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.

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 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.

Application of a New Twin-Screw Extruder to the Waste Tire Regeneration

2013 ◽  
Vol 561 ◽  
pp. 326-330
Author(s):  
Lei Guo ◽  
Qing Kun Liu ◽  
Chuan Sheng Wang
Keyword(s):  
Mechanical Properties ◽  
Reaction Temperature ◽  
Physical And Mechanical Properties ◽  
Crumb Rubber ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Screw Speed ◽  
Waste Tire ◽  
Twin Screw ◽  
Regeneration Effect

This paper uses a new twin-screw extruder for regeneration of waste tire crumb rubber, discusses the influence of screw speed and reaction temperature on the physical and mechanical properties of reclaimed rubber. Experimental results show that different screw speed and reaction temperature has a great impact on the physical and mechanical properties of the reclaimed rubber. When controls screw speed in the 60 ~ 90 r / min, reaction temperature at 170 to 210°C,the regeneration effect is the best. At this time, the physical and mechanical properties of reclaimed rubber, such as tensile strength, tear strength and elongation at break rate, is the best.

scholarly journals Investigation of the Orientational Mechanical Properties of Biodegradable Extrusion Films Based on Polyolefins and Beet Pulp

2022 ◽  
Author(s):  
A.M. Kuzmin
Keyword(s):  
Mechanical Properties ◽  
Polymer Melt ◽  
Twin Screw Extruder ◽  
Biodegradable Films ◽  
Screw Extruder ◽  
Film Extrusion ◽  
Biodegradable Composites ◽  
Twin Screw ◽  
Beet Pulp ◽  
Extrusion Method

Abstract. The article discusses the possibility of obtaining biodegradable films based on polyolefins and beet pulp by the extrusion method. Biodegradable composites of two mixes with 15% and 25% beet pulp content have been obtained. Compounding was carried out on a twin-screw extruder, and then samples of biodegradable films were obtained by cast film extrusion. The influence of the vegetable filler particles’ orientation on the composites mechanical properties has been studied. It has been shown that composites mechanical properties significantly increase in the direction of polymer melt stretching.

scholarly journals Properties of Poly(Lactic Acid) Filled with Hydrophobic Cellulose/SiO2 Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Kittithorn Lertphirun ◽  
Kawee Srikulkit
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw ◽  
Hydrolysis Of Cellulose ◽  
One Step ◽  
Hydrolysis Of

Hydrophobic cellulose/SiO2 composites were prepared. Resultant hydrophobic cellulose/SiO2 composites were melt mixed with PLA using a twin-screw extruder to obtain 10 wt% masterbatch. Again, 10 wt% masterbatch was melt mixed with virgin PLA, resulting in PLA containing hydrophobic cellulose/SiO2 at various contents (1 wt%, 3 wt%, and 5 wt%) using a twin-screw extruder (barrel zone temperature: 150/160/170/180/190°C (die zone)). Injection-molded samples were prepared for mechanical properties evaluation. Results showed that poor mechanical properties found at low percent loadings were associated with a significant depolymerization of masterbatch composition due to twice thermal treatments. Note that 10 wt% masterbatch was subjected to injection molding straight away in a one-step process. Results showed that 10 wt% hydrophobic cellulose/SiO2/PLA composites exhibited mechanical properties equivalent to neat PLA. Importantly, the addition of hydrophobic cellulose/SiO2 at high percent loading could favor landfill degradation of PLA via water absorption ability of cellulose. It was expected that enzymatic hydrolysis of cellulose resulted in the formation of lactic acid and silicic acid which consequently catalyzed the hydrolytic degradation (acid hydrolysis) of PLA. The hydrolytic degradation produced carboxylic acid end group which further accelerated the degradation rate.

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