Phenyleneimine oligomers 4,4'-(((1E,1'E)-(((1E,1'E)-(1,4-phenylenebis-(azanylylidene))bis(methanylylidene))bis(2,5-bis(octyloxy)-1,4-phenylene))bis(methanylyl-idene))-bis(azanylylidene))dianiline (OIC1MS) and 7,7'-(((1E,1'E)-(((1E,1'E)-((9H-fluorene-2,7-diyl)bis(azanylylidene))bis(methanylylidene))bis(2,5-bis(octyloxy)-1,4-phenylene))bis- (methanylylidene))bis(azanylylidene))bis(9H-fluoren-2-amine) (OIC2MS) were prepared by means of conventional and mechanochemical synthesis and characterized by FT-IR, 1H- and 13C-NMR techniques. The optical properties of the compounds were studied in solution by using UV-visible spectroscopy, and the optical effects were analyzed as a function of solvent. The results show that OIC2MS exhibits interesting photochromic properties. Furthermore, the structural and electronic properties of the compounds were analyzed by TD-DFT. It was found that the mechanosynthesis is an efficient method for the synthesis of both tetraimines.

A new anthracene-containing diamine, (E)-9-~-(2,4-diaminophenyI)vinyl]anthracene, was prepared and used for the synthesis of a series of polyamides and polyimides by low temperature solution polycondensation. The polymers were highly amorphous, soluble in aprotic solvents and gave films with good optical quality on spin-casting. The polymers showed 10% weight loss at a temperature of 415-460°C under nitrogen. The poymers exhibited an intense luminescence in the region of 450-500 nm due the emission from the excited state of the diamine moiety. It was shown that charge-transfer (CT) interactions in polyimides were negligibly small in both the ground and the excited state, probably due to the bulky diamine fragment together with the rigid polymer backbone.

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Two novel bifunctional monomers obtained from PET waste glycolisis are reported. Bis(2-(acryloyloxy)ethyl) terephthalate and bis(2-(((allyloxy)carbonyl)oxy)ethyl) terephthalate (BACET) monomers were obtained from bis(hydroxyethyl) terephthalate derived from PET waste and acryloyl chloride and allyl chloroformate, respectively. The monomers were characterized by FTIR and 1 H-NMR spectroscopies. They were evaluated as crossslinking agents for acrylic acid (AA) and methacrylic (MA) acids using thermally initiated polymerization. The obtained copolymers showed higher thermal stability than the acrylic homopolymers. They were also tested for dental formulations as Bis-GMA substitutes in heat curing resin composites. In spite of its lower reactivity, only BACET was able to substitute Bis-GMA, due to its high solubility in the TEGDMA comonomer. Resin formulations containing nanosized silica and the mixture Bis-GMA/TEGDMA or BACET/TEGDMA were prepared in order to compare physical and chemical properties. Water sorption, solubility, and flexural strength were found statistically similar for both formulations. However, flexural modulus was lower and double bond conversion was higher for the BACET resin, which could make it appropriate for its potential use in dental resin composites.

The purpose of this study is to report the formulation of photopolymerizable composites resins with hydrophobic behavior using a new urethane monomer (ETODC) as additive. The ETODC monomer was used together with Bis-GMA and TEGDMA to formulate a new organic matrix system. Mechanical and hydrophobic behavior were studied, also volumetric shrinkage, viscosity, polymerization kinetics and cytotoxicity were analyzed. Results were compared with a control resin prepared with Bis-GMA and TEGDMA. The results show that mechanical properties and volumetric shrinkage did not present statistical differences between the studied groups. When compared with the control material, the experimental resin formulated with the ETODC monomer showed higher hydrophobic behavior and higher values of degree of conversion and polymerization rate.