Hybrid Chemo‐Mechanical Plastics Recycling:  Solvent‐free, High‐speed Reactive Extrusion of Low‐Density Polyethylene

ChemSusChem ◽  
2021 ◽  
Author(s):  
Shawn Martey ◽  
Bennett Addison ◽  
A. Nolan Wilson ◽  
Bin Tan ◽  
Jianger Yu ◽  
...  
Keyword(s):  
High Speed ◽  
Reactive Extrusion ◽  
Solvent Free ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Plastics Recycling

scholarly journals Rendering Bio-Inert Low Density Polyethylene Amenable For Biodegradation Via Fast High Throughput Reactive Extrusion Assisted Oxidation

2021 ◽  
Author(s):  
Pablo Ferrero ◽  
Olivia A. Attallah ◽  
Miguel Ángel Valera ◽  
Ivana Aleksic ◽  
Muhammad Azeem ◽  
...  
Keyword(s):  
High Throughput ◽  
Operating Temperature ◽  
Crystallinity Index ◽  
Reactive Extrusion ◽  
Bacterial Attachment ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Carbonyl Index ◽  
Pre Treatment ◽  
Pretreatment Conditions

Abstract An energy efficient high throughput pre-treatment of low density polyethylene (LDPE) using a fast reactive extrusion (REX) assisted oxidation technique followed by bacterial attachment as an indicator for bio-amenability was studied. Silicon dioxide (SiO2) was selected as a model oxidizing and catalytic reagent with the REX process demonstrated to be effective both in the presence and absence of the catalyst. Optimized 5-minute duration pretreatment conditions were determined using Box-Behnken design (BBD) with respect to screws speed, operating temperature, and concentration of SiO2. The crystallinity index, carbonyl index and weight loss (%) of LDPE were used as the studied responses for BDD. FTIR and DSC spectra of the residual LDPE obtained after pretreatment with the REX assisted oxidation technique showed a significant increase in residual LDPE carbonyl index from 0 to 1.04 and a decrease of LDPE crystallinity index from 29% to 18%. Up to 5-fold molecular weight reductions were also demonstrated using GPC. Optimum LDPE pretreatment with a duration of 5 minutes was obtained at low screw speed (50 rpm), operating temperature of 380-390⁰C and variable concentration of SiO2 (0 and 2% (w/w)) indicating that effective pretreatment can occur under noncatalytic and catalysed conditions. Biofilms were successfully formed on pretreated LDPE samples after 14 days of incubation.Furthermore, the technique proposed in this study is expected to provide a high throughput approach for pretreatment of pervasive recalcitrant PE based plastics to reduce their bio inertness.

Biodegradation study of bio-corn flour filled low density polyethylene composites assessed by natural soil

2016 ◽  
Vol 36 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Samira Sahi ◽  
Hocine Djidjelli ◽  
Amar Boukerrou
Keyword(s):  
Filler Content ◽  
Alkali Treatment ◽  
Reactive Extrusion ◽  
Low Density Polyethylene ◽  
Natural Soil ◽  
Low Density ◽  
Corn Flour ◽  
Scanning Calorimetry ◽  
Soil Burial ◽  
Morphological Studies

Abstract This paper illustrates the aim to introduce biodegradable vegetable filler in synthetic polymers to prepare novel biodegradable composites. Low density polyethylene/alkali treated corn flour (LDPE/ATCF) composites were prepared by reactive extrusion using a twin-screw extruder. The microstructure, thermal properties and tensile properties were evaluated and compared with virgin LDPE. The Fourier transform infrared (FTIR) spectra showed a decrease in the hydrophilic nature of corn flour (CF) after alkali treatment. Scanning electron microscopy (SEM) micrographs showed good dispersion between matrix and filler. The tensile and elongation at break decreased by increasing the filler content in the composites. However, the Young’s modulus increased with the increase in filler content. The biodegradation of composites was studied in the environment using the soil burial test for 6 months. Differential scanning calorimetry (DSC) analysis showed an increase of the melting enthalpy (ΔHm) and crystallinity of LDPE with evidence of degradation. The biodegradability of the composites was enhanced with increasing ATCF content in the matrix. This result was supported by weight loss and degraded surface of composites observed through morphological studies. From the results, we conclude that the use of ATCF as filler in LDPE reduces pollution problems. This is advantageous for both the economy and the environment.

Influence of compatibilizer on the properties of low-density polyethylene/polyamide 6 blends obtained by mechanical recycling of multilayer film waste

2018 ◽  
Vol 36 (8) ◽  
pp. 729-736 ◽  
Author(s):  
Diego David Pinzón Moreno ◽  
Clodoaldo Saron
Keyword(s):  
Reactive Extrusion ◽  
Tensile Tests ◽  
Polyamide 6 ◽  
Multilayer Films ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Mechanical Recycling ◽  
Melt Flow Rate ◽  
Typical Material ◽  
Polymeric Wastes

Polymeric wastes have caused increasing environmental problems, mainly in oceans that accumulate large amounts of non-degradable plastic waste. Particularly, waste of polymeric multilayer films for packaging presents low interest for mechanical recycling due to the poor properties and low commercial value of the recycled material generated as polymeric blends. Multilayer films of low-density polyethylene (LDPE) and polyamide 6 (PA6) is a typical material used for packaging applications. The aim of this study was to evaluate the action of the concentration of maleic anhydride grafted polyethylene (PE- g-MA) on the compatibilization of LDPE/PA6 blends generated from mechanical recycling of multilayer films containing both polymers. The action of the PE- g-MA on the properties of the LDPE/PA6 blends was evaluated by tensile tests, optical microscopy, melt flow rate, and scanning electron microscopy. The use of PE- g-MA at 2.5 wt% as a compatibilizer during reactive extrusion of the multilayer films waste has showed the best result for production of the respective recycled LDPE/PA6 blends.

The effect of the geometry of extrusion head flow channels on the adiabatic extrusion of low density polyethylene

2015 ◽  
Vol 35 (6) ◽  
pp. 605-610 ◽  
Author(s):  
Janusz W. Sikora ◽  
Tomasz Garbacz
Keyword(s):  
High Speed ◽  
Thermal Power ◽  
Circular Cross Section ◽  
Energy Conditions ◽  
Low Density Polyethylene ◽  
Total Power ◽  
Low Density ◽  
Extrusion Head ◽  
Flow Channels ◽  
Very High

Abstract Plastics extrusion can be divided into the following types: conventional extrusion (run at low speed of the rotating screw), adiabatic extrusion (screw speed is relatively high, yet the process requires the use of heaters) and high speed extrusion (extruder barrel requires cooling due to very high screw speeds). This paper presents the results of a study undertaken to investigate the adiabatic extrusion of low density polyethylene using heads with circular cross-section nozzles and different geometries of flow channels. In the experiments, we examined the temperature and pressure of the polymer in the plasticizing unit, as well as the relationships between the output, thermal power conveyed by the plastic, total power supplied to the extruder, extrusion efficiency, unit consumption of the total energy supplied to the extruder as well as the rotational speed of the screw and the extruder’s head geometry. It was found that the most favorable energy conditions, i.e., the highest efficiency of the adiabatic extrusion of low density polyethylene in the whole range of the tested screw speeds, are ensured when the head with the highest diameter and length nozzle is applied.

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