Preparation and crystallization behavior of poly(ethylene 2,5-furandicarboxylate)/cellulose composites by twin screw extrusion

ABSTRACTThe effects of chain extension and branching on the properties of nanocomposites produced from recycled poly (ethylene-terephthalate) and organically modified clay were investigated. As the potential chain extension/branching agent, maleic anhydride (MA) and pyromellitic dianhydride (PMDA) were used. The nanocomposites were prepared by twin-screw extrusion, followed by injection molding. Recycled poly (ethylene-terephthalate) was mixed with 2, 3 or 4 weight % of organically modified montmorillonite. During the second extrusion step, 0.5, 0.75 or 1 weight % of MA or PMDA was added to the products of the first extrusion. The effects of the sequence of addition of the ingredients on the final properties of the nanocomposites were also investigated. X-Ray Diffraction analysis showed that, the interlayer spacing of Cloisite 25A expanded from 19.21 Å to about 28–34 Å after processing with polymer indicating an intercalated structure. PMDA content, MA content and screw speed did not have a significant effect on the expanded interlayer distance. In the first extrusion step, nanocomposites containing 3% organoclay content gave significant increase in Young's modulus and decrease in elongation at break values indicating good interfacial adhesion. After the addition of anhydrides, it was observed that, in general PMDA improved the mechanical properties of the nanocomposite owing to the branching and chain extension effects that increase the molecular weight. However, MA did not significantly improve the properties, since in this case the chain scission seemed to be more dominant.

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Plasticized Biodegradable Poly(lactic acid) Based Composites Containing Cellulose in Micro- and Nanosize

Journal of Engineering ◽

10.1155/2013/329379 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 29

Author(s):

Katalin Halász ◽

Levente Csóka

Keyword(s):

Lactic Acid ◽

Microcrystalline Cellulose ◽

Composite Films ◽

Poly Lactic Acid ◽

Twin Screw Extrusion ◽

Scanning Calorimetry ◽

Screw Extrusion ◽

Twin Screw ◽

Biodegradable Poly ◽

Poly Ethylene

The aim of this work was to study the characteristics of thermal processed poly(lactic acid) composites. Poly(ethylene glycol) (PEG400), microcrystalline cellulose (MCC), and ultrasound-treated microcrystalline cellulose (USMCC) were used in 1, 3, and 5 weight percents to modify the attributes of PLA matrix. The composite films were produced by twin screw extrusion followed by film extrusion. The manufactured PLA-based films were characterized by tensile testing, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD), and degradation test.

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Morphology optimization of poly(ethylene terephthalate)/polyamide blends compatibilized via extension-dominated twin-screw extrusion

Journal of Polymer Engineering ◽

10.1515/polyeng-2020-0229 ◽

2021 ◽

Vol 41 (3) ◽

pp. 218-225

Author(s):

Hao Chen ◽

Molin Guo ◽

David Schiraldi ◽

João M. Maia

Keyword(s):

Droplet Size ◽

Ethylene Terephthalate ◽

Aromatic Polyamide ◽

Twin Screw Extrusion ◽

Immiscible Polymers ◽

Poly Ethylene Terephthalate ◽

Screw Extrusion ◽

Twin Screw ◽

Order Of Magnitude ◽

Poly Ethylene

Abstract Poly(ethylene terephthalate) (PET) and polyamide (PA) are immiscible polymers, which requires the use of compatibilizers to stabilize the morphology and achieve acceptable property levels. Therefore, controlling the degree of dispersion, especially the size of the disperse PA droplets in the PET matrix is of paramount importance. This study aims to improve the mixing, i.e., minimize PA droplet size, in immiscible and compatibilized PET/PA and PET/Nylon-MXD6 (MXD6) blends by resorting to extension-dominated mixing in twin-screw extrusion (TSE). MXD6 is an aromatic polyamide similar in polarity to PET, so it is expected that it will blend more effectively than is the case with aliphatic nylon-6 and PET. Two screw configurations are used, a benchmark shear-dominated screw with kneading blocks (KBs) in an aggressive configuration, and an extension-dominated screw configuration with static mixers with hyperbolic C–D channels, recently developed by our group, in place of the KBs. The results show that the use of extensional mixing elements (EMEs) in place of KBs results in a significant decrease of both average and maximum droplet size for all blends, and up to more than one order of magnitude between the most extreme cases of the KB-processed immiscible blend and EME-processed compatibilized blends.

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The Effect of Poly(Butylene Adipate-co-Terephthalate) on Crystallization Behavior and Morphology of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.798.343 ◽

2019 ◽

Vol 798 ◽

pp. 343-350

Author(s):

Sitthi Duangphet ◽

Damian Szegda ◽

Karnik Tarverdi ◽

Jim Song

Keyword(s):

Crystal Structure ◽

Crystallization Behavior ◽

X Ray Diffraction ◽

Twin Screw Extrusion ◽

Scanning Calorimetry ◽

Sem Images ◽

X Ray ◽

Screw Extrusion ◽

Twin Screw ◽

Matrix Morphology

The effects of poly(butylene adipate-co-terephthalate) (PBAT) on crystallization behavior and morphology of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were studied to provide the useful information to control and improve PHBV processing. PHBV were blended with 15, 30 and 50 wt% PBAT by twin screw extrusion and these were subsequently compared to unblended PHBV. The rate of crystal development determined from differential scanning calorimetry (DSC) at 120 °C showed that the incorporation of PBAT retarded the crystal growth rate. Moreover, the crystal structure of polymer blends was examined by X-ray diffraction (XRD) and the results revealed that PBAT did not affect the crystal structure of PHBV. The responses of the melt-crystallized PHBV to different quantities of PBAT were recorded by polarized optical microscopy (POM). The results demonstrated that the size of spherulite dramatically increased when 15 wt% PBAT was added and the shape of spherulite was imperfect when PBAT reached 30 wt%. The morphologies of PHBV and its blends on the freeze-fractured specimens were exposed using scanning electron microscopy (SEM). The SEM images revealed the phase separation of PHBV/ PBAT blends in any composition. The morphology of 15 and 30 wt% PBAT presented droplet in matrix morphology and changed to co-continuous morphology at 50 wt% PBAT.

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Fibrous soy protein meat analog from low moisture twin-screw extrusion

10.32469/10355/6035 ◽

2007 ◽

Author(s):

Suxuan Xu

Keyword(s):

Soy Protein ◽

Twin Screw Extrusion ◽

Screw Extrusion ◽

Twin Screw ◽

Meat Analog

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Enhanced Dispersive Mixing in Twin-Screw Extrusion via Extension-Dominated Static Mixing Elements of Varying Contraction Ratios

International Polymer Processing ◽

10.3139/217.3857 ◽

2020 ◽

Vol 35 (1) ◽

pp. 37-49 ◽

Cited By ~ 7

Author(s):

H. Chen ◽

V. Pandey ◽

S. Carson ◽

J. M. Maia

Keyword(s):

Twin Screw Extrusion ◽

Screw Extrusion ◽

Twin Screw ◽

Dispersive Mixing

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In-Line Rheo-Optical Investigation of the Dispersion of Organoclay in a Polymer Matrix during Twin-Screw Compounding

Polymers ◽

10.3390/polym13132128 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2128

Author(s):

Paulo F. Teixeira ◽

José A. Covas ◽

Loïc Hilliou

Keyword(s):

Local Heating ◽

Polymer Nanocomposite ◽

Structural Rearrangement ◽

Particle Dispersion ◽

Optical Investigation ◽

Twin Screw Extrusion ◽

Clay Particles ◽

Clay Dispersion ◽

Screw Extrusion ◽

Twin Screw

The dispersion mechanisms in a clay-based polymer nanocomposite (CPNC) during twin-screw extrusion are studied by in-situ rheo-optical techniques, which relate the CPNC morphology with its viscosity. This methodology avoids the problems associated with post extrusion structural rearrangement. The polydimethylsiloxane (PDMS) matrix, which can be processed at ambient and low temperatures, is used to bypass any issues associated with thermal degradation. Local heating in the first part of the extruder allows testing of the usefulness of low matrix viscosity to enhance polymer intercalation before applying larger stresses for clay dispersion. The comparison of clay particle sizes measured in line with models for the kinetics of particle dispersion indicates that larger screw speeds promote the break-up of clay particles, whereas smaller screw speeds favor the erosion of the clay tactoids. Thus, different levels of clay dispersion are generated, which do not simply relate to a progressively better PDMS intercalation and higher clay exfoliation as screw speed is increased. Reducing the PDMS viscosity in the first mixing zone of the screw facilitates dispersion at lower screw speeds, but a complex interplay between stresses and residence times at larger screw speeds is observed. More importantly, the results underline that the use of larger stresses is inefficient per se in dispersing clay if sufficient time is not given for PDMS to intercalate the clay galleries and thus facilitate tactoid disruption or erosion.

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