Reologia de polietileno de alta densidade tenacificado com polietileno elastomérico

Guimarães, Marcos Duarte; Coutinho, Fernanda M. B.; Rocha, Marisa Cristina Guimarães; Bretas, Rosário Elida Suman; Farah, Marcelo

doi:10.1590/s0104-14282003000200013

Cited by 7 publications

(6 citation statements)

References 16 publications

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“…Figure 2 shows that the three polypropylenes present the typical pseudoplastic behavior, with the viscosity decreasing with the increase of the angular frequency. [ 29 ] The presence of branches in the BPP results in a not well‐defined Newtonian plateau at low frequencies. This behavior can be attributed to the existence of complex and branched molecular structures and the influence of their long periods of relaxation.…”

Section: Resultsmentioning

confidence: 99%

Non‐isothermal Crystallization Kinetics, Thermal, and Rheological Behavior of Linear/Branched Polypropylene Blends

Macedo

Campos

Lima

et al. 2022

Macromolecular Symposia

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This work aims at evaluating the rheological and thermal properties and non‐isothermal crystallization kinetics of blends of linear homopolymer polypropylene (HPP) and branched polypropylene (BPP). Two linear polypropylene's of different melt flow index (MFI) are used: H301 (10 g per 10 min) and H604 (1.5 g per 10 min); and one BPP (2 g pr 10 min). The rheological result shows that the H301/BPP blends have an increase in complex viscosity proportional to the addition of BPP amount, while for the H604/BPP blends, it is observed a higher influence of H604 on rheological properties. With the addition of 25 wt% of BPP, the strain hardening behavior is observed in the extensional rheology tests of the polymer blend. The DSC results show that the melt temperature and the crystallinity content in blends with BPP are affected by the molecular weight (MW) of the linear polymer. Results suggest that Pseudo‐Avrami/Jeziorny and Mo models can be used to predict the experimental results of crystallization kinetics of the blends with sufficient precision for all systems studied, regardless of MW. Therefore, it is possible to use the blends of HPP/BPP in processes that demand a combination of rheological properties, such as high strain hardening, and fast crystallization.

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Section: Resultsmentioning

confidence: 99%

Non‐isothermal Crystallization Kinetics, Thermal, and Rheological Behavior of Linear/Branched Polypropylene Blends

Macedo

Campos

Lima

et al. 2022

Macromolecular Symposia

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“…From the FTIR analyses, it was possible to identify the PE characteristic bands, i.e., stretching between 2950 and 2850 cm −1 ; bending between 2950 and 2850 cm −1 ; rocking close to 700 cm −1 [11]. It was observed both in the spectrum of the HDPE sample, as received, as well as in the spectra of the specimens at all three temperatures, discrete bands between 965 and 946 cm −1 , which indicate the presence of vinyl groups, as they absorb between 990 and 910 cm −1 [12].…”

Section: Results and Discussmentioning

confidence: 99%

Rheological and Thermal Behavior of High-Density Polyethylene (HDPE) at Different Temperatures

Erbetta¹,

Manoel²,

Oliveira³

et al. 2014

MSA

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In the present work, rheological properties of HDPE samples were measured at temperatures of 150˚C, 190˚C and 230˚C. It was shown, by oscillatory tests, at low frequencies, that, for temperatures of 150˚C and 190˚C, there was a predominance of the viscous behavior over the elastic one. At 230˚C, there was a predominance of the elastic contribution, and there was an increase of the molar mass compared with the ones obtained from the tests at 150˚C and 190˚C. The results obtained from the temperature ramp oscillatory test showed that, up to around 248°C, the viscous behavior prevailed, the opposite being observed at higher temperatures. At 230˚C the sample showed significantly lower values of strain when compared with the ones observed at 150˚C and 190˚C. Oxidative induction time (OIT), melting point and degree of crystallinity were determined by differential scanning calorimetry (DSC). The DSC results and the rheological measurements showed a completely different behavior for the HDPE samples at 230˚C compared with the 150˚C and the 190˚C ones, suggesting that HDPE, at the temperature of 230˚C, underwent thermo-oxidative degradation with the initial predominance of crosslinking.

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“…Foi utilizado um reômetro Haake Viscotester 550 com sistema cone placa e sensor PK100D. A taxa de cisalhamento foi aumentada gradualmente de 0 a 300 s -1 em 60 s, mantida a 300 s -1 por 30 s e reduzida até 0 s -1 em 60 s. Desta maneira avaliou-se o comportamento viscoelástico da suspensão e a recuperação da viscosidade pela diferença entre as curvas de aumento e de redução da taxa de cisalhamento [9]. O ensaio foi conduzido a temperatura constante de 22 °C.…”

Section: Ensaio De Viscosidadeunclassified

Análise estatística da influência dos parâmetros de processamento na planicidade de placas de zircônia estabilizada com 8%mol de ítrio obtidas por colagem de fita

Sigeiro,

Marcomini

2023

Matéria (Rio J.)

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RESUMO No presente estudo, lotes de placas de zircônia estabilizada com 8% mol de ítrio (TZ8Y) foram fabricados pela técnica de colagem de fita, variando entre eles a composição da suspensão, como o volume de sólidos e os teores de ligantes, de plastificante do tipo I e de plastificante do tipo II com o intuito de verificar a influência destes parâmetros e do comportamento tixotrópico da suspensão sobre o empenamento do produto final. Após sinterizadas, a topografia das placas foi mapeada por meio de um relógio comparador, tomando medidas sobre a superficia das placas em um sistema de coordenadas, e, a partir desse sistema, foi definido um índice numérico que quantifica a planicidade das amostras. A influência foi investigada através de uma análise estatística bivariada, relacionando o índice de planicidade com cada um dos parâmetros alvo. A análise apresentou uma correlação negativa forte e significativa pelo teste de Spearman (⍴ ≅ 0,95 e valor-p < 10–3) entre o teor de plastificante do tipo I e a planicidade das placas produzidas, porém para os outros parâmetros analisados a correlação não pôde ser considerada estatisticamente significativa. Além disso, os resultados mostraram também que a utilização de um pós processamento nas fitas à verde, como uma laminação, melhorou substancialmente a planicidade das placas após a sinterização.

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Reologia de polietileno de alta densidade tenacificado com polietileno elastomérico

Cited by 7 publications

References 16 publications

Non‐isothermal Crystallization Kinetics, Thermal, and Rheological Behavior of Linear/Branched Polypropylene Blends

Non‐isothermal Crystallization Kinetics, Thermal, and Rheological Behavior of Linear/Branched Polypropylene Blends

Rheological and Thermal Behavior of High-Density Polyethylene (HDPE) at Different Temperatures

Análise estatística da influência dos parâmetros de processamento na planicidade de placas de zircônia estabilizada com 8%mol de ítrio obtidas por colagem de fita

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