The present manuscript investigates the solution coordinative chain transfer polymerization (CCTP) of isoprene initiated by the ternary Ziegler‐Natta catalyst system composed by neodymium versatate (NdV3), diisobutylaluminum (DIBAH), and dimethyldichlorosilane. A kinetic mechanism is proposed and the kinetic parameters are estimated to allow the appropriate description of dynamic trajectories of average molecular weights and isoprene conversions obtained in solution CCTP polymerizations for the first time. A data reconciliation strategy is applied to evaluate the amount of DIBAH used as a chain transfer agent, as this very active compound can be consumed by undesired side reactions. Additionally, the impacts of key operation variables on the control of the average molecular weights and monomer conversion are evaluated to elucidate the living nature of the polymerization. As observed experimentally, the temperature effect on the course of the polymerization is not so pronounced as the effect of NdV3, isoprene, and DIBAH initial concentrations. The kinetic mechanism is described better and kinetic constants are estimated more precisely when the dynamic trajectories of average molecular weights are fitted during the whole batch. In this case, the proposed model is able to predict well the experimental trajectories of average molecular weights of the produced polymer and monomer conversion.

The monomer β‐myrcene, a renewable resource, was polymerized in cyclohexane using two different Ziegler‐Natta catalyst systems based on neodymium Nd(Oi‐Pr)3 and NdV3. The Nd(Oi‐Pr)3 was combined with [HNMe2Ph][B(C6F5)4] (or [CPh3][B(C6F5)4]) and Al(i‐Bu)3 (or Al(i‐Bu)2H). Next, the NdV3 was activated using Al(i‐Bu)3 and AlEt2Cl. Both catalyst systems exhibited high polymer yields near 100 % in the established reaction time, high polymer molecular masses, and broad molecular mass distributions. The catalyst systems gave an effective and stereospecific polymerization reaction of β‐myrcene providing high cis selectivity of 1,4‐polymyrcenes (> 92 %) with a glass transition temperature between −66 and −62 °C. The above‐mentioned features of resulting elastomers in conjunction with the polymer's molecular masses and molecular mass distributions proved to be sensitive to borane and alkylaluminum compounds molar ratios, [B]/[Nd] and [Al]/[Nd] using Nd(Oi‐Pr)3 and [Cl]/[Nd] and [Al]/[Nd] with NdV3.

Organoboron compounds of nonionic and ionic nature, tris(pentafluorophenyl)borane, and N,N-dimethylanilinium tetra(pentafluorophenyl)borate were evaluated to act in conjunction with MAO as activators on ethylene polymerization by using the catalyst Cp2ZrCl2. A decrease on the catalytic activity was observed in both cases in relation with a reference polyethylene which was synthesized in absence of any organoboron compound. An increase on the crystallinity degree and molecular weight, as well as an improvement in thermal and dynamic-mechanical properties, was observed in polyethylenes synthetized in presence of tris(pentafluorophenyl)borane. A low density polyethylene with improved thermal stability was obtained when N,N-dimethylanilinium tetra(pentafluorophenyl)borate was employed as activator.

Titanium dioxide doped silver (nTiO 2 /Ag) nanoparticles were surface-modified by microwave-assisted polymerization of 2-bis-(hydroxyethyl) terephthalate (BHET). The modified and unmodified nanoparticles were analyzed by FTIR, XRD, TGA, and TEM. A thin layer of grafted PET on the surface of the nanoparticles was observed and quantified by TGA giving a value of 40 wt-%. XRD and electron diffraction analyses showed traces of AgO 2 after the modification. The bactericide activity of modified and unmodified nanoparticles was evaluated; the presence of the thin layer of grafted-PET on the nTiO 2 /Ag did not change significantly the bactericide activity, showing an excellent performance similar to unmodified nanoparticles.

Composites based on low-density polyethylene (LDPE) were prepared withAgavefiber powder (AFP) that was coated by plasma polymerization process using ethylene gas. Treated and pristine AFP were analyzed by infrared spectroscopy, scanning electron microscopy, and contact water angle for the assessment of surface properties. The polymer composites were prepared by melt mixing using 0, 5, 10, and 20 wt% of AFP and their mechanical and thermal properties were measured. Dispersion evaluation in water confirmed that the AFP treated changed from hydrophilic to hydrophobic behavior and it was also corroborated with water contact angle tests. The addition of treated and untreated AFP (200 mesh) at 20 wt% promotes an increase of Young’s modulus of the composites of up to 60% and 32%, respectively, in relation to the neat matrix. Also, an increase of crystallinity of LDPE was observed by the addition of treated and untreated AFP; however no significant effect on the crystallization temperature was observed in LDPE containing AFP.

Triisobutylaluminum (TIBA), triethylaluminum (TEA), di-isobutylaluminum hydride (DIBAH) and methylaluminoxane (MAO) were evaluated as activators of neodymium chloride tripentanolate catalyst in order to investigate their influence over the catalytic activi-ty, macro- and microstructure, and thermal properties of of resulting polybutadienes. The higher catalytic activities were achieved by TEA and TIBA as co-catalysts, whereas TIBA and DIBAH led to the poly-mers with highest cis-1,4 structure content with 98.4 and 97.3% re-spectively. The catalytic activity was remarkably poor with MAO as co-catalyst, as well as low stereocontrol. Number average molecular weight values were observed in the range of 260 to 720 kg/mol.

Polymer flooding depicts an interesting strategy to improve the enhanced oil recovery (EOR). This work aims with the synthesis of ionic thermo‐responsive copolymers able to be used as rheological modifiers for EOR under harsh conditions (250,000 ppm of NaCl at 150°C). Copolymers composed of different molar ratio of acrylamide, N‐isopropylacrylamide and 2‐acrylamide‐2‐methyl‐1‐propanesulfonic acid were prepared in aqueous media via free radical polymerization at 50°C using 4,4′‐azobis(‐4″‐cyanopentanoic) acid (ACPA) as initiator. Nuclear magnetic resonance analyses demonstrated the structure and molar composition of synthesized copolymers. Rheological measurements performed at different concentration from 1 to 8 wt% demonstrated an increase in the viscosity from 2000 to 600,000 mPa.s. Aqueous mixtures of polymer at 5 wt% and NaCl at different concentration (5, 10, 15, 20, and 25 wt%) was analyzed. Copolymer ([PAM]/[PNIPAM] = 50/50) displayed a phase separation at 15 wt% of NaCl. Solutions of polymer at 5 and 25 wt% of NaCl were heated at 150°C for 72 h. Results revealed both thermal stability and saline tolerance of copolymers [PAM]/[PNIPAM]/[PAMPS‐Na] = 25/25/50, 35/35/30, and 50/0/50 under harsh conditions with the absence of phase separation of the brine polymer solutions.

In the course of our systematic study of structure/reactivity relationships for heterocycles, the reaction of recyclization of oxazolo[3,2-a]pyridinium salts with annelated cycloalkane fragments of different size revealed some unexpected peculiarities. All obtained compounds were studied by single crystal (1a-d, 3c, 4b,c) or powder (4d) diffraction. The previous results are reported in [1]. As discovered earlier, compounds 1b,d easily gave corresponding indolizines 4b,d. In the case of compound 1c the reaction suddenly stopped at the non-predicted intermediate 3c (with ClO 4 -anion). It can be explained by the less distortion of 7-membered ring connected to a non-planar bicycle than in 4c. Dehydratation of 3c led to 4c. Compound 1a was also attacked by piperidine, but only resin was formed. In this case, the unstable intermediate 2a is unable to react further because compounds 3a and 4a have high angle distortions as the AM1 molecular model shows.[1] Acta Cryst., 2004, E60, o1096-o1097, o1301-o1302, o2313-o2314. Molecular CT-complexes obtained by reacting acceptors such as diiodine with S-donor molecules, have been extensively studied mainly due to their intrinsic structural, spectroscopic, chemical and physical properties and, recently, to their applicability as conducting materials or as oxidation reagents towards transition metals. With the view to synthesize complexing-oxidizing agents capable to dissolve noble-metals (NMs) in mild conditions, we have chosen exa-and epta-atomic cyclic dithioxamides as bidentate S,S-donors. By reacting the N,N'-dialkyl-perhydrodiazepine-2,3-dithione (R 2 dazdt, R=Me (a), Et (b)) class of ligands with I 2 the expected 1:2 CT-complexes, R 2 dazdt 2I 2 (1), have been obtained as proved by structural and spectroscopic characterization. Keywords[1] Instead, by using the N,N'-dialkylpiperazine-2,3-dithione (R 2 pipdt, R=Me, Et, Pr i (c)) class, which shows an exa-atomic ring in spite of the hepta-atomic one in R 2 dazdt, the unexpected triiodide salt of the protonated donors, [R 2 pipdtH]I 3 (2), have been isolated. The different nature and structure of the two class of reagents is reflected on a different reactivity towards NMs: while class 1 adducts are capable to oxidize Pd and Au metal but are inactive towards Pt, class 2 reagents are capable to dissolve Pt metal too. Further studies are in progress in order to clarify the different behaviour of the two class of ligands and the source of H + in the reaction.[1] Serpe A., et al., Chem. Commun., 2005, 1040 Nickel(II) compounds containing sterically demanding -diimine ligands, and related chelates, have been found to be attractive catalysts for the production of polyolefins.[1] Dendrimers can be used as welldefined supports for active centers in homogeneous phase, which catalytic applications are being widely studied, [2] including those in polymerization processes. [3] In this work, a series of carbosilane dendritic compounds Gn-ONNMe m NiBr 2 (n = 0, 1, 2, 3; m = 0, 2, 3), from monometallic to metallodendritic structures conta...