The ring size of cyclic amines influences the yield, Mw and PDI values of polynorbonene obtained via ROMP using [RuCl2(PPh3)2(amine)x] as the starting complex.

In this paper, a new synthesis method was proposed to obtain anatase titanium oxide (TiO 2) nanocrystals anchored into SBA-15 molecular sieve, as a matrix assigned by the in-situ anchoring (ISA) method. Pure SBA-15 and modified with TiO 2 nanocrystals at different Si/Ti molar ratios (R = 75, 50, and 25) were structurally characterized by X-ray diffraction (XRD), Micro-Raman and Fourier Transform infrared (FTIR) spectroscopies. Specific surface area, pore volume and average pore diameter were estimated using both Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods, respectively. Morphological aspects of these samples were observed by means of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Optical properties were investigated by ultravioletvisible (UV-vis) diffuse reflectance spectroscopy. XRD patterns, Micro-Raman and FT-IR spectra indicate the TiO 2 nanocrystals crystallized in a tetragonal structure anchored into the SBA-15 mesopores. BET and BJH methods prove a large amount of TiO 2 nanocrystals were anchored inside of SBA-15 mesopores due to increase in surface area and average pore size of SBA-15 matrix. FE-SEM and TEM images showed the pure SBA-15 has an elongated hexagon-shaped microstructure, and an average size of 7.34 nm for 2D hexagonal mesopores. Moreover, ISA method was able to avoid blocking of mesopores, in addition promotes a significant increasing the impregnation rate of anatase TiO 2 nanocrystals in SBA-15 matrix. A growth mechanism was proposed in order to explain the stages involved in the formation of TiO 2-SBA mesoporous. UV-vis spectra revealed a dependence of the optical band gap energy (E gap) with the decreasing of Si/Ti molar ratios.

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The obtained plant oil-based copolymers were insoluble in water and in various slightly polar solvents, and swelling up to 800% in chloroform.

Copolymers from norbornene (NBE) with norbornadiene (NBD) were synthesized via ring opening metathesis copolymerization varying the mole fractions of the comonomers (0.8 : 0.2; 0.6 : 0.4; 0.4 : 0.6; 0.2 : 0.8) for a total monomer quantity of 5000 equivalents/[Ru]. The batch reactions were performed with [RuCl2(PPh3)2(amine)] complex types as precatalysts, where amine is perhydroazepine (1) or piperidine (2), in CHCl3 (2 mL) in the presence of ethyl diazoacetate (5 μL) for different intervals of times (5, 30, 60, and 120 min) at 40°C. The copolymers were characterized by 13C NMR. Quantitative yields of isolated materials were obtained from solutions with NBD : NBE 0.8 : 0.2 mole fraction in the presence of 1, decreasing to 70% for NBD : NBE 0.2 : 0.8 solutions. Concerning 2, the yields were 70% at most. Polymeric materials obtained with 1 were less soluble in CHCl3 than those synthesized with 2. The dependence of the reaction yields and occurrence of crosslinking on the starting NBE : NBD proportion related to reactivity of the complexes 1 and 2 were discussed. A few differences in the amines such as ancillary ligands were sufficient to change the reactivity of the {RuCl2(PPh3)} moiety complex to provide copolymers with different compositions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Ring-opening metathesis polymerization (ROMP) of norbornadiene (NBD) with [RuCl 2 (PPh 3) 2 (pyrrolidine)] as the starting complex was evaluated as a function of reaction time, solvent volume, and atmosphere type at 25°C. Quantitative yields of polyNBD were obtained either under inert argon atmosphere or in air, with 2 mL of CHCl 3 , for 30 min. Copolymerization of NBD with norbornene (NBE) resulted in 100-70% yield under argon, depending on the NBE/NBD molar ratio, and in 70% yield in air, with 2 mL, for 120 min. TGA, DSC, and DMA measurements and swelling tests supported the occurrence of cross-linking in homopolyNBD and in the copolymers isolated from polymers. SEM micrographs showed porous polymeric NBD materials with pores that decreased in size when increasing the amount of NBD in the starting reaction composition. Results from amine parent complexes when the amine was piperidine or perhydroazepine are also discussed, with high cross-linking degree from reaction with the pyrrolidine complex.

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Recebido em 28/6/11; aceito em 27/10/11; publicado na web em 4/1/12 ROMP AS A VERSATILE METHOD FOR THE OBTENTION OF DIFFERENTIATED POLYMERIC MATERIALS. Ring Opening Metathesis Polymerization (ROMP) of cyclic olefins is a powerful transition metal-catalyzed reaction for syntheses of polymers and copolymers. The key feature of this reaction is the [2+2]-cycloaddition mechanism, with retention of the olefinic unsaturation in the polymer chain and occurrence of living polymerization. With the development of metal-carbene type catalysts for this process, many addressed polymeric materials have been successfully prepared to be employed in several fields of the science and technology. This review summarizes recent examples of syntheses of polymers with amphiphilic features such as block, graft, brush or star copolymers; as well syntheses of biomaterials, dendronized architectures, photoactive polymers, cross-linked or self-healing materials, and polymers from renewed supplies.