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 Restoring mechanism of mechanical properties of recycled polyethylene pellet moldings by a repelletizing treatment using a twin-screw extruder

2021 ◽  
Vol 23 (3) ◽  
pp. 1152-1176
Author(s):  
H. Okubo ◽  
S. Yao
Keyword(s):  
Mechanical Properties ◽  
Value Added ◽  
Polymer Materials ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Material Recycling ◽  
Tensile Performance ◽  
Recycled Polyethylene ◽  
Twin Screw ◽  
Plastic Products

AbstractTo develop material-recycling processes for used plastic products, it is necessary to design new material-recycling techniques to optimize the mechanical properties of the recycled plastics since the mechanical properties of recycled plastic products are normally deteriorated. In this study, we suggest one of the approaches that is a repelletizing treatment for improving the mechanical properties of recycled-polyethylene moldings using a twin-screw extruder. The results of the tensile test revealed the significant effect of the repelletizing treatment on the tensile performance of the recycled-polyethylene moldings. The tensile performance of the repelletized recycled-polyethylene moldings was significantly higher than that of the original recycled-polyethylene moldings under specific repelletizing conditions. The analysis of the polymeric structures revealed the significant effect of the repelletizing treatment on the secondary and higher-order structures such as the lamellar shape, aggregation of the crystal domains, amorphousness, and polyethylene chain conformation in the recycled-polyethylene moldings. The repelletizing treatment increased the tensile performances by optimizing the internal structure of the recycled-polyethylene moldings. The results confirmed the efficacy of the repelletizing treatment to optimize the mechanical performance of the recycled-polymer materials, thereby facilitating the reuse of waste plastics as value-added materials for various industrial applications.

Co-Continuous PPS/PA66 Composites - Part II: Mechanical Performance

2013 ◽  
Vol 804 ◽  
pp. 102-105
Author(s):  
Tao Yin ◽  
Yu Qi Gu ◽  
Chun Yu Yu ◽  
Zi Xin Li
Keyword(s):  
Mechanical Properties ◽  
Phase Structure ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Continuous Phase ◽  
Polyamide 66 ◽  
Screw Extruder ◽  
Wide Range ◽  
Twin Screw

Poly (phenylene sulfide) (PPS) was blended with polyamide 66 (PA66) in a wide range of compositions by using a co-rotating twin-screw extruder. Dynamic mechanical analysis was used in determination of the co-continuous phase. The results allowed to precisely detecting the range of co-continuity. In addition, the mechanical properties of PPS/PA66 composites can also be used to identify the dispersed/matrix phase or co-continuous phase structure.

scholarly journals Transparent PC/PMMA Blends Via Reactive Compatibilization in a Twin-Screw Extruder

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2070 ◽  
Author(s):  
Tobias Bubmann ◽  
Andreas Seidel ◽  
Volker Altstädt
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Side Effect ◽  
Extrusion Process ◽  
Industrial Applications ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Reactive Compatibilization ◽  
Twin Screw ◽  
Pmma Blends

The effect of different catalysts on reactive compatibilization of 50/50 polycarbonate (PC)/polymethylmethacrylate (PMMA) blends achieved via transesterification that occurs during compounding in a twin-screw extruder was investigated on a phenomenological (optical and mechanical properties), mesoscopic (phase morphology), and molecular level (PC-graft(g)-PMMA-copolymer formation and polymer molecular weight degradation). Formation of PC-(g)-PMMA-copolymer by transesterification resulting in transparent mono-phase PC/PMMA blends with obviously improved compatibility of the two polymer constituents requires use of a suitable catalyst. As a side-effect, PC-(g)-PMMA-copolymer formation by transesterification is always accompanied by a significant simultaneous decomposition of the molecular weight (Mw) of the PC. For the first time, a colorless, transparent (mono-phase) PC/PMMA 50/50 blend was achieved by a twin-screw extrusion process that can be easily transferred into industrial scale. To achieve this milestone, 0.05 wt% of a weakly acidic phosphonium salt catalyst had to be applied. As a result of the decrease in Mw of the PC, the mechanical properties (e.g., tensile strain at break and impact strength) of the obtained blends were significantly deteriorated rather than improved as targeted by the polymer compatibilization; therefore, the produced transparent PC/PMMA blends are considered not yet technically suitable for any industrial applications. Different manufacturing process strategies that do not inherently result in PC degradation as a side effect of PC-graft(g)-PMMA-copolymer formation have to be developed to potentially achieve transparent PC/PMMA blends with a useful balance of properties. Based on the experimental observations of this study, a new mechanism of the transesterification reaction occurring during reactive compounding of PC and PMMA in the presence of the effective catalysts is proposed.

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 Thermo-Mechanical Behaviour of the Raffinate Resulting from the Aqueous Extraction of Sunflower whole Plant in Twin-Screw Extruder: Manufacturing of Biodegradable Agromaterials by Thermo-Pressing

2010 ◽  
Vol 112 ◽  
pp. 63-72 ◽  
Author(s):  
Philippe Evon ◽  
Virginie VanDenBossche ◽  
Pierre-Yves Pontalier ◽  
Luc RIGAL
Keyword(s):  
Glass Transition ◽  
Dry Matter ◽  
Milled Powder ◽  
Value Added ◽  
Aqueous Extraction ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Dsc Measurements ◽  
Whole Plant ◽  
Twin Screw

Biorefinery of sunflower whole plant can be realized using a twin-screw extruder. Thermo-mechanical fractionation and aqueous extraction are conducted simultaneously. A filter section is outfitted along the barrel to collect continuously an extract and a raffinate (cake meal). Oil yield obtained is 53%. Proteins are partly extracted at the same time, just as pectins and hemicelluloses. Protein yield is 46%. Cake meal is relatively moist (66% for the moisture content). It is first dried to make easier its conservation. It is largely composed of lignocellulosic fibres (59% of the dry matter) from depithed stalk. Lipid content is 13% of the dry matter or 35% of the oil in whole plant. Protein content is 7% of the dry matter or 45% of the proteins in whole plant. DSC measurements indicate that denaturation of proteins is almost complete in the cake meal. DMTA spectrum of its milled powder reveals a significant peak at high temperature (between 175 and 200°C). As already observed with industrial sunflower cake meal, it can be associated with the glass transition of proteins. As a mixture of fibres and proteins, the cake meal can be considered as a natural composite. It is successfully processed into biodegradable and value-added agromaterials by thermo-pressing. As for DMTA analysis, the glass transition of proteins in the cake meal is also observed with PVT analysis at around 180°C. It makes easier the choice of the best thermo-pressing conditions to produce panels with higher mechanical properties in bending. These properties increase simultaneously with temperature, pressure and time chosen for molding operation. The highest flexural strength at break (11.5 MPa) and the highest elastic modulus (2.22 GPa) are obtained for the next molding conditions: 200°C and 320 kgf/cm2 during 60 s. Drop angle measurements show that the corresponding panel is also the most resistant to water. No significant transition is observed inside this panel above 0°C and until 200°C with DMTA analysis. Proteins ensure the agromaterial cohesion without any phase change in this temperature range, and fibres entanglement also acts like reinforcement. This panel could be used as inter-layer sheets for pallets or for the manufacturing of biodegradable containers (composters, crates for vegetable gardening) by assembly of panels.

Study of a novel co-rotating non-twin screw extruder in processing flame retardant polymer materials

2017 ◽  
Vol 37 (8) ◽  
pp. 827-835
Author(s):  
Song Zhao ◽  
Baiping Xu ◽  
Liang He ◽  
Huiwen Yu ◽  
Shouzai Tan
Keyword(s):  
Flame Retardant ◽  
Mechanical Performance ◽  
Acrylonitrile Butadiene Styrene ◽  
Operating Conditions ◽  
Polymer Materials ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Limiting Oxygen Index ◽  
Twin Screw ◽  
Halogen Free

Abstract A thorough study was carried out to investigate the priority of a novel co-rotating non-twin screw extruder (NTSE) over a traditional twin screw extruder (TSE) in the mixing process of halogen-free intumescent flame-retardant acrylonitrile-butadiene-styrene (ABS) composites. The homogeneity of the flame-retardant additives of the composites processed by NTSE and TSE under the same operating conditions was characterized by using mechanical performance properties, limiting oxygen index values, UL-94 tests, and thermogravimetric analysis. All the results suggested that NTSE could achieve better mixing of the flame-retardant additives in the polymer matrix than TSE, which was further clarified by the scanning electron microscope pictures.

Mechanical Properties of Poly(Butylene Succinate) Reinforced with Alpha Cellulose

2015 ◽  
Vol 1119 ◽  
pp. 283-287
Author(s):  
Sarit Liprapan ◽  
Thumnoon Nhujak ◽  
Pranut Potiyaraj
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Young’S Modulus ◽  
Glycidyl Methacrylate ◽  
Interfacial Interaction ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Butylene Succinate ◽  
Twin Screw

The objective of this study is to prepare α-cellulose reinforced poly (butylene succinate) composites (PBS/α-cellulose). The effect of amount α-cellulose on the mechanical properties of the composites was investigated. To improve interfacial interaction between PBS and α-cellulose, glycidyl methacrylate grafted poly (butylene succinate) (PBS-g-GMA) was used as a compatibilizer. Mechanical properties of PBS composites prepared by using a twin-screw extruder were investigated. The mechanical properties of PBS/α-cellulose decreased due to the agglomeration of α-cellulose. Nevertheless, tensile strength, Young’s modulus and flexural strength of PBS composites were improved after the incorporation of PBS-g-GMA. The optimum loading of PBS-g-GMA and α-cellulose in the PBS was found to be 5 and 6 phr.

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