Blend morphology development during melt flow: Correlation of a model concept based on dynamic phase volume with practical observations

Namhata, S.; Guest, M; Aerts, L.

doi:10.1002/(sici)1097-4628(19990110)71:2<311::aid-app15>3.0.co;2-3

Cited by 16 publications

(7 citation statements)

References 14 publications

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“…Os autores atribuíram esses resultados à presença de uma morfologia do tipo co-contínua. De forma semelhante, Guest et al [25] estudaram o comportamento dinâmico-mecânico de PC/ABS, observando uma queda acentuada na intensidade de tan δ, referente ao pico de Tg do PC, quando a composição deste era de 70%. Os autores sugeriram que a fase PC não estava mais na forma contínua e deste modo contribuía de forma menos significativa para a tan δ.…”

Section: Resultsunclassified

Morfologia Co-Contínua na Mistura Poliestireno/Copolímero de Etileno-Acetato de Vinila

2002

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Misturas de PS/EVA, preparadas sob diferentes condições numa câmara de mistura interna, foram avaliadas quanto ao grau de continuidade ou co-continuidade de fases. Três técnicas foram empregadas: ensaio de extração seletiva, microscopia eletrônica de varredura (SEM) e análise térmica dinâmico-mecânica (DMTA). As diferentes temperaturas empregadas no processamento das misturas afetam substancialmente a faixa de co-continuidade e o ponto de percolação. Pôde-se observar que temperaturas mais altas de processamento acarretam num estreitamento da faixa de co-continuidade. As misturas PS/EVA na composição 60/40 %vol apresentaram uma morfologia do tipo co-contínua, independente da temperatura empregada no processamento ou do tipo de EVA. Na composição complementar, PS/EVA (40/60 % vol), a morfologia passa a ser dependente tanto da temperatura de processamento como do tipo de EVA empregado. As morfologias obtidas por SEM confirmaram os resultados obtidos nos ensaios de extração seletiva. A técnica de DMTA mostrou ser uma boa alternativa para correlacionar estrutura molecular e morfologia.

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Section: Resultsunclassified

Morfologia Co-Contínua na Mistura Poliestireno/Copolímero de Etileno-Acetato de Vinila

2002

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“…The morphology of immiscible or partially miscible polymer blends depends on several factors, such as the rheological properties (viscosity ratio) of blend partners, blend composition, interfacial tension between blend partners, and processing conditions [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Taylor et al and Grace et al investigated the effect of viscosity ratio λ = η d /η m on the size of the dispersed phase of immiscible fluids in general, where η d is the viscosity of the dispersed phase and η m the viscosity of the matrix phase [ 11 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

“…In the core the melt experiences lower shear forces during injection molding and, obviously, a lower cooling rate due to the larger distance from the cold mold surface. This allows the dispersed phase to undergo relaxation, whereby a more dispersed droplet-like structure results and is eventually frozen [ 2 , 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Morphology Formation in PC/ABS Blends during Thermal Processing and the Effect of the Viscosity Ratio of Blend Partners

et al. 2016

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Morphology formation during compounding, as well as injection molding of blends containing 60 wt % polycarbonate (PC) and 40 wt % polybutadiene rubber-modified styrene-acrylonitrile copolymers (ABS), has been investigated by transmission electron microscopy (TEM). Profiles of the blend morphology have been recorded in injection-molded specimens and significant morphology gradients observed between their skin and core. A <10 µm thick surface layer with strongly dispersed and elongated nano-scale (streak-like) styrene acrylonitrile (SAN) phases and well-dispersed, isolated SAN-grafted polybutadiene rubber particles is followed by a 50–150 µm thick skin layer in which polymer morphology is characterized by lamellar SAN/ABS phases. Thickness of these lamellae increases with the distance from the specimen’s surface. In the core of the specimens the SAN-grafted polybutadiene rubber particles are exclusively present within the SAN phases, which exhibit a much coarser and less oriented, dispersed morphology compared to the skin. The effects of the viscosity of the SAN in the PC/ABS blends on phase morphologies and correlations with fracture mechanics in tensile and impact tests were investigated, including scanning electron microscopy (SEM) assessment of the fracture surfaces. A model explaining the mechanisms of morphology formation during injection molding of PC/ABS blends is discussed.

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“…In the past decades, the effect of shear flow on the morphology and phase behavior in immiscible polymer blends is of considerable interest to polymer science and engineering 1–16. Break‐up17, 18 and coalescence19, 20 of the dispersed droplets were two contrary trends in the melt blending.…”

Section: Introductionmentioning

confidence: 99%

Online study of the formation of PA6 droplets in PP matrix under shear flow

Yang¹,

Zhu

Jiang

2007

J of Applied Polymer Sci

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Breakup process of polyamide 6 (PA6) in polypropylene (PP) matrix under shear flow was online studied by using a Linkam CSS 450 stage equipped with optical microscopy. Both tip streaming and fracture breakup modes of PA6 droplets were observed in this study. It was reported that the droplet would break up by tip streaming model when the radio of the droplet phase viscosity to the matrix phase viscosity ( 1934, 146, 501; Grace, Chem Eng Commun 1982, 14, 225; Bartok and Mason, J Colloid Sci 1959, 14, 13; Rumscheidt and Mason, J Colloid Sci 1961, 16, 238; de Bruijn, Chem Eng Sci 1993, 48, 277). However, the tip streaming model was observed even when the viscosity ratio was much greater than 0.1 (Z r ¼ 1.9). In this study for the tip streaming mode, small droplets were ruptured from the tip of the mother droplet. On the other hand, the mother droplet was broken into two or more daughter droplets with one or several satellite droplets between them for the fracture mode. It was found that PA6 droplet was much elongated at first, and then broke up via tip streaming or fracture to form daughter droplets or small satellite droplets with the shape of fiber or ellipse. Stopping shearing, those elongated droplets began to shrink, and finally became spheres. Moreover, it was found that the average domain size of those PA6 spheres considerably decreased with increasing shear time.

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Blend morphology development during melt flow: Correlation of a model concept based on dynamic phase volume with practical observations

Cited by 16 publications

References 14 publications

Morfologia Co-Contínua na Mistura Poliestireno/Copolímero de Etileno-Acetato de Vinila

Morfologia Co-Contínua na Mistura Poliestireno/Copolímero de Etileno-Acetato de Vinila

Morphology Formation in PC/ABS Blends during Thermal Processing and the Effect of the Viscosity Ratio of Blend Partners

Online study of the formation of PA6 droplets in PP matrix under shear flow

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