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An experiment for the calculation of the degree of double bond conversion, after a polymerization reaction, of photopolymerizable liquid monomers using FTIR-ATR spectroscopy is reported. The experiment was successfully conducted with undergraduate students in materials engineering during the Fundamentals of Polymeric Material course. Students synthesized a Bis-GMA and TEGDMA copolymer through radical chain polymerization using visible light as the energy source (photopolymerization). Through the quantitative analysis of two absorption bands in the FTIR spectra of the monomer and the polymer, the νCC of the alkene group at 1638 cm −1 and the νCC of the aromatic ring at 1610 cm −1 , students calculated the degree of double bond conversion after the polymerization reaction. Students acquired competencies in the synthesis and qualitative and quantitative characterization of polymeric materials through FTIR spectroscopy.

Two new bisallylic monomers [allyl p‐allyl carbonate benzoate (ApACBz) and 1,4‐phenylenbis(methylene)diallyl carbonate (1,4‐FMDAC)] and one bisacrylic monomer [1,4‐bis(acryloyloxymethyl)benzene (1,4‐BAMB)] were synthesized and used as crosslinking agents of methyl methacrylate (MMA) at different mass ratios (10, 20, 40, and 50%). All of the obtained copolymers showed improved thermal stability in comparison with that of the MMA homopolymer. Also, ApACBz and 1,4‐FMDAC were used as bisphenol A glycidyl methacrylate (Bis‐GMA) eluents to prepare dental resin composites. When compared to the control, the Bis‐GMA–new eluent composites had a higher double‐bond conversion, a higher solubility (p < 0.05) and a lower flexural strength (p < 0.05), whereas the elastic modulus and water sorption values were not statistically different (p > 0.05). The 1,4‐FMDAC and ApACBz monomers are promising eluents of Bis‐GMA for the preparation of dental composites with high degrees of conversion. In addition, the ApACBz, 1,4‐FMDAC, and 1,4‐BAMB monomers are potentially useful crosslinking agents when polymer networks of poly(methyl methacrylate) with a high thermal stability are desired. The application‐oriented tests of the monomers in dental composite formulations showed a sufficient storage stability, high photocuring activity, excellent crosslinking of MMA, and good thermal and mechanical properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42920.

BACKGROUND Adsorption is one of the most commonly used methods for the removal of textile dyes because of its low cost and ease of operation. Nowadays, unconventional materials capable of specific interactions such as polyelectrolytes are being proposed to be used as adsorbents. This work presents the results of the application of chemically modified polyelectrolytes derived from chitosan containing amino and sulfonate groups in the adsorption of four textile dyes, as well as the treatment of wastewater from the textile industry. RESULTS By optimizing the conditions of static adsorption, approximately 90% of the cationic dyes present in an aqueous solution with an initial concentration of 300 mg dm−3 and a basic pH of around 11.5 were removed. Anionic dyes almost reach 100% adsorption on the polyampholytes. The point of zero charge (pHpzc) was determined, and it was found that both polyampholytes exhibited a basic character on their surface (pHpzc > 8.7). The adsorption isotherms for the cationic and anionic dyes fit Langmuir's model, and the values for RL indicated that the process of adsorption for cationic and anionic dyes is energetically favorable on both polyampholytes. CONCLUSIONS The chemical modification introducing sulfonate groups on chitosan does not affect its natural ability to adsorb anionic dyes, but it also allows it to adsorb high concentrations of cationic dyes. This way, semisynthetic polyelectrolytes were capable of improving the quality of wastewaters treated by adsorption by reducing their pH, making it less alkaline, and decreasing the color, contents of suspended solids, and COD. © 2017 Society of Chemical Industry

Two novel polyelectrolytes were obtained by chemical modification of poly(4-acryloyloxybenzaldehyde) using o-and p-aminophenylsulfonic acid, the characterization shows a chemical modification of 24.38 and 63.33%, respectively. The study shows that the polyelectrolyte with sulfonic acid in para position reduces metal ions more rapidly than polyelectrolyte in ortho position. The obtained nanoparticles of Au and Ag were characterized by ultraviolet-visible absorption spectroscopy (UV-vis) and transmission electron microscopy. The results showed that these ionic polymers are not only capable of reducing gold and silver ions, but also can stabilize the nanoparticles in the colloidal solutions. With these polymers, the process of metallic ions reduction is very slow and they lead to the production of Au and Ag nanoparticles with quasi-spherical shapes which are stable in colloidal solutions for several months. The advantage of the method used here is that the reduction can be realized in water at room temperature.