Inorganic-organic hybrids based on poly (ε-Caprolactone) and silica oxide and characterization by relaxometry applying low-field NMR

Monteiro, Mariana de Souza de Bustamante Sato; Neto, Roberto P.C.; Santos, Izabel Cristina Souza; Silva, Emerson Oliveira da; Tavares, Maria Inês Bruno

doi:10.1590/s1516-14392012005000121

Cited by 38 publications

(21 citation statements)

References 35 publications

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“…The Thermogravimetric analysis (TGA) was carried out on TA instruments Q500 (USA) apparatus from 25˚C to 500˚C under nitrogen flow (50 mL/min) at 10 ˚C/min heating rates [2] [16].…”

Section: Thermal Analysismentioning

confidence: 99%

“…A wide range of nanoparticles such as: clays, carbon nanotubes, graphites, polyhedral oligomeric silsesquioxane and metal oxides are currently available and they are used to prepare these systems [1]. Moreover, the uniform dispersion of these nanofillers produces a large interfacial region between the nanofiller and polymer, due to its high surface area, leading to peculiar characteristics [2].…”

Section: Introductionmentioning

confidence: 99%

“…Normally, when spherical nanoparticles such as: titanium dioxide and silica are well dispersed and distributed in the polymer matrix, the proton-spin lattice relaxation times increases because of the rigid behavior of these particles in the polymer matrix [2] [8].…”

Section: Introductionmentioning

confidence: 99%

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The Development and Characterization of Polycaprolactone and Titanium Dioxide Hybrids

Monteiro¹,

Tavares²

2018

ANP

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Organic/Inorganic hybrid materials have been attracting much attention since they combine the advantages of inorganic materials with the properties of organic polymers. Titanium dioxide nanoparticles (TiO 2 ) present good thermal stability, accessibility and catalytic properties. Polycaprolactone (PCL) is a biocompatible and bioresorbable material, which is being examined as biodegradable packaging materials, controlled drug release carriers and other medical applications. Hybrids based on PCL containing different amounts of titanium dioxide nanoparticles, ranging from 0.05% to 0.35% w/w, were prepared using the solution cast method. These systems were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), low-field nuclear magnetic resonance (NMR), thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The FTIR analysis confirmed that there was an interaction between the PCL chains and the TiO 2 nanoparticles. The XRD and DSC analysis showed that the PCL crystallization was affected by TiO 2 incorporation, modifying its semi-crystalline structure to a less ordered structure. When TiO 2 nanoparticles were added the values of T 1 H and T 1 ρH increased for all hybrids, therefore, their addition produced a new material with less molecular mobility. In the TG analysis, it was observed that the introduction of TiO 2 nanoparticles decreased the thermal resistance of PCL. In DSC analysis, the PCL/TiO 2 hybrids presented a reduction in the crystallization temperature and degree of crystallinity, except for PCL hybrids containing 0.15% w/w of TiO 2 nanoparticles.

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“…The Thermogravimetric analysis (TGA) was carried out on TA instruments Q500 (USA) apparatus from 25˚C to 500˚C under nitrogen flow (50 mL/min) at 10 ˚C/min heating rates [2] [16].…”

Section: Thermal Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Development and Characterization of Polycaprolactone and Titanium Dioxide Hybrids

Monteiro¹,

Tavares²

2018

ANP

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“…Tempos de relaxação dos núcleos de hidrogênio do amido, da viscogel B8 e amido/Viscogel B8 determinado por RMN-BC. confirma o fato de que a inserção de nanopartículas causa um aumento na desordem cadeia, gerando diferentes formas de organização molecular [26][27][28]37] .…”

Section: Rmn-bcunclassified

Desenvolvimento de Nanocompósitos à base de Amido de Batata

Brito¹,

Tavares²

2013

Polímeros

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Resumo: Nanocompósitos de amido de batata foram preparados pelo método de intercalação por solução, com a adição de argilas montmorilonita: organicamente modificada (Viscogel B8) e não modificada argila sódica (NT25) e de sílicas: modificada (R972) e não modificada (A200). Os nanocompósitos foram caracterizados pelas técnicas convencionais de difratometria de raios X e análise termogravimétrica. Foram caracterizados também por uma técnica denominada como não convencional, a ressonância magnética nuclear (RMN) de baixo campo, que é alternativa e efetiva na caracterização de nanocompósitos. Com ela, pode-se investigar a dispersão das nanocargas pelo grau de intercalação e/ou esfoliação, além de verificar a distribuição e modificações da mobilidade molecular da matriz polimérica. Os materiais nanoestruturados obtidos com as argilas apresentaram boa dispersão e formação de nanomateriais mistos, com diferentes graus de intercalação e esfoliação. Ao adicionar as sílicas na matriz de amido pode-se observar uma diminuição da mobilidade do material, este efeito foi observado para ambas às sílicas utilizadas. Utilizando a técnica de TGA verificou-se um ligeiro aumento na estabilidade térmica do material produzido em relação ao amido. Palavras-chave: Amido, nanocompósitos, RMN de baixo campo. Development of Nanocomposites Based on Potato StarchAbstract: Nanocomposites of potato starch were prepared by the solution intercalation method with the addition of organically modified montmorillonite clay (Viscogel B and unmodified sodic clay (NT25) as well as modified and unmodified silica (R972 and A200, respectively), using water as the solvent. The nanocomposites were characterized by conventional techniques of X-ray diffraction and thermogravimetric analysis. They were also characterized using the non-conventional low-field nuclear magnetic resonance, which is an effective alternative technique for characterizing nanocompósitos. This technique allows one to investigate dispersion of nanofillers by the degree of intercalation and/ or exfoliation, in addition to determine the distribution of nanoparticles in the polymer matrix and modifications of the molecular mobility of these fillers. The nanostructured materials obtained with the clays presented good dispersion and formation of mixed nanomaterials, with different degrees of intercalation and exfoliation. The mobility of the material decreased upon adding silica in the starch matrix, which applied to both types of silica. From the TGA technique, a slight increase in thermal stability of the nanocomposite was noted in relation to the starch matrix. Keywords: Starch, nanocomposites, low-field NMR. IntroduçãoProdutos plásticos preparados a partir de polímeros sintéticos são amplamente utilizados em diversas áreas. Estes materiais não são facilmente degradáveis e causam sérios problemas ambientais. Nos últimos anos, os bioplásticos tiveram um grande interesse devido ao aumento da consciência em relação ao desenvolvimento sustentável [1][2][3][4][5] . O amido, um dos polímeros nat...

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“…PLA can be obtained from renewable resources, however, it is a brittle material which represents an important handicap for further applications in biomedical area, packaging, industrial and agricultural fields 6 . On the other hand, PCL is characterized by a relatively low glass transition temperature (~60 °C); thus, at room temperature it behaves as a tough plastic 7 . PLA and PCL copolymers have been developed in order to take advantage of synergistic improvement in properties offered by both polymers 8 .…”

Section: Introductionmentioning

confidence: 99%

Biodegradable Copolymers Obtained by Solution Polymerization

Miranda

Souza²,

Tomaz

et al. 2015

Mat. Res.

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This study aims the synthesis of copolymers of poly (l-lactic acid) and polycaprolactone by ring opening polymerization. The reactions between l-lactide (LLA) and ε-caprolactone (CL) monomers, in 100/0, 95/5, 90/10 and 80/20 LLA/CL mass ratios, were conducted in refluxing toluene, using Stannous octoate as iniciator, methanol as co-iniciator and inert atmosphere (N 2 ). The reaction medium was maintained under stirring at 120 °C for 24 hours. The samples were characterized by carbon-13 and proton nuclear magnetic resonance (C 13 -NMR and H 1 -NMR), and gel permeation chromatography (GPC). Monomers were characterized by thermogravimetry (TG). Copolymers were formed only in samples containing 20 wt% ε-caprolactone. NMR spectra of the other samples showed no evidence of CL units. This fact may be associated with the low-temperature volatilization of monomers. The GPC analysis showed that the increase of CL concentration decrease the molecular weight of copolymers.

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Inorganic-organic hybrids based on poly (ε-Caprolactone) and silica oxide and characterization by relaxometry applying low-field NMR

Cited by 38 publications

References 35 publications

The Development and Characterization of Polycaprolactone and Titanium Dioxide Hybrids

The Development and Characterization of Polycaprolactone and Titanium Dioxide Hybrids

Desenvolvimento de Nanocompósitos à base de Amido de Batata

Biodegradable Copolymers Obtained by Solution Polymerization

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