Over the past years, polymer-supported reagents have been extensively studied and used in various applications. One class of such reagents is called "scavengers," which can be used to easily eliminate compounds in a solution. The present work describes the production of a resin that can be used for scavenging ketones and aldehydes using low-cost reagents and simple reaction steps, named here Amb15-Iso. This resin is obtained by reacting a low-cost commercial sulfonyl resin, Amberlyst-15, with isoniazid, a drug used for the treatment of tuberculosis. Acetone and isobutyraldehyde were used as carbonyl compound models. The reactions were monitored in-line by ATR-FTIR and results showed that the polarity of the solvent influences the kinetics of the production of the resin and water proved to be the fastest solvent. For the scavenging of acetone and isobutyraldehyde, two factors showed to have an impact in the amount of compounds captured: the polarity of the solvent and the solubility of water in the solvent. The capacity of scavenging acetone in water varied from 0.11 to 0.28 mmol per gram of resin, depending on the initial acetone concentration. The equilibrium of this reaction was modeled and the equilibrium constant was calculated to be 0.63 6 0.07 L mol 21 . The resin was also recycled and tested in a second round of scavenging and results showed that there was not much difference between the new resin and the recycled one, proving that the Amberlyst-15 could be reused for a second cycle of scavenging. V C 2015 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 2015, 132, 42291.
Magnetized styrene‐divinylbenzene resins can be obtained by inserting superparamagnetic nanoparticles of maghemite (γ‐Fe2O3) in the polymeric matrix. The incorporation of this nanoparticulate material can be influenced by several factors. The objective of this work was to evaluate the influence of these variables through an experimental design, where three factors were evaluated: cross‐linking degree, initiator content and porogenic agent, at two levels. Subsequently, to evaluate the properties of the synthesized magnetized resins, magnetization curves were plotted using a vibrating sample magnetometer, thermal stability of the magnetized copolymer was determined by thermogravimetric analysis and the morphology was observed by scanning electron microscopy. The highest initiator content produced the greatest synthesis yield, and the presence of toluene had a positive effect on saturation magnetization, indicating that incorporation of maghemite in the polymer matrix and thermal degradation were influenced by higher divinylbenzene content.
Nanopartículas de maghemita (γ-Fe2O3) vem sendo sintetizadas pela técnica de coprecipitação por hidrólise alcalina para magnetizar matrizes poliméricas. Neste trabalho foram sintetizadas nanopartículas de ferro caracterizadas por diferentes técnicas mostrando pelo seu tamanho de partícula que esse material apresentou propriedades superparamagnéticas.
Resinas de estireno-divinilbenzeno magnetizadas são copolímeros magnéticos esféricos constituídos de uma matriz polimérica contendo dois monômeros, e um material com propriedades magnéticas que pode se arranjar no interior do polímero ou na sua superfície. Há um grande desafio envolvido na distribuição uniforme do material magnético em matrizes poliméricas de estirenodivinilbenzeno. Estudos mostram que a quantidade de material magnético incorporado na matriz polimérica ao termino da polimerização é inferior à quantidade adicionada no início da reação. Este fato pode ser atribuído às características hidrofílicas das nanopartículas. Resinas de estirenodivinilbenzeno vêm sendo sintetizadas por polimerização em suspensão em meio aquoso, na qual uma fase orgânica é dispersa no meio contínuo. A interação entre a água e as partículas magnéticas pode ser um dos motivos que dificultam a incorporação do material magnético na matriz polimérica, resultando na perda do material magnético para o meio contínuo. O uso da glicerina ou mistura de água/glicerina, como meio contínuo, foi proposto neste trabalho a fim de avaliar se a substituição de água por um solvente menos polar e mais viscoso teria influência na incorporação das partículas magnéticas nessas matrizes de estireno-divinilbenzeno. A morfologia das esferas foi avaliada por microscopia eletrônica de varredura. As resinas foram caracterizadas por espectroscopia na região do infravermelho, analise termogravimétrica, força magnética e difração de raios X. O aumento do teor de glicerina no meio dispersante ocasionou um aumento na força magnética das resinas, porém alterou a morfologia das mesmas.
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