A first insight on composites of thermoplastic starch and kaolin

Carvalho, Antônio J. F.; Curvelo, A. A. S.; Agnelli, José Augusto Marcondes

doi:10.1016/s0144-8617(00)00315-5

Cited by 233 publications

(93 citation statements)

References 11 publications

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“…The natural smectite clays, montmorillonite and hectorite, readily formed nanocomposites with thermoplastic starch which prepared by melt-processing of starch and glycerol [136]. In all cases, clay increased the elastic modulus of thermoplastic starch.…”

Section: Starch Nanocompositesmentioning

confidence: 97%

Nanotechnology and its applications in lignocellulosic composites, a mini review

Kamel¹

2007

Express Polym. Lett.

230

107

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Abstract. Nanotechnology has applications across most economic sectors and allows the development of new enabling science. The ability to see materials down to nanoscale dimensions and to control how materials are constructed at the nanoscale is providing the opportunity to develop new materials and products in previously unimagined ways. This review covers the academic and industrial aspects of the preparation, characterization, material properties, crystallization behavior; melt rheology, and processing of polymer/cellulose or cellulose/cellulose nanocomposites. Cellulosic materials have a great potential as nanomaterials because they are abundant, renewable, have a nanofibrillar structure, can be made multifunctional, and self-assemble into well-defined architectures. The fibrillation of pulp fiber to obtain nano-orderunit web-like network structure, called microfibrillated cellulose, is obtained through a mechanical treatment of pulp fibers, consisting of refining and high pressure homogenizing processes. Also, nano-whisker can be used as novel reinforcement in nanocomposites; it can be obtained by acid hydrolysis from various sources such as wood, tunicin, ramie, cotton, wheat straw, bacterial cellulose, and sugar beet. The properties of nanocomposite materials depend not only on the properties of their individual parents, but also on their morphology and interfacial characteristics. Compared with plant cellulose, bacterial cellulose has found many applications in the biomedical field as tissue engineering materials due to their good biocompatibility, mechanical properties similar to those of hard and soft tissue and easy fabrication into a variety of shapes with adjustable interconnected porosity. One of the drawbacks of cellulose whiskers with polar surfaces is poor dispersibility/compatibility with nonpolar solvents or resins. Thus, their incorporation as reinforcing materials for nanocomposites has so far been largely limited to aqueous or polar systems. To overcome this problem and broaden the type of possible polymer matrices, efforts of surface modification have been made. These attempts include surfactant coating or graft copolymerization.

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Section: Starch Nanocompositesmentioning

confidence: 97%

Nanotechnology and its applications in lignocellulosic composites, a mini review

Kamel¹

2007

Express Polym. Lett.

230

107

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“…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 [1][2][3][4][5][6] . O Brasil ocupa papel de destaque na produção de amido sendo o segundo produtor mundial de mandioca, ficando atrás apenas da Nigéria e terceiro produtor mundial de milho, ficando atrás dos Estados Unidos da América e da China [7] .…”

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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“…Furthermore, natural fibers such as flax, ramie, jute, sisal, and cabuya (Wollerdorfer and Bader 1998;Torres 2007) have been proven to enhance performance of TPS. In general, the properties of starch-based products are influenced by many factors which include starch type and form, processing technique, polymer orientation, moisture (relative humidity), amylose content, test procedure, type and method of reinforcement (if any), type and amount of plasticizer, and the kind of composite components (Biliaderis et al 1999;Thunwall et al 2006b;Schlemmer et al 2007;Teixeira et al 2007;Torres et al 2007;De Carvalho et al 2001;Yu and Christie 2005).…”

Section: Introductionmentioning

confidence: 99%

Effects of Incorporating Polycaprolactone and Flax Fiber into Glycerol-Plasticized Pea Starch

et al. 2011

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The environmental menace associated with the existing eco-unfriendly conventional plastics prompted the exploration of natural polymers such as starch for the development of biodegradable plastics. These efforts have seen starch used in various ways, one of which is in the processing of thermoplastic starch (TPS). Thermoplastic starch (also known as plasticized starch) is the product of the interaction between starch and a plasticizer in the presence of thermomechanical energy. While starch blends with conventional plastics only yield products that biofragment, thermoplastic starch (TPS) offers a completely biodegradable option. However, it is limited in application due to its weak mechanical strength and poor moisture resistance. To this end, the objective of this study was to determine the effects of incorporating polycaprolactone (PCL) and flax fiber into glycerol-plasticized pea starch. The effects of processing moisture content on the physical properties of glycerol-plasticized pea starch were also evaluated. The physical properties investigated included morphology, tensile properties, moisture absorption, and thermal properties. Accordingly, two thermoplastic pea starch mixtures containing 9.3 and 20% processing moisture contents were prepared while maintaining starch (pea starch) and glycerol in ratio 7:3 by weight (dry basis). Polycaprolactone was then compounded at 0, 10, 20, 30, and 40% by weight in the solid phase with the TPS mixtures to determine the effects of processing moisture content and PCL incorporation on the physical properties of glycerol-plasticized pea starch.This experiment was structured as a 2 x 5 factorial completely randomized design at 5% level of significance. Subsequently, PCL and flax fiber were iii compounded with the TPS mixture containing 20% processing moisture to determine the effects of PCL (0, 20, and 40% wt) and flax fiber (0, 5, 10, and 15% wt) incorporation on the physical properties of glycerol-plasticized pea starch. This was structured as a 3 x 4 factorial completely randomized design at 5% level of significance. All the samples were compressed at 140°C for 45 min under 25000-kg load. The compression-molded samples were characterized using scanning electron microscopy (SEM), tensile test, moisture absorption test, and differential scanning calorimetry (DSC) techniques.The tensile fracture surfaces showed a moisture-induced fundamental morphological difference between the two TPSs. The TPS prepared at 20% processing moisture content revealed complete starch gelatinization, thus, exhibiting a rather continuous phase whereas the TPS prepared at 9.3% processing moisture content revealed instances of ungelatinized and partly gelatinized pea starch granules. Consequently, the tensile strength, yield strength, Young's modulus, and elongation at break increased by 208.6, 602.6, 208.5, and 292.0%, respectively at 20% processing moisture content. The incorporation of PCL reduced the degree of starch gelatinization by interfering with moisture migration during compr...

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A first insight on composites of thermoplastic starch and kaolin

Cited by 233 publications

References 11 publications

Nanotechnology and its applications in lignocellulosic composites, a mini review

Nanotechnology and its applications in lignocellulosic composites, a mini review

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

Effects of Incorporating Polycaprolactone and Flax Fiber into Glycerol-Plasticized Pea Starch

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