Gelatinisation of starches of different amylose/amylopectin content. A study by differential scanning calorimetry

Russell, Peter L.

doi:10.1016/s0733-5210(87)80050-4

Cited by 158 publications

(82 citation statements)

References 35 publications

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“…Essas características associadas à recristalização após o processamento [9] e elevada viscosidade do material fundido tem impedido um maior crescimento do seu uso. Uma das formas encontradas para melhorar as propriedades do amido e que tem sido empregada com sucesso na produção de produtos industriais é a composição do amido com outros polímeros para dar origem a blendas poliméricas [5,[10][11][12][13][14][15][16] . Comparada ao desenvolvimento de novos materiais, as blendas apresentam baixo custo, e conferem grande versatilidade à indústria de transformação de plástico.…”

Section: Introductionunclassified

Blendas compatíveis de amido termoplástico e polietileno de baixa densidade compatibilizadas com ácido cítrico

Miranda

Carvalho

2011

Polímeros

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Resumo: Blendas de polietileno de baixa densidade (PEBD) e amido termoplástico (TPS) modificado foram preparadas via extrusão reativa (REX) e caracterizadas por microscopia eletrônica de varredura (MEV), espectroscopia na região do infravermelho com transformada de Fourier (FTIR), absorção de umidade em ambiente com 53% de umidade relativa e difração de raios-X. Em uma primeira etapa, foi preparado o TPS-modificado, via REX a partir de uma mistura de amido de milho, ácido cítrico e glicerol. As blendas TPS-PEBD foram preparadas pelo processamento de uma mistura do TPS modificado e PEBD, ambos em peletes, em uma extrusora de rosca simples. Foi observado um significativo efeito de compatibilização, atribuído especialmente à redução da viscosidade da fase TPS e consequente redução da tensão interfacial entre as fases de TPS e PEBD. Os espectros de FTIR apresentaram deslocamentos de bandas de absorção do amido confirmando o efeito de compatibilização pelo ácido cítrico. Observou-se também significativa alteração da morfologia das blendas, especialmente para as blendas preparadas com adição de 1,0 -1,5 % de ácido cítrico, que apresentaram estrutura da fase dispersa mais fina e homogênea. Palavras-chave: Amido termoplástico, blendas biodegradáveis, polietileno, extrusão reativa, compatibilização. Compatible Blends of Thermoplastic Starch and Low Density Polyethylene Compatibilized with Citric AcidAbstract: Blends of citric acid-modified thermoplastic starch (TPS) and low density polyethylene (LDPE) were prepared by reactive extrusion (REX) and characterized by scanning electron microscopy (SEM) of the fragile fracture surfaces, Fourier-transform infrared spectroscopy (FTIR), water absorption in 53% relative humidity environment and by X-ray diffraction. The modified TPS was prepared by the reactive extrusion of a mixture of corn starch, citric acid and glycerol (30%). TPS-LDPE blends were then prepared by the processing of TPS and PEBD both in pellets in a single screw extruder. It was observed an important compatibilization effect, attributed to the reduction of TPS melt viscosity and consequently the reduction of the interfacial tension between TPS and PEBD phases. The FTIR spectra showed shifting of starch bands confirming the compatibilization effect of citric acid. Important change on blend morphology as function of the TPS modification were observed, in particular for the blends prepared with the addition of 1,0 -1,5% AC which showed a more homogeneous and finer dispersed phase. Keywords: Thermoplastic starch, biodegradable blends, polyethylene, reactive extrusion, compatibilization. IntroduçãoO desenvolvimento de novos materiais poliméricos derivados de fontes renováveis tem motivado um grande número de estudos recentemente. O amido é um dos materiais mais promissores para essa finalidade, pois é produzido em grandes quantidades em praticamente todas as regiões do mundo, tem baixo custo e pode ser utilizado tanto na produção de insumos químicos básicos como diretamente na composição de polímeros termoplásticos ...

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Section: Introductionunclassified

Blendas compatíveis de amido termoplástico e polietileno de baixa densidade compatibilizadas com ácido cítrico

Miranda

Carvalho

2011

Polímeros

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“…In the case of starch gelatinization, the DSC thermograms give the possibility of transition enthalpies occurred during melting of the semicrystallization (or double-helical structure) in the starch as well as precise measurement of the transition temperatures (i.e. onset, T o ; peak, T p ; and conclusion, T c ) (Wootton and Bamunuarachchi 1979;Russell 1987;Sahai and Jackson 1999).…”

Section: Technology Descriptionmentioning

confidence: 99%

“…Since Stevens and Elton first used differential scanning calorimetry (DSC) to measure gelatinization and retrogradation of starch in 1971, DSC has been widely accepted as the most suitable method for the evaluation of starch gelatinization (Eliansson 1986;Russell 1987;Yu and Christie 2001;Tananuwong and Reid 2004). A water-dependent relationship has been established from DSC measurement for the starch endotherms during gelatinization.…”

Section: Applicationsmentioning

confidence: 99%

“…A water-dependent relationship has been established from DSC measurement for the starch endotherms during gelatinization. One single symmetric endotherm, usually denoted by G, is observed in the lower temperature region (54-73°C) for different starches with excess water (Wootton and Bamunuarachchi 1979;Russell 1987). A reduction in the amount of water available causes a biphasic endotherm with a trailing shoulder, M1.…”

Section: Applicationsmentioning

confidence: 99%

“…Recently starches have been used as important raw materials for biodegradable plastics and its gelatinization process has attracted much attention since it acts as an important and unique characterization in the processing of starch-based materials (Lelievre 1974;Lelievre 1976;Biladeris, Page et al 1985;Russell 1987;Svensson and Eliasson 1995).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Starch Gelatinization under Shearless and Shear Conditions

Xie¹,

Liu²,

Chen³

et al. 2007

International Journal of Food Engineering

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This article reviews the development of studying starch gelatinization under shear and shearless conditions, in particular the technologies used to detect the degree of gelatinization. Advantages and disadvantages of each technology were discussed and then some examples were presented to demonstrate their application. A new technology RheoScope, an instrument that can measure viscosity under shear stress and simultaneously observes variation of starch particles using a microscope, was also introduced. It was found the definition of "gelatinization" could be different for different detection technologies. Under shearless condition full gelatinization of starch needs about ratio of water 3/starch 1, while the gelatinization under shear condition requires less water content since shear stress enhances the processing. The number of endotherm and enthalpy of gelatinization depends on amylose/amylopectin, moisture and lipid content.

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Amylose-lipid complex dissociation. A study of the kinetic parameters

Jovanovich

Añón²

1999

Biopolymers

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Gelatinisation of starches of different amylose/amylopectin content. A study by differential scanning calorimetry

Cited by 158 publications

References 35 publications

Blendas compatíveis de amido termoplástico e polietileno de baixa densidade compatibilizadas com ácido cítrico

Blendas compatíveis de amido termoplástico e polietileno de baixa densidade compatibilizadas com ácido cítrico

Starch Gelatinization under Shearless and Shear Conditions

Amylose-lipid complex dissociation. A study of the kinetic parameters

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