(0) catalyst and accurate prediction of kpapp from wire dimension. Cu(0) wire also exhibited a significantly greater control of molecular weight distribution than Cu(0) powder. The combined advantages of easier catalyst preparation, handling, predictability, tunability, simple recovery/recycling, and enhanced control of molecul...

In order to assess the role of the solvent mediating the disproportionation of Cu(I)X into Cu(0) and Cu(II)X2 during SET-LRP, a series of polymerizations of methyl acrylate initiated with methyl 2-bromopropionate and catalyzed by Cu(0)/Me6-TREN at 25 °C in DMSO, MeCN, and their mixtures were investigated. These polymerizations proceed in a dissimilar manner. SET-LRP of MA in DMSO, a solvent that mediates disproportionation, was exemplary of “ultrafast living radical polymerization” with complete conversion in 45 min following the expected first-order kinetics and providing perfect fidelity of the structure of the polymer chain ends. When the polymerization was performed in MeCN, a solvent in which Cu(I)X species do not disproportionate, it displayed nonlinear first-order kinetics with a poor retention of the bromine chain end functionality. The lack of first-order kinetics and decrease of chain end functionality with conversion indicate a nonliving polymerization in MeCN. Increasing the concentration of D...

Cu(I)Br/Μe 6 .TREN species are unstable and disproportionate into metallic Cu(0) and Cu(II)Br 2 /Μe 6 -TREN in DMSO, whereas in toluene are stable and do not undergo disproportionation, at least at 25 °C. To estimate the role of the disproportionating solvent in single electron-transfer living radical polymerization (SET-LRP) a comparative analysis of Cu(0)/Me 6 -TREN-catalyzed polymerization of MA initiated with methyl 2-bromopropionate at 25 °C was performed in DMSO and toluene. A combination of kinetic experiments and chain end analysis by 500-MHz 1 H NMR spectroscopy was used to demonstrate that disproportionation represents the crucial requirement for a successful SET-LRP of MA at 25 °C. In DMSO a perfect SET-LRP occurs and yields close to 100% conversion in 45 min. A first order polymerization in growing species up to 100% conversion and a PMA with perfectly functional chain ends are obtained. However, in toluene within 17 h only about 60% conversion is obtained, the polymerization does not show first order in growing species and therefore is not a living polymerization. Moreover, at 60% conversion the resulting PMA has only 80% active chain ends.

The Cu(0)/Me6-TREN-catalyzed single-electron transfer mediated living radical polymerization (SET-LRP) of methyl acrylate in the presence of the classic 4-methoxyphenol free radical inhibitor was investigated. Kinetic experiments, combined with 1H NMR, and MALDI-TOF MS analysis of the resulting polyacrylates demonstrated that SET-LRP is a robust synthetic method that does not require the purification of the monomers to remove the radical inhibitor. It is anticipated that these results will contribute to the expansion of technological and fundamental applications of SET-LRP since it allows the synthesis of polymers with a structural perfection that previously was not accessible by any other method, starting from unpurified monomers, solvents, initiators, and ligands. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3174–3181, 2008

Single-electron transfer living radical polymerization (SET-LRP) proceeds by an outer-sphere single-electron transfer mechanism that induces a heterolytic bond cleavage of the initiating and propagating R-X (where X = Cl, Br, and I) species. Therefore, unlike the homolytic bond cleavage mechanism claimed for ATRP, SET-LRP is expected to show a small dependence of the nature of the halide group on the apparent rate constant of activation. This means the R-X with X = Cl, Br, and I must all be efficient initiators for SET-LRP and no chain transfer must be observed in the case of initiators with X = Br and I. Here, we report the SET-LRP of methyl acrylate initiated with the alkyl chlorides methyl-2-chloropropionate (MCP) and chloroform (CHCl3) and catalyzed by Cu(0)/Me6-TREN/CuCl2 in DMSO at 25 °C. A combination of kinetic and structural analysis was used to elucidate the MCP and CHCl3 initiating behavior under SET-LRP conditions, and to demonstrate the very small dependence of the SET-LRP apparent rate constant of propagation on X while providing polymers with well defined architecture. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4917–4926, 2008

Filiació URV: SI An efficient route to obtain allyl- and propargyl-containing diols from 10-undecen-1-ol, and their polymerization with isophorone diisocyanate to produce alkene- and alkyne-functionalized polyurethanes (PUs) is described. The bio-based PUs have been further modified by thiol-ene/yne coupling of thioglycerol into unsaturation to obtain a series of PUs with enhanced hydrophilicity. All the synthesized PUs were characterized by FTIR-ATR and NMR spectroscopy. As expected, the PUs were amorphous and DSC revealed glass transition temperatures in the range of 40 °C¿5 °C for the PUs before and after modification. The PUs exhibited highly tunable thermal and mechanical properties. The mechanical properties of these bio-based polymers (E modulus from 774 MPa to 6 MPa and at break from 45% to 401%) make the suitable materials for a large range of applications.

The single-electron transfer living radical polymerization (SET-LRP) of methyl acrylate initiated with bromoform (CHBr 3 ) and iodoform (CHI 3 ) and catalyzed by Cu(0)/Me 6 -TREN in DMSO at 25 °C provides a reliable method to prepare poly (methyl acrylate) (PMA) with active chain ends and controlled structure that can undergo subsequent functionalization to provide strategies for the synthesis of different block copolymers and other complex architectures. A detailed kinetic and structural analysis was used to assess the scope and the limitations of CHBr 3 and CHI 3 as initiators under SET-LRP conditions.

A new oxazolidine derivative was obtained from phenol, 2-amino-2-methylpropane-1,3-diol and paraformaldehyde. The reaction of this novel oxazolidine diol with phenylisocyanate lead to a urethane model compound which can be polymerized thermally by oxazolidine ring opening to give a Mannich bridge structure. Linear segmented polyurethanes were prepared by reaction of different ratios of oxazolidine diol and commercial polyethylenglycol (M w ∼ 400) with 4,4'-methylenbis (cyclohexylisocyanate) (HMDI, 90% isomers mixture). The polyurethanes were thermally characterized and crosslinked by oxazolidine ring opening to obtain materials which showed improved thermal stability.

Poly(methyl acrylate)s, poly(ethyl acrylate)s, and poly(butyl acrylate)s with α,ω-di(bromo) chain ends and Mn from 8500 to 35,000 were synthesized by single-electron-transfer living radical polymerization (SET-LRP). The analysis of their chain ends by a combination of 1H and 2D-NMR, GPC, MALDI-TOF MS, chain end functionalization, chain extension, and halogen exchange experiments demonstrated the synthesis of perfectly bifunctional polyacrylates by SET-LRP. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4684–4695, 2007

This study is concerned with the preparation and properties of a new class of bionanocomposites from renewable resources. Epoxidized linseed oil (ELO) and 3-glycidylpropylheptaisobutyl-T8-polyhedral oligomeric silsesquioxane (G-POSS) (2, 5, and 10 wt %) were cross-linked, and Fourier transform infrared spectroscopy (FTIR), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were employed to characterize the POSS-reinforced oil-based polymer networks. No POSS aggregates were observed for the 2 wt % G-POSS nanocomposite by SEM. POSS-rich particles with diameters of several nanometers were observed in the nanocomposites with 5 and 10 wt % G-POSS. Enhanced glass transition temperatures and storage moduli of the networks in the glassy state and rubber plateau were observed to be higher than those of the POSS-free oil based polymer network, due to the reinforcement effect of POSS cages.

A new phosphorous-containing fatty acid diepoxide was obtained from 10-undecenoyl chloride and 10-(2′,5′-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and crosslinked with 4,4′-diaminodiphenylmethane and bis(m-aminophenyl)methylphosphine oxide. The properties of the thermosetting materials were evaluated by differential scanning calorimetry, dynamic mechanical thermal analysis, thermogravimetric analysis, and limiting oxygen index (LOI). Thermal and thermooxidative degradation was studied by gas chromatography/mass spectrometry, FTIR, 31P magic angle spinning NMR spectroscopy, and scanning electron microscopy. LOI values indicate good flame-retardant properties that are related to the formation of a protective phosphorous-rich layer that slowed down the degradation and prevented it from being total. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5630–5644, 2006

Epoxy-novolac resins were synthesized by modifying a commercial novolac resin with epichlorohydrin. These epoxy-novolac resins were characterized and further modified with different contents of bis(benzo-1,3,2-dioxa-borolanyl)oxide or bis(4,4,5,5-tetramethyl-1,3,2-dioxa-borolanyl)oxide. The boron-containing epoxy-novolac resins were autocatalytically crosslinked or crosslinked with BF 3 MEA and their thermal stability and flame retardancy were determined by thermogravimetric analysis and limiting oxygen index (LOI) values. These LOI values for the bis(benzo-1,3,2-dioxa-borolanyl)oxide derivatives were higher than the boron-free novolac resins, which shows the benefit of the presence of boron. To test the role of boron in the enhancement of flammability, scanning electronic microscopy and energy-dispersive X-ray spectroscopy images were made.

Novel hybrid organic-inorganic materials were prepared from 10-undecenoyl triglyceride and methyl 3,4,5-tris(10-undecenoyloxy)benzoate via hydrosilylation. 1,4-Bis(dimethylsilyl)benzene, tetrakis(dimethylsilyloxy)silane, and 2,4,6,8-tetramethylcyclotetrasiloxane were used as crosslinkers. The hydrosilylation reaction was catalyzed by Karstedt's catalyst [Pt(0)-divinyltetramethyldisiloxane complex]. The networks were structurally characterized by Fourier transform infrared spectroscopy, 13 C NMR, and 29 Si magic-angle-spinning NMR. The thermal properties of these hybrids were studied with differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The obtained materials showed good transparency and promising properties for optical applications.

Oligomeric polyether polyols were obtained through the acid-catalyzed ring-opening polymerization of epoxidized methyl oleate and the subsequent partial reduction of ester groups to give primary alcohols. The oligomers were characterized with titration, spectroscopic techniques (Fourier transform infrared and nuclear magnetic resonance), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, size exclusion chromatography, and differential scanning calorimetry. Depending on the degree of reduction, polyols of different hydroxyl content values were obtained and were reacted with 4,4′-methylenebis(phenyl isocyanate) to yield polyurethanes. These materials, which were characterized by differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical thermal analysis, could behave as hard rubbers or rigid plastics. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 634–645, 2006

A family of supramolecular side-chain ionic polyurethanes (PUs) is synthesized by a simple method using polyurethanes with tertiary amines as pendant groups, and carboxylic acids. The resulting polyurethanes contain diethyl ammonium and carboxylate moieties that are bonded by a combination of ionic and hydrogen bonds. The self-assembling process is observed by Fourier-transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) and nuclear magnetic resonance (NMR) spectroscopy. The synthesized polyurethanes are characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Rheological, dielectric, and mechanical properties are investigated, and it is found that the tunability of the properties depends on the acid functionality and the chain length. Dynamic viscoelastic tests reveal a rapid and complete thermal reversibility, which opens the door to studying the recyclability of the samples.