scholarly journals Polymeric Nanocomposites: Compounding and Performance

2008 ◽  
Vol 8 (4) ◽  
pp. 1582-1596 ◽  
Author(s):  
L. A. Utracki
Keyword(s):  
Mechanical Performance ◽  
Extensional Flow ◽  
Polyamide 6 ◽  
Nano Particles ◽  
Polymeric Nanocomposites ◽  
Organic Salts ◽  
Melt Compounding ◽  
Twin Screw ◽  
And Performance ◽  
Kinetics Of

Polymeric nanocomposites (PNC) are binary mixtures of strongly interacting, inorganic platelets dispersed in a polymeric matrix. For full exfoliation, the thermodynamic miscibility is required. There are three basic methods of organically-modified clay dispersion that might result in PNC: (1) in polymer solution (followed by solvent removal), (2) in a monomer (followed by polymerization), and (3) in molten polymer (compounding). Most commercial PNC are produced by the second method, but it is the third one that has the greatest promise for the plastics industry. Similarly as during the manufacture of polymer blends, the layered silicates must be compatibilized by intercalation with organic salts and/or addition of functionalized macromolecules. Compounding affects the kinetics of dispersion process, but rarely the miscibility. Melt compounding is carried out either in a single-screw (SSE) or a twin-screw extruder (TSE). Furthermore, an extensional flow mixer (EFM) might be attached to an extruder. Two versions of EFM were evaluated: (1) designed for polymer homogenization and blending, and (2) designed for dispersing nano-particles. In this review, the dispersion of organoclay in polystyrene (PS), polyamide-6 (PA-6) or in polypropylene (PP) is discussed. The PNC based on PS or PA-6 contained two components (polymer and organoclay), whereas those based on PP in addition had a compatibilizer mixture of two maleated polypropylenes. Better dispersion was found compounding PNC's in a SSE + EFM than in TSE with or without EFM. The mechanical performance (tensile, flexural and impact) was examined.

scholarly journals Rheological characterization of polymer-based nanocomposites with different nanoscale dispersions

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Dong Gi Seong ◽  
Tae Jin Kang ◽  
Jae Ryoun Youn
Keyword(s):  
Storage Modulus ◽  
Extensional Flow ◽  
Rheological Behaviour ◽  
Polyamide 6 ◽  
Twin Screw Extrusion ◽  
Rheological Characterization ◽  
Melt Compounding ◽  
Transmission Electron ◽  
Screw Extrusion ◽  
Twin Screw

AbstractPolyamide 6 - clay nanocomposites with different nanoscale dispersions were prepared by melt compounding via twin-screw extrusion and their internal structures were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The rheological behaviour of these nanocomposites in shear and extensional flow were investigated using an Advanced Rheometric Expansion System and an Elongational Melts Rheometer in connection with the analysis by XRD and TEM. Nanocomposites with fully exfoliated structure and with poorly dispersed structure showed very different rheological behaviour. In general, addition of clay increased the viscosity and the storage modulus of nanocomposites, but different rheological behaviours were observed depending upon the degree of clay dispersion in the polymer matrix. In shear flow, only the exfoliated nanocomposite showed solid-like plateau behaviour in storage modulus and strong shear-thinning behaviour in shear viscosity. In extensional flow, only fully exfoliated nanocomposites showed strain-hardening behaviour, which is caused by the interaction between nanoparticles as well as between polymer molecules and nanoparticles.

Preparation and Chracterization of Nanocomposites of Polyamide 6/Brazilian Clay with Different Organic Modifiers

2008 ◽  
Vol 570 ◽  
pp. 18-23 ◽  
Author(s):  
Michelle A. Souza ◽  
Nelson M. Larocca ◽  
Edcleide Maria Araújo ◽  
Luiz Antonio Pessan
Keyword(s):  
Bentonite Clay ◽  
Polyamide 6 ◽  
X Rays ◽  
Organic Modifiers ◽  
Screw Extruder ◽  
Organic Salts ◽  
Transmission Electron ◽  
Twin Screw ◽  
Izod Impact ◽  
Injection Molded

Nanocomposites of PA6 / organoclay at different concentration were prepared via melt intercalation method using a corotating twin screw extruder. The composites were prepared with Brazilian clay that was treated with different modifiers based on quaternary ammonium salts to obtain three types of organoclays. After extrusion the mixtures were injection molded into specimens that were tested to obtain the properties of tensile strength, notched izod impact and heat deflection temperature. The structure and morphology of the nanocomposites were characterized by x-rays diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the modifier “dodigen” which promoted the intermediate expansion of the bentonite clay within the three salts used for the modification of the clay affects more significantly the mechanical properties, HDT and morphology of the polyamide 6 due to the higher level of exfoliation observed in these systems compared to the others modifiers. The improvement of the properties was correlated to the level of exfoliation/intercalation obtained which depends on the process technique used, surface treatment of the Brazilian clays with organic salts and interaction between polymer and clay.

The Non-Isothermal Crystallization Kinetics of Dispersible Nano-SiO2/PA66 Composites

2012 ◽  
Vol 535-537 ◽  
pp. 94-102
Author(s):  
Lei Jia ◽  
Li Ping Guo ◽  
Xiang Min Xu
Keyword(s):  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Activation Energies ◽  
Crystallization Time ◽  
Dsc Analysis ◽  
Screw Extruder ◽  
Isothermal Crystallization Kinetics ◽  
Melt Compounding ◽  
Twin Screw ◽  
Kinetics Of

The PA66-based composites containing dispersible nano-SiO2 (DNS) were prepared in a twin-screw extruder by melt compounding. The microstructures of dispersible nano-SiO2/PA66 composites were investigated by means of TEM and XRD, and the non-isothermal crystallization behavior was studied through Jeziorny method and Mo method based on DSC analysis. The results showed that the dispersion of DNS was uniform in PA66 matrix, which could be related to surface structure of dispersible nano-SiO2. It was found from the study of the non-isothermal crystallization kinetics that dispersible nano-SiO2 possessed a heterogeneous nucleation capability in PA66 matrix, and its addition could hinder the motion of PA66 molecular chain, lower the crystallization temperature, and prolong the crystallization time of PA66. In addition, the activation energies for non-isothermal crystallization of neat PA66 and composites were also evaluated by the Kissinger method. The result showed that the activation energies of dispersible nano-SiO2/PA66 composites were higher than that of neat PA66.

The Effects of Melt Compounding Method on the Ambient and In Vitro Mechanical Properties of EVA/MMT Nanocomposites

2015 ◽  
Vol 789-790 ◽  
pp. 75-79 ◽  
Author(s):  
Azlin Fazlina Osman ◽  
Tew Wei Hong ◽  
Abdulkader M. Alakrach
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Melt Compounding ◽  
Twin Screw ◽  
Internal Mixer ◽  
Nanofiller Content ◽  
Eva Copolymer

The in vitro biostability of ethyl vinyl acetate (EVA) nanocomposite incorporating the organically modified montmorillonite (organo-MMT) was investgated as a new material for biomedical applications. The effects of compounding process and filler loadings on the ambient and in vitro (exposed in oxidizing condition, 37°C) mechanical properties were studied. We have observed that, the melt compounded EVA copolymer by internal mixer (Brabender plasticoder) achieved the highest ambient and in vitro mechanical properties at low nanofiller content (1wt% organo-MMT). In contrast, the melt compounded EVA copolymer by twin screw extruder achieved the highest ambient and in vitro mechanical properties at high nanofiller content (5wt% organo-MMT). We suggest that this was due to the capability of the twin screw extruder to provide greater shear force for the exfoliation and dispersion of the high content organo-MMT as compared to internal mixer (Brabender plasticoder). However, compounding by twin screw extruder caused more severe reduction in tensile toughness of the EVA containing 5 wt% organo-MMT, after this material was exposed to oxidative agent, 37°C. These studies show that the melt compounding method may bring significant effect to both the ambient and in vitro mechanical performance of the EVA nanocomposites, and hence further investigation towards optimization should be pursued.

scholarly journals Effects of a Twin-Screw Extruder Equipped with a Molten Resin Reservoir on the Mechanical Properties and Microstructure of Recycled Waste Plastic Polyethylene Pellet Moldings

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1058
Author(s):  
Hikaru Okubo ◽  
Haruka Kaneyasu ◽  
Tetsuya Kimura ◽  
Patchiya Phanthong ◽  
Shigeru Yao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Value Added ◽  
Industrial Applications ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Polymer Properties ◽  
Wide Range ◽  
Twin Screw ◽  
Recycled Plastics

Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young’s modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.

scholarly journals Use of Treated Non-Ferrous Metallurgical Slags as Supplementary Cementitious Materials in Cementitious Mixtures

2021 ◽  
Vol 11 (9) ◽  
pp. 4028
Author(s):  
Asghar Gholizadeh Vayghan ◽  
Liesbeth Horckmans ◽  
Ruben Snellings ◽  
Arne Peys ◽  
Priscilla Teck ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Strength Development ◽  
Supplementary Cementitious Material ◽  
Performance Requirements ◽  
Metallurgical Slags ◽  
Leaching Behaviour ◽  
Kinetics Of

This research investigated the possibility of using metallurgical slags from the copper and lead industries as partial replacement for cement. The studied slags were fayalitic, having a mainly ferro-silicate composition with minor contents of Al2O3 and CaO. The slags were treated at 1200–1300 °C (to reduce the heavy metal content) and then granulated in water to promote the formation of reactive phases. A full hydration study was carried out to assess the kinetics of reactions, the phases formed during hydration, the reactivity of the slags and their strength activity as supplementary cementitious material (SCM). The batch-leaching behaviour of cementitious mixtures incorporating treated slags was also investigated. The results showed that all three slags have satisfactory leaching behaviour and similar performance in terms of reactivity and contribution to the strength development. All slags were found to have mediocre reactivity and contribution to strength, especially at early ages. Nonetheless, they passed the minimum mechanical performance requirements and were found to qualify for use in cement.

scholarly journals Thermal and Quasi-Static Mechanical Characterization of Polyamide 6-Graphene Nanoplatelets Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1454
Author(s):  
Pietro Russo ◽  
Francesca Cimino ◽  
Antonio Tufano ◽  
Francesco Fabbrocino
Keyword(s):  
Chemical Resistance ◽  
Experimental Tests ◽  
Polyamide 6 ◽  
Graphene Nanoplatelets ◽  
Strength Parameter ◽  
Melt Compounding ◽  
Static Mechanical ◽  
Thermal And Electrical Properties ◽  
Multifunctional Products

The growing demand for lightweight and multifunctional products in numerous industrial fields has recently fuelled a growing interest in the development of materials based on polymer matrices including graphene-like particles, intrinsically characterized by outstanding mechanical, thermal, and electrical properties. Specifically, with regard to one of the main mass sectors, which is the automotive, there has been a significant increase in the use of reinforced polyamides for underhood applications and fuel systems thanks to their thermal and chemical resistance. In this frame, polyamide 6 (PA6) composites filled with graphene nanoplatelets (GNPs) were obtained by melt-compounding and compared in terms of thermal and mechanical properties with the neat matrix processed under the same condition. The results of the experimental tests have shown that the formulations studied so far offer slight improvements in terms of thermal stability but much more appreciable benefits regarding both tensile and flexural parameters with respect to the reference material. Among these effects, the influence of the filler content on the strength parameter is noteworthy. However, the predictable worsening of the graphene sheet dispersion for GNPs contents greater than 3%, as witnessed by scanning electron images of the tensile fractured sections of specimens, affected the ultimate performance of the more concentrated formulation.

scholarly journals Preparation and Performance Evaluation of Duotone 3D-Printed Polyetheretherketone as Oral Prosthetic Materials: A Proof-of-Concept Study

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1949
Author(s):  
Ling Ding ◽  
Wei Lu ◽  
Jiaqi Zhang ◽  
Chuncheng Yang ◽  
Guofeng Wu
Keyword(s):  
Titanium Dioxide ◽  
Performance Evaluation ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Flexural Properties ◽  
Proof Of Concept ◽  
Tooth Color ◽  
Dental Application ◽  
3D Printed ◽  
And Performance

Literature has reported the successful use of 3D printed polyetheretherketone (PEEK) to fabricate human body implants and oral prostheses. However, the current 3D printed PEEK (brown color) cannot mimic the vivid color of oral tissues and thus cannot meet the esthetical need for dental application. Therefore, titanium dioxide (TiO2) and ferric oxide (Fe2O3) were incorporated into PEEK to prepare a series of tooth-color and gingival-color PEEK composites in this study. Through color measurements and mechanical tests, the color value and mechanical performance of the 3D printed PEEK composites were evaluated. In addition, duotone PEEK specimens were printed by a double nozzle with an interface between tooth-color and gingival-color parts. The mechanical performance of duotone PEEK with two different interfaces (horizontal and vertical) was investigated. With the addition of TiO2 and Fe2O3, the colors of 3D printed PEEK composites become closer to that of dental shade guides. 3D printed PEEK composites generally demonstrated superior tensile and flexural properties and hence have great potential in the dental application. In addition, duotone 3D printed PEEK with a horizontal interfacial orientation presented better mechanical performance than that with a vertical one.

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