Effects of different thermoplastic binders on the processability of feedstocks for ceramic co-extrusion process

Ismael, M. R.; Clemens, Frank; Graule, Thomas; Hoffmann, Michael J.

doi:10.1016/j.ceramint.2011.05.084

Cited by 21 publications

(9 citation statements)

References 24 publications

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“…Processamento em extrusora dupla-rosca Estes resultados estão de acordo com as propriedades reológicas de ligantes comerciais previamente descritas na literatura [22] . A processabilidade de quatro termoplásticos comerciais [poliestireno, polietileno de baixa densidade, poli(etileno-co-etil acrilato) e blenda de poli(etileno-co-etil acrilato) e poli(isobutilmetacrilato)] foi investigada durante a formulação de feedstocks para a extrusão de titanato zirconato de chumbo (PZT).…”

Section: Amostra Processamento Em Câmara De Misturaunclassified

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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Section: Amostra Processamento Em Câmara De Misturaunclassified

Obtenção de amidos termoplásticos para a extrusão de pós cerâmicos

et al. 2016

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“…However, as noted by Ismael et al, 34 this model is not always well applicable for the injection moulding compounds, and the slurry behaviour depends on the type of ceramic powders. Lower viscosity with a noted high solid content may be achieved by the optimised addition and mixing of the binder with solid materials and appropriate handling of the slurry (e.g.…”

Section: Binder System For Low Pressure Injection Mouldingmentioning

confidence: 99%

Low pressure injection moulding mass production technology of complex shape advanced ceramic components

Medvedovski

Peltsman²

2012

Advances in Applied Ceramics

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This paper summarises and reviews the industrial manufacturing experience of ceramic components with custom designed complex shapes using low pressure injection moulding technology during a number of years. This technology is successfully used for manufacturing advanced ceramics with different compositions and for different applications. A production level is achieved with hundreds of pieces/day or week or higher. The major principles of this technology are reviewed based on the extensive processing experience. Some processing features, which affect the quality of ceramics and processing yield, are pointed out, particularly for industrial processing. Semi-and automated equipment for low pressure injection moulding technology providing high productivity are described.

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“…e purpose was to evaluate the matrix-fibre interaction, debonding energy [15], and correlation with the electromechanical coupling factor. e big advantage of fibre transducers against dice and fill composites is the realization of longer length/diameter ratios which result in a higher coupling factor and lower frequency ultrasonic devices [16].…”

Section: Introductionmentioning

confidence: 99%

Effect of Polymer‐Ceramic Fibre Interphase Design on Coupling Factor in Low Fibre Volume Content Piezoelectric Composites

Lusiola

Oberle

Gorjan

et al. 2018

Advances in Materials Science and Engineering

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In this work, we investigated different short molecule polymer coatings in piezoelectric ceramic-polymer composites with low fibre volume contents. Modifying the interphase between the piezoelectric PZT (lead zirconate titanate) fibre and the epoxy matrix thus enhances the electromechanical coupling factor for 1–3 ultrasound transducers with low fibre contents. It is known that the electromechanical coupling factor can be increased by precoating a ceramic fibre with a soft interlayer polymer [1-1-3]. In this paper, we investigate the so-called 1-1-1-3 composites composed of a ferroelectric ceramic fibre (core), a soft polymer layer (e.g., fatty acids, amides, waxes, or oils), an epoxy resin shell, and an epoxy resin matrix. Some soft polymer layers allowed the free movement of the ferroelectric fibres reducing blocking or clamping by the inactive polymeric matrix, resulting in higher electromechanical coupling factors (kt) for composites with low fibre volume contents. Using an oil-based interlayer, the dielectric constant can be significantly increased. The lowest fibre push-out stress could be achieved with the paraffin interlayer; however, no correlation with the coupling factor could be observed.

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Effects of different thermoplastic binders on the processability of feedstocks for ceramic co-extrusion process

Cited by 21 publications

References 24 publications

Obtenção de amidos termoplásticos para a extrusão de pós cerâmicos

Obtenção de amidos termoplásticos para a extrusão de pós cerâmicos

Low pressure injection moulding mass production technology of complex shape advanced ceramic components

Effect of Polymer‐Ceramic Fibre Interphase Design on Coupling Factor in Low Fibre Volume Content Piezoelectric Composites

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