Cellulose crystallinity can be altered by various treatment methods, including mechanical or chemical treatments, which can affect the properties of thermoplastic composites. In this study, the crystallinity of cellulose was manipulated using mechanical ball milling. The primary objective was to assess the impact of altering the cellulose crystallinity on the overall performance of high-density polyethylene (HDPE)-based composites. The mechanical and structural properties of the composites were assessed using tensile and impact tests, attenuated total reflectance infrared ( ATR-IR ) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The degradation properties of the HDPE composites were evaluated using a soil-burial degradation test. The impact of cellulose crystallinity on the mechanical properties of HDPE composites showed a marginal enhancement of 5% in tensile strength with the incorporation of 2% low-crystallinity cellulose (LCC). The highest impact strength of the HDPE composites was attained by the incorporation of 6% LCC. ATR-IR analysis showed that the peak intensity of the HDPE-LCC composite decreased, whereas the HDPE composite with high-crystallinity cellulose (HCC) did not exhibit changes in peak intensity compared to the HDPE spectrum. SEM examination showed that LCC possessed superior dispersion in the HDPE matrix compared to that of HCC. Thermal degradation decreased by up to 32% with the addition of HCC and LCC. A soil burial degradation study showed that the mechanical properties of the HDPE-LCC composite deteriorated more than those of the HDPE-HCC composite after 24 months. This study concluded that altering the crystallinity of cellulose can lead to composites with tailored properties.

This study explores the feasibility and benefits of utilizing plastic waste in the production of construction materials, specifically composite bricks. The escalating accumulation of plastic waste poses significant environmental challenges, which necessitates innovative approaches for recycling and re-utilization to mitigate pollution and reduce landfill use. Our research focuses on the synthesis of bricks by incorporating high-density polyethylene (HDPE) and polystyrene (PS) with sand brick powder, utilizing a compatibilizer (SBS-g-MA) to enhance interfacial adhesion and mechanical integrity. The experimental methodology involved the preparation of composite materials through melt mixing, followed by molding to form brick specimens. These were analyzed for their mechanical properties, including tensile strength, Young's modulus, and elongation at break, as well as thermal properties such as degradation temperature and crystallization behavior. Results showed that the inclusion of sand brick powder significantly enhances the thermal stability of the composites, as evidenced by the higher degradation temperatures observed. Specifically, the degradation temperature increased from 300.59 degrees C in pure HDPE/PS blends to 420.39 degrees C in composites with 7% brick powder, suggesting the formation of a protective barrier against thermal decomposition. Moreover, mechanical testing revealed that composites with up to 7% brick powder exhibited improved tensile strength and Young's modulus compared to pure polymer blends.

The surging quest for asphalt pavement sustainable approaches promotes the need for balancing environmental and economic benefits. With the global production of waste plastics (WP) reaching drastic levels and recycling rates remaining disappointingly low, policymakers are increasingly advocating for the reuse of post -consumer recycled plastics in construction materials. In this study, recycling WP emerges as the most feasible solution, particularly when considering the environmental hazards associated with burning and landfilling, such as air and soil pollution. Recycling WP in asphalt mixture specifically has been quested due to the high -daily production of asphalt mixture, but concerns exist regarding its engineering performance. This study's focus is to assess the asphalt mixture mechanical response while incorporating WP, particularly High -Density Polyethylene (HP), in addition to assessing their environmental impacts. Four asphalt mixtures were rigorously evaluated containing four different asphalt binders: polymer -modified PG 76-22 and PG 70-22, unmodified PG 67-22, and HPmodified PG 67-22 asphalt binders. The investigation encompassed an in-depth analysis of asphalt binder rheological characteristics and asphalt mixtures' mechanical properties. A pivotal aspect of this study was comparing the environmental benefits of HP -modified asphalt binders against conventional polymer -modified ones. This comparison was conducted through a detailed cradle -to -gate life -cycle assessment (LCA). Results indicate that asphalt mixture containing WP material demonstrated similar engineering performance as compared to conventional mixture containing PG 70-22 asphalt binder. Further, the LCA analysis revealed that the inclusion of HP WP in asphalt binders, as compared to PG 76-22 and PG 70-22 asphalt binders, can significantly lower the global warming potential by 17.7% and 8.9%, respectively.

The development of efficient and sustainable composites remains a primary objective of both research and industry. In this study, the use of biochar, an eco-friendly reinforcing material, in additive manufacturing (AM) is investigated. A high-density Polyethylene (HDPE) thermoplastic was used as the matrix, and the material extrusion (MEX) technique was applied for composite production. Biochar was produced from olive tree prunings via conventional pyrolysis at 500 degrees C. Composite samples were created using biochar loadings in the range of 2.0-10.0 wt. %. The 3D-printed samples were mechanically tested in accordance with international standards. Thermogravimetric analysis (TGA) and Raman spectroscopy were used to evaluate the thermal and structural properties of the composites. Scanning electron microscopy was used to examine the fractographic and morphological characteristics of the materials. The electrical/dielectric properties of HDPE/biochar composites were studied over a broad frequency range (10-2 Hz-4 MHz) at room temperature. Overall, a laborious effort with 12 different tests was implemented to fully characterize the developed composites and investigate the correlations between the different qualities. This investigation demonstrated that biochar in the MEX process can be a satisfactory reinforcement agent. Notably, compared to the control samples of pure HDPE, biochar increased the tensile strength by over 20% and flexural strength by 35.9% when added at a loading of 4.0 wt. %. The impact strength and microhardness were also significantly improved. Furthermore, the Direct current (DC) conductivity of insulating HDPE increased by five orders of magnitude at 8.0 wt. % of biochar content, suggesting a percolation threshold. These results highlight the potential of C-based composites for the use in additive manufacturing to further exploit their applicability by providing parts with improved mechanical performance and eco-friendly profiles. The reinforcement of MEX 3D printed parts with eco-friendly biochar. Biochar was obtained from olive trees. Popular high-density polyethylene (HDPE) was the polymeric matrix in the study. biochar increased the tensile strength by over 20% and the flexural strength by 35.9% at a loading of 4 wt. %. The DC conductivity of the insulating HDPE increased by five orders of magnitude at 8 wt. % biochar loading.

Rerounding is a technique for remediating excess deflection in thermoplastic pipe. A pneumatic device vibrates along the vertical axis and pushes against the inside crown and invert to restore the original pipe shape and redistribute the surrounding backfill. A systematic evaluation of the method was justified because rerounding is routinely used by contractors to remediate deflected thermoplastic pipes, and it has not been investigated outside of a few previous reports. Three 900-mm and two 450-mm corrugated high-density polyethylene (HDPE) pipes were installed in various bedding and backfill materials. Test pipes were intentionally installed with substantial deflection (10% or more) and then rerounded. The pipe conditions were measured and monitored by collecting profiles, measuring vertical deflections, and monitoring soil pressure, soil stiffness, backfill characteristics, and pipe corrugation depth before and after rerounding. The data from the deflection, soil stiffness, corrugation, and soil pressure monitoring confirmed the following: (1) during rerounding, soil particles migrated and soil pressure was redistributed; fine material from the crown and springline moved down toward the haunch area, at least in the well-graded aggregate backfill; (2) it is difficult to successfully reduce deflection in corrugated HDPE pipes in well-graded aggregate backfill; (3) installing the pipes with excess deflection proved a significant challenge, as all the pipes required much effort to reach sufficient deflection. It proved necessary to create a device to hold the pipe in a deflected state during backfilling; (4) rerounding successfully reduces deflections for pipes in sand backfill; and (5) test pipes backfilled with Ohio Department of Transportation (ODOT) Type-3 backfill were easy to reround, but a change in environmental conditions and/or dynamic loading may create a change in the stress path leading to excessive deflection and reversal of the effects of rerounding.