A polarised μ-FTIR study on a model system for nylon 6 6: implications for the nylon Brill structure

Cooper, Sharon J.; Coogan, Mike; Everall, Neil; Priestnall, Ian

doi:10.1016/s0032-3861(01)00566-3

Cited by 89 publications

(108 citation statements)

References 35 publications

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“…4), in particular using the band at ~3450 cm -1 that strongly weakens after drying. Two other well-known characteristics in the case of compounds containing amide groups are also visible, the splitting of the N-D mode (which does not relate to the existence of two N-D bonds) and a strong N-H combination towards 3075 cm -1 [8]. The shape of the IR bands being less well defined than in Raman diffusion, the measurement of the [crystalline/amorphous] proportion is coarser.…”

Section: Resultsmentioning

confidence: 98%

Raman and IR micro-analysis of high performance polymer fibres tested in traction and compression

Colomban

Gouadec

2009

Composites Science and Technology

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Section: Resultsmentioning

confidence: 98%

Raman and IR micro-analysis of high performance polymer fibres tested in traction and compression

Colomban

Gouadec

2009

Composites Science and Technology

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“…FTIR is a powerful technique to obtain information about hydrogen bond interactions and the arrangement of methylene sequences in aliphatic polyamides [45,46]. Thus, the wavenumber of the Amide A band (NH stretching mode) is directly related to the strength of intermolecular hydrogen bonds.…”

Section: Ftir Data On Heating and Cooling Processes: Hydrogen Bonds Amentioning

confidence: 99%

Reversible changes induced by temperature in the spherulitic birefringence of nylon 6 9

Murase

Casas

Martínez

et al. 2015

Polymer

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Spherulitic morphologies of nylon 6 9 as an example of an even-odd nylon were studied by optical microscopy. A well-defined dependence on crystallization temperature was found. In particular, positively birefringent spherulites were characteristic for temperatures higher than 232 ºC, low birefringence spherulites developed between 232 and 225 ºC, positive ringed spherulites were found between 225 and 220 ºC, and finally negative fibrillar spherulites were formed at temperatures lower than 220 ºC. These optical properties were clearly different from those observed with even-even nylons (e.g., negative and positive birefringence for high and low temperatures, respectively), and may derive from the peculiar crystalline structures determined for even-odd nylons.Furthermore, low birefringence spherulites were characterized by a flat-on lamellar disposition and reversibility of the birefringence sign in the 80-120 ºC temperature interval (positive and negative values at high and low temperatures, respectively).Real time WAXD profiles taken during heating and cooling processes demonstrated that different crystalline structures (named I, II and III) developed depending on the temperature and crystallization procedure of samples (e.g., from solution or from the melt state). Crystalline structures were characterized by the formation of hydrogen bonds along two crystalline directions in all cases, a peculiar arrangement that may account for the development of positive and negative spherulites in a more simple way than formulated for conventional polyamides having a single hydrogen bonding direction. DSC and FTIR data also showed a complex structural behavior with structural transitions in the 80-120 ºC range, a region that corresponds to birefringence sign reversibility.

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“…21,23 Esse fato pode ser confirmado pela espectroscopia vibracional na região do infravermelho, no qual as bandas em 934 cm -1 atribuídas ao estiramento C-CO e em 1202 cm -1 , a banda característica da interação de amida III com o esqueleto hidrocarboneto, indicam a existência das fases cristalinas. 23,24 Os DRXs das membranas modificadas após a adição do complexo de európio com 1,10-fenantrolina [Eu(phen) 2 . (H 2 O) 2 ]Cl 3 apresentaram as mesmas razões entre os picos das formas α e g, indicando que o complexo também não influenciou na ligações de hidrogênio das cadeias.…”

Section: Difração De Raios X (Drx)unclassified

Modificação de membrana de poliamida via sol-gel e incorporação de composto de európio (III) luminescente

et al. 2016

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. Over the last decades, the combination of different technologies to search for systems with new properties and features has brought various segments of biological and earth sciences together. Additive manufacturing, known as rapid prototyping, combined with the sol-gel methodology enables the production of novel systems with applications in many scientific fields. In this work, flexible polyamide membranes were obtained by additive manufacturing, functionalized by the sol-gel methodology, and incorporated with the coordination compound between Eu(III) and 1,10-phenanthroline. The presence of vibrations at 1100 cm -1 in the FTIR spectrum of the material, which is a band typical of the Si-O-Si group in the alkoxide employed during the process, confirmed the polyamide membrane functionalization. The thermogravimetric curve showed that a residue remained after heating at 700 o C, which was attributed to SiO 2 . The membrane was highly luminescent, which confirmed incorporation of the Eu 3+ compound into the material and pointed to the possible application of this system as a topical medication for the treatment of skin diseases.Keywords: sol-gel; photodynamic therapy; luminescence; europium III compounds. INTRODUÇÃOA terapia fotodinâmica (TFD) é uma técnica aplicada no tratamento de câncer de pele e que utiliza a luz (radiação eletromagnética) para tal. Resumidamente, a área tratada é exposta a radiação monocromática, região do visível (600 à 800 nm), após a administração de um fotossensibilizador que absorve a radiação e em seguida transfere a energia ao oxigênio molecular, gerando espécies reativas de oxigênio e, consequentemente, a oxidação dos lipídios, aminoácidos e proteínas, o que resulta na destruição do tumor.1,2 A técnica TFD utiliza emulsões, microemulsões, nanoemulsões, que são aplicadas diretamente sobre a pele e, após um determinado tempo, são absorvidas pelas células tumorais. A literatura tem relatado a utilização de vários sistemas que contém nanopartículas e fotossensibilizados. [3][4][5] Os elementos lantanídeos apresentam, como uma de suas principais carcterísticas, a propriedade fotoluminescentes, amplamente aplicadas na geração de radiação eletromagnética nas regiões do visível e infravermelho. As transições interconfiguracionais f -f são as responsáveis por essas propriedades.6-8 Os íons lantanídeos podem sofrer excitação nas regiões do ultravioleta, visível e infravermelho, o que resulta em linhas de emissão monocromáticas na região do visível e do infravermelho. Por exemplo, o íon Eu 3+ apresenta intensa emissão na região vermelha do espectro eletromagnético, aproximadamente em 620 nm, quando excitado no ultravioleta (394 nm) e visível (460 nm).9-11 A combinação de elementos adequados também pode apresentar alta eficiência de emissão na região do visível quando se utiliza a radiação infravermelha, chamado de conversão ascendente, como por exemplo o par Yb 3+ -Tm 3+. 12 Portanto, os íons lantanídeos apresentam características para serem utilizados como emissores de radiação na região visíve...

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A polarised μ-FTIR study on a model system for nylon 6 6: implications for the nylon Brill structure

Cited by 89 publications

References 35 publications

Raman and IR micro-analysis of high performance polymer fibres tested in traction and compression

Raman and IR micro-analysis of high performance polymer fibres tested in traction and compression

Reversible changes induced by temperature in the spherulitic birefringence of nylon 6 9

Modificação de membrana de poliamida via sol-gel e incorporação de composto de európio (III) luminescente

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