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

Miranda, Vinícus R.; Carvalho, Antônio J. F.

doi:10.1590/s0104-14282011005000067

Cited by 23 publications

(19 citation statements)

References 33 publications

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“…With the addition of TA (sample S5), the disruption of starch granules is facilitated, and the compatibility between the polymer phases is improved, which has resulted in films with a continuous and more homogeneous matrix. Similar results were obtained by Miranda and Carvalho [26] , who compatibilised blends that contained thermoplastic starch and low-density polyethylene using citric acid, and by Olivato et al [27] , who included citric acid in blends of starch/PBAT.…”

Section: Analysis Of the Results And The Simultaneous Optimisationsupporting

confidence: 81%

Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

Olivato¹,

Grossmann²,

Bilck³

et al. 2013

Polímeros

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Blends of starch/polyester have been of great interest in the development of biodegradable packaging. A method based on multiple responses optimisation (Desirability) was used to evaluate the properties of tensile strength, perforation force, elongation and seal strength of cassava starch/poly(butylene adipate-co-terephthalate) (PBAT) blown films produced via a one-step reactive extrusion using tartaric acid (TA) as a compatibiliser. Maximum results for all the properties were set as more desirable, with an optimal formulation being obtained which contained (55:45) starch/PBAT (88.2 wt. (%)), glycerol (11.0 wt. (%)) and TA (0.8 wt. (%)). Biodegradable plastic bags were produced using the film with this formulation, and analysed according to the standard method of the Associação Brasileira de Normas Técnicas (ABNT). The bags exhibited a 45% failure rate in free-falling dart impact tests, a 10% of failure rate in dynamic load tests and no failure in static load tests. These results meet the specifications set by the standard. Thus, the biodegradable plastic bags fabricated with an optimised formulation could be useful as an alternative to those made from non-biodegradable materials if the nominal capacity declared for this material is considered.

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Section: Analysis Of the Results And The Simultaneous Optimisationsupporting

confidence: 81%

Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

Olivato¹,

Grossmann²,

Bilck³

et al. 2013

Polímeros

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“…O aumento discreto de intensidade da banda a 1205 cm , 2924 cm -1 e na região entre 3200 e 3500 cm -1 [29] . Estas bandas indicam que não ocorreram alterações nas amostras de amido modificado, em virtude da baixa concentração de AC adicionado às pré-misturas.…”

Section: Espectroscopia De Absorção No Infravermelho (Ftir)unclassified

“…Isto sugere que, além de provocar a cisão molecular do amido, o plastificante também foi capaz de esterificá-lo (evidenciado pela banda em ~1730-1735 cm -1 ). Esta reação de esterificação é tipicamente observada para temperaturas acima de 170/180 °C, o que permite concluir que o calor gerado pelas forças de cisalhamento atingiu temperaturas bem superiores a 130 °C durante o processamento [29] .…”

Section: Espectroscopia De Absorção No Infravermelho (Ftir)unclassified

Obtenção de amidos termoplásticos para a extrusão de pós cerâmicos

et al. 2016

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ResumoPolímeros termoplásticos podem ser utilizados como veículo orgânico (VO) em processos de conformação de peças cerâmicas por extrusão. Neste contexto, termoplásticos à base de amido surgem como uma alternativa sustentável ao emprego das poliolefinas convencionalmente utilizadas na formulação de pastas cerâmicas. O passo inicial para o desenvolvimento de um feedstock (carga extrudável) é a seleção adequada do sistema polimérico ligante, o qual é responsável por conferir propriedades reológicas adequadas durante o processamento. O presente trabalho se propôs a caracterizar termoplásticos a base de amido obtidos na presença de ácido cítrico e avaliar o potencial de utilização destes materiais na extrusão de pós cerâmicos. A processabilidade das pré-misturas de amido foi avaliada em extrusora dupla-rosca e em reômetro de torque. A variação dos teores de água e glicerol na composição das pré-misturas de amido influenciou significativamente as interações entre as cadeias poliméricas, promovendo alterações nos valores de densidade e de viscosidade para a maior parte das amostras analisadas. O amido foi parcialmente esterificado como efeito da ação do ácido cítrico no sistema. Dentre as formulações investigadas, a amostra hidratada e processada com 34% p/p de glicerol (H-34) foi a que apresentou as melhores propriedades de pasta, podendo ser futuramente empregada em processos de conformação de pós cerâmicos. Palavras-chave: amido termoplástico, ácido cítrico, extrusão, veículo organico, pós cerâmicos. AbstractThermoplastic polymers can be used as organic vehicle (OV) in ceramic parts forming by extrusion. In this context, starch-based thermoplastics arise as a sustainable alternative to polyolefins conventionally used in ceramic slurry formulation. The initial step for the development of a feedstock (extrudable load) is the selection of the polymeric binder system, which is responsible for providing appropriate rheological properties during processing. Accordingly, in this work thermoplastic starches obtained in the presence of citric acid are characterized and evaluated as for the potential use in the extrusion of ceramic powders. The processability of the premixed starches was investigated in a twin-screw extruder and in a mixer torque rheometer. The variation of water and glycerol contents in the composition of the premixed starches significantly influenced the interactions between polymer chains, promoting changes in density and viscosity for most analysed samples. The thermoplastic starches were partly esterified as an effect of the citric acid presence in the system. Among all formulations investigated, the H-34 sample (hydrated and processed with 34% w/w of glycerol content) showed the best paste properties and can be further employed in ceramic powder forming processes.

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“…Reactive extrusion has been successfully applied to TPS polymers 1 and has resulted in more flexible and less brittle TPS materials 5,[26][27][28][29] when compared to similar TPS materials obtained by conventional extrusion. However, few studies have investigated reative extrusion under edible acids and fewer have examined the use of reactive extrusion on cationic starch bio-based polymers 15 and even less have studied high methoxyl pectin polymers or pectin-starch composites and neither are information about such polymers mechanical or barrier performance.…”

Section: Introductionmentioning

confidence: 99%

“…Cationic and in natura starches were added to pectin in order to evaluate both starches polymers water susceptibility and mechanical properties, when blended by reactive extrusion with pectin in presence of citric acid. Besides of the edible and nontoxic characteristics of citric acid, its utilization is justified also due to pectin ability in forming gel at low pH (normally using citric acid), in presence of high temperature [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] . …”

mentioning

confidence: 99%

Water Susceptibility and Mechanical Properties of Thermoplastic Starch–Pectin Blends Reactively Extruded with Edible Citric Acid

et al. 2016

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IntroductionEco-friendly materials has emerged as one of the most reliable and promising solutions for the food and drug packaging next generation [1][2][3] . In this context, thermoplastic starch (TPS) 4-11 and pectin [12][13][14][15] are promising bases for polymers manufacture due to their wide availability, low cost, renewable character and ability of being produced using traditional processing techniques used in the plastics industry, such as extrusion.TPS and pectin polymer blends have been successfully developed resulting in good mechanical properties and oxygen barrier properties polymers [16][17][18][19][20][21] , especially regarding high methoxyl pectin. Furthermore, the association between cationic TPS and pectin has also been examined in various studies 22,23 . Cationic starch and high methoxyl pectin may interact favourably with one another due to the cationic nature of TPS and the anionic nature of the high methoxyl pectin. According to Prado and Matulewicks 24 , the combination of cationic polysaccharides with anionic polymers can lead to interpolyeletrolyte complexes (IPECs) with hydrogel like structures, with the possibility of producing a hydrogel physically cross-linked with in natura sources molecules. Such possibility has a great impact in developing food contact polymers, once conventional crosslinking processes usually uses toxic compounds, such as epichlorohydrin [24][25] .Reactive extrusion has been successfully applied to TPS polymers 1 and has resulted in more flexible and less brittle TPS materials 5,26-29 when compared to similar TPS materials obtained by conventional extrusion. However, few studies have investigated reative extrusion under edible acids and fewer have examined the use of reactive extrusion on cationic starch bio-based polymers 15 and even less have studied high methoxyl pectin polymers or pectin-starch composites and neither are information about such polymers mechanical or barrier performance. Cationic and in natura starches were added to pectin in order to evaluate both starches polymers water susceptibility and mechanical properties, when blended by reactive extrusion with pectin in presence of citric acid. Besides of the edible and nontoxic characteristics of citric acid, its utilization is justified also due to pectin ability in forming gel at low pH (normally using citric acid), in presence of high temperature [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] . Materials and Methods MaterialsIn natura (not modified) (NM) and cationic (C) corn starch materials were obtained from Unilever Brasil Alimentos Ltda and Corn Products Brazil, respectively. The cationic starch (FH5804) was substitution degree of 0,036% and an Pectin and starch are edible, non-toxic, biodegradable and obtained from renewable sources. Also have the benefit to be easily cross-linked producing hydrogels. Reactive extrusion with edible citric acid and cross linking interactions was evaluated on extruded thermoplastic in natura and cationic starch-pectin blends. Materials w...

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

Cited by 23 publications

References 33 publications

Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

Obtenção de amidos termoplásticos para a extrusão de pós cerâmicos

Water Susceptibility and Mechanical Properties of Thermoplastic Starch–Pectin Blends Reactively Extruded with Edible Citric Acid

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