Detection of residual acidic groups in several poly(<i>N</i>‐alkyl methacrylate)s using photophysical and photochemical probes

Christoff, Marcelo; Yamaki, Sahori B.; Oliveira, Mariana Gonçalves de; Atvars, Teresa Dib Zambon

doi:10.1002/app.20022

Cited by 5 publications

(15 citation statements)

References 31 publications

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“…6. The photoisomerization kinetics are always non-monoexponential, as observed for other guest-host systems [7,11,12,[22][23][24]. This behavior may be attributed to the existence of cavities with different free volumes where the guest can be located, and molecules in distinct environments isomerize with distinct rate constants.…”

Section: Resultsmentioning

confidence: 83%

“…The molecular weight and the polydispersity of the polymers were determined by gel permeation chromatography (Waters chromatograph, IR detector 410) using tetrahydrofuran (THF) as a mobile phase with flow rate of 1 mL/min and the column temperature was 40°C. The glass transition temperatures for these polymers are T g = 104°C and 95°C for PS and PMMA, respectively [11,12]. Films of PS and PMMA containing dissolved dyes were prepared by casting a toluene solution containing both the polymer and the dye in Petri dishes.…”

Section: Methodsmentioning

confidence: 99%

“…Photoisomerization kinetics studies were carried out by measuring the UV/VIS spectra in a spectrophotometer HP model 8452A during the sample irradiation with a highpressure 80 W Hg lamp. The light beam was filtered with a water cell sealed with quartz to remove infrared radiation [11,12]. An electromechanical shutter (Ealing 22-8411) was employed to irradiate the sample alternately and record the spectra.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Photoinduced birefringence in di-azo compounds in polystyrene and poly(methyl methacrylate) guest–host systems

Mendonça¹,

Misoguti²,

Andrade³

et al. 2007

Optical Materials

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Section: Resultsmentioning

confidence: 83%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Photoinduced birefringence in di-azo compounds in polystyrene and poly(methyl methacrylate) guest–host systems

Mendonça¹,

Misoguti²,

Andrade³

et al. 2007

Optical Materials

View full text Add to dashboard Cite

“…About 10 years ago in this Journal, Christoff et al . reported a few techniques to detect the occurrence of very small amounts of residual carboxylic acids present as contaminants in standard polymers such as poly(alkyl methacrylate)s and polystyrene.…”

Section: Introductionmentioning

confidence: 99%

“…reported a few techniques to detect the occurrence of very small amounts of residual carboxylic acids present as contaminants in standard polymers such as poly(alkyl methacrylate)s and polystyrene. They also shown that minute amounts of such acids in a polymer matrix had a very detrimental effect on the photophysical properties of various dyes, indicating that the acid content should be routinely monitored in polymers used for photonic applications to prevent reproducibility issues …”

Section: Introductionmentioning

confidence: 99%

A reinvestigation of a colorimetric method aimed at quantifying minute amounts of carboxylic acids present in polystyrene and poly(n‐alkyl methacrylate)s

Kerloc'h

Brissault

Penelle

et al. 2017

J of Applied Polymer Sci

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A reinvestigation of a method (Christoff, M.; Yamaki, S. B.; de Oliveira, M. G.; Atvars, T. D. Z. J. Appl. Polym. Sci. 2004, 92, 830-838) aimed at quantitatively determining trace amounts of residual carboxylic acid functional groups in polymethacrylates and polystyrene has been carried out. The original technique was based on the monitoring of an absorption band in the UV-visible region (610 nm) that appears after known amounts of polymer are added to a benzene solution containing the basic form of the Nile Blue A dye. It is shown here that the assumption upon which the methodology is based, that is, the occurrence of a 1:1 stoichiometric and complete proton transfer of the carboxylic acid to the dye, is invalid and yields greatly underestimated values for the COOH contents, possibly by 2-3 orders of magnitude. In addition, temperature strongly influences the equilibrium constant for the acidbase reaction. Lastly, preparation and storage of the analytical solution was found to be problematic, supporting earlier claims that hydrolysis of Nile Blue A base does occur when preparing the benzene solution and/or over storage, yielding Nile Red dye whose absorption in the visible part of the spectrum significantly overlaps. Based on the above results, further use of this technique, at least in its quantitative version, should be discouraged.

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Effects of temperature and CO2 pressure on the emission of N,N′-dialkylated perylene diimides in poly(alkyl methacrylate) films. Are guest-host alkyl group interactions important?

2016

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Static and dynamic fluorescence measurements have been made on four N, N −dialkylated perylene diimides in films of poly(alkyl methacrylate)s (PAMAs) with 5 different alkyl groups and in a 'model solvent', n-butyl acetate, over wide temperature ranges. The results indicate that the excited singlet states of the perylene guest molecules are controlled primarily by chain relaxations rather than hole free volumes in the polymer matrixes. The short singlet lifetimes of the perylene molecules require that the guest molecules respond primarily to the environments experienced by their ground states within the PAMA matrixes; each of the PAMAs offers slightly different locations in which the guest molecules can reside as a result of interactions between the N −alkyl substituents on the imide groups of the perylenes and the alkyl groups on the PAMA side chains. PAMAs with branched side chains were found to have a larger influence than PAMAs with linear side chains on the fluorescence properties of the guest molecules. The results are compared to those employing pyrenyl derivatives (with much longer excited singlet lifetimes) in the same PAMA films. The overall results indicate that the perylenes can be used as a complementary probe of local polymer chain dynamics, but they are less sensitive to their environments than are pyrenyl groups. However, they offer some distinct advantages: (1) a much wider range of N, N −disubstituted perylene diimides can be synthesized easily; (2) those substituents can be designed to allow a greater or lesser interaction with an anisotropic host matrix. Also, rapid conformational changes of a bis-perylene derivative appear to be restricted in the polymer matrixes. Those restrictions appear reduced when the polymer films are placed under high pressures of the plasticizing gas, CO 2 , but not when they are under equal pressures of a much less intervening gas, N 2 .

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Detection of residual acidic groups in several poly(N‐alkyl methacrylate)s using photophysical and photochemical probes

Cited by 5 publications

References 31 publications

Photoinduced birefringence in di-azo compounds in polystyrene and poly(methyl methacrylate) guest–host systems

Photoinduced birefringence in di-azo compounds in polystyrene and poly(methyl methacrylate) guest–host systems

A reinvestigation of a colorimetric method aimed at quantifying minute amounts of carboxylic acids present in polystyrene and poly(n‐alkyl methacrylate)s

Effects of temperature and CO2 pressure on the emission of N,N′-dialkylated perylene diimides in poly(alkyl methacrylate) films. Are guest-host alkyl group interactions important?

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