Gamma irradiation effects on poly(hydroxybutyrate)

Oliveira, Letícia Maria de; Araújo, Elmo S.; Guedes, S.M.L.

doi:10.1016/j.polymdegradstab.2006.01.008

Cited by 64 publications

(29 citation statements)

References 16 publications

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“…Our results indicated a degree of crystallinity of 53%. This method was previously used to assess the crystalline fraction of as-supplied Brazilian PHB with similar results [53]. PHB/PANI-HCl nanocomposites II and IV diffraction patterns are very close to those exhibited by neat PHB (Figures 4b and 4c).…”

Section: Xrd Analysissupporting

confidence: 59%

“…Irradiation with gamma rays provokes main chain scissions in PHB structure. In the range of 0-50 kGy, the G value (number of scissions per 100 eV of absorbed energy) for BIOCYCLE ® is 15.7 [53]. This number of scissions is large enough to reduce the initial molar mass in one order of magnitude after a 25 kGy absorbed dose.…”

Section: Biodegradability Of Phb/pani-hcl Nanocompositementioning

confidence: 98%

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Biodegradable conductive composites of poly(3-hydroxybutyrate) and polyaniline nanofibers: Preparation, characterization and radiolytic effects

Araújo¹,

Ferreira²,

Araújo³

2011

Express Polym. Lett.

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Poly(3-hydroxybutyrate) is a biodegradable polyester produced by microorganisms under nutrient limitation conditions. We obtained a biodegradable poly(3-hydroxybutyrate) composite having 8 to 55% of chemically in situ polymerized hydrochloric acid-doped polyaniline nanofibers (70-100 nm in diameter). Fourier transform infrared spectroscopy and X-rays diffractometry data did not show evidence of significant interaction between the two components of the nanocomposite, and polyaniline semiconductivity was preserved in all studied compositions. Gamma-irradiation at 25 kGy absorbed dose on the semiconductive composite presenting 28% of doped polyaniline increased its conductivity from 4.6*10-2 to 1.1 S/m, while slightly decreasing its biodegradability. PANI-HCl biodegradation is negligible when compared to PHB biodegradability in an 80 day timeframe. Thus, this unprecedented all-polymer nanocomposite presents, at the same time, semiconductivity and biodegradability and was proven to maintain these properties after gamma irradiation. This new material has many potential applications in biological science, engineering, and medicine

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Section: Xrd Analysissupporting

confidence: 59%

Section: Biodegradability Of Phb/pani-hcl Nanocompositementioning

confidence: 98%

Biodegradable conductive composites of poly(3-hydroxybutyrate) and polyaniline nanofibers: Preparation, characterization and radiolytic effects

Araújo¹,

Ferreira²,

Araújo³

2011

Express Polym. Lett.

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“…Entretanto, sua fragilidade e baixa estabilidade térmica têm limitado sua aplicação [4] . Assim sendo, novas abordagens, como a produção de blendas, estão sendo estudadas [5,6] .…”

Section: Introductionunclassified

Efeito da incorporação de nanopartículas de TiO2 na estrutura e propriedades de blendas de polipropileno e poli(hidroxibutirato) submetidas a testes de envelhecimento acelerado

2014

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Resumo: O polipropileno (PP) tem uma degradação natural lenta e representa um importante constituinte na gestão dos resíduos sólidos, enquanto o poli(hidroxibutirato) (PHB) é um polímero biodegradável, mas tem as desvantagens de dificuldade de processamento e custo. O objetivo deste trabalho foi avaliar o efeito de nanopartículas de TiO 2 , do método de processamento e do envelhecimento acelerado na estrutura e propriedades da mistura PP/PHB/TiO 2 . As amostras foram produzidas por etapas de extrusão e injeção e foram caracterizadas por MEV/EDS, FTIR e análise térmica. Os resultados mostraram que a incorporação de 3% de nanopartículas de TiO 2 levou a um aumento do tamanho médio da fase dispersa rica em PHB. A mudança na sequência da adição de nanopartículas de TiO 2 permitiu guiar a incorporação desses nanocomponentes para a fase rica em PP. As misturas produzidas se mostraram mais estáveis termicamente do que PHB puro e a adição de TiO 2 foi eficaz em aumentar a estabilidade térmica dos compósitos. As análises termogravimétricas e por FTIR mostraram que blendas contendo nanopartículas de TiO 2 tiveram sua degradação mais afetada nos ensaios de envelhecimento acelerado. Os ensaios de extração com solvente mostraram que um maior conteúdo de produtos de fotodegradação puderam ser extraídos de amostras contendo mais elevadas concentrações de TiO 2 . Palavras-chave: Polipropileno(PP), poli(hidroxibutirato) (PHB), compósitos, TiO 2 . Effect of the Incorporation of TiO 2 Nanoparticles on the Behavior of Polypropylenepoly(hydroxybutyrate) Blends Submitted to Accelerated Aging TestsAbstract: Polypropylene (PP) has a slow natural degradation rate. On the other hand, poly(hydroxybutyrate) (PHB) is biodegradable but has the disadvantages of cost and difficulty of processing. The aim of this work was to evaluate the effect of TiO 2 nanoparticles, processing conditions and accelerated aging on the structure and properties of PP/PHB/ TiO 2 mixtures. Samples were prepared by extrusion and injection molding. The incorporation of 3% TiO 2 nanoparticles led to an increase in the average size of the dispersed phase rich in PHB. Changes in the sequence of TiO 2 nanoparticles incorporation were able to guide the inclusion of nanoparticles to the PP-rich phase. The produced composites were more thermally stable than pure PHB and the incorporation of TiO 2 was effective to increase the thermal stability of the composites. Thermal and FTIR analyses showed that blends containing TiO 2 nanoparticles had their degradation more affected by accelerated aging treatments. Solvent extraction results revealed that a larger amount of soluble products from the photodegradation could be extracted from samples containing TiO 2 submitted to accelerated aging treatments.

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“…X c integration and calculations were performed according to well-established procedures in the literature 13,[29][30][31] . X c was also calculated from DSC.…”

Section: Characterization Methodsmentioning

confidence: 99%

Structural and Thermo-mechanical Evaluation of Two Engineering Thermoplastic Polymers in Contact with Ethanol Fuel from Sugarcane

Silva

Berry²,

Costa

2016

Mat. Res.

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Special polymers have been used in the manufacture of storage structures and pipelines avoiding corrosive processes during ethanol fuel transport/storage. Therefore, this work investigated comparatively the effects of the ethanol on the physical-mechanical properties of poly (ether ether ketone) (PEEK) and polyamide 11 (PA-11) based on ageing tests. The WAXD and DSC results demonstrated slight reductions on the crystallinity degree of the aged PEEK, contrariwise to what happened with PA-11, where X c increased after ageing. However, the results of thermal, thermomechanical and mechanical analysis (TGA, DMTA, tensile and micro-IITs) demonstrated that PEEK is stable and no significant changes were observed in its elastic modulus (E y ≈ 3.4 GPa, E' and E it ≈ 3.7 GPa) or glass transition temperature. PA-11, conversely, was sensitive to ethanol fuel and expressive changes of its physicalmechanical properties were verified. For both materials, a reasonable correlation between crystallinity and mechanical properties was established.

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Gamma irradiation effects on poly(hydroxybutyrate)

Cited by 64 publications

References 16 publications

Biodegradable conductive composites of poly(3-hydroxybutyrate) and polyaniline nanofibers: Preparation, characterization and radiolytic effects

Biodegradable conductive composites of poly(3-hydroxybutyrate) and polyaniline nanofibers: Preparation, characterization and radiolytic effects

Efeito da incorporação de nanopartículas de TiO2 na estrutura e propriedades de blendas de polipropileno e poli(hidroxibutirato) submetidas a testes de envelhecimento acelerado

Structural and Thermo-mechanical Evaluation of Two Engineering Thermoplastic Polymers in Contact with Ethanol Fuel from Sugarcane

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