Characterization of the Thermal, Structural, and Mechanical Properties of Recycled HDPE

Abstract

High‐density polyethylene (HDPE) is one of the most popular plastics used in industry. Although it replaces many natural resources, due to the low cost and easy processing, its ever‐increasing wastes make it harmful for the environment. Thus, many processes are used in order to recycle it. In the present study, the properties of recycled HDPE (r‐HDPE) compared to virgin HDPE are investigated. The structural studies are performed by X‐ray diffraction (XRD). The thermal properties of virgin HDPE and r‐HDPE are measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Moreover, the mechanical properties are examined by Instron tensile strength experiments. Comparing the results, r‐HDPE does not show any significant differences regarding its structural and thermal properties. Additionally, it is found that r‐HDPE has a slight increase in tensile strength. As a result, considering that the mechanical process to produce r‐HDPE does not affect its general properties, it is suitable for further processing.

The use of recycled high‐density polyethylene waste to manufacture eco‐friendly plastic sand bricks

“…Two main endothermic peaks were identified at 135 and 485°C due to the plastic melting and burning. These observations were similar to the studies conducted by Chrysafi et al 54 and Sustaita‐Rodríguez et al 55 …”

“…Two main endothermic peaks were identified at 135 and 485 C due to the plastic melting and burning. These observations were similar to the studies conducted by Chrysafi et al 54 and Sustaita-Rodríguez et al 55 Figure 4 shows the thermal profile of the river sand which was conducted at 1000 C. A small percentage (0.16%) mass of river sand was lost between 0 C and approximately 125 C as a result of water evaporation. The greatest loss of weight in the river sand of 0.31% was recorded in the temperature range of 230-660 C and a clear multistage decomposition process was noted.…”

Evaluation of Eco-Friendly Hemp-Fiber-Reinforced Recycled HDPE Composites

“…It extends between the temperature range of 250 and 310 • C and is due to the decomposition of hemicellulose. The second stage extends up to 415 • C and is due to the decomposition of cellulose, while the percentage of mass that decomposes increases with the increase in the percentage of hemp [6]. In the main stage of degradation up to 600 • C, the complete decomposition of r-HDPE and a percentage of lignin is observed, while the mass that remains and increases with the increase in its percentage is due to a small percentage of lignin that is not completely decomposed and other minerals.…”

“…This problem was severely intensified during the COVID-19 pandemic, when tons of single-use polymeric materials, such as gloves and masks, were used on a daily basis [4,5]. Within this frame, European Union has established a policy to promote circular economy with the recycling of common petroleum-sourced polymers, such as high-density polyethylene (HDPE) [6] and poly(ethylene terephthalate) (PET) [7,8]. Furthermore, researchers are developing new technologies and processes to enhance their recycling and upcycling efficiency, such as thermomechanical processing, chemical recycling (glycolysis and pyrolysis), and biological depolymerization using enzymes and microorganisms [9,10].…”

Influence of Adding Polypropylene(pp) Into Polyethylene(pe) on Mechanical Properties of Geocells

“…The main disadvantages of polyethylene are the weak resistance to light and heat, but due to the specifics of its application, geocells are not exposed to direct light and high temperatures, which also predisposes to its use. From an economic point of view, there are also prerequisites for its use, because on one hand, primary polyethylene has a low cost and is widely available, and also the fact that Highdensity polyethylene (HDPE) is one of the most popular plastics used in industry [11], [12].…”