Material Development and Properties of Medium-Density Board from Low and High-Density Polyethylene

This research is aimed at investigating the mechanical behavior of the bitumen by the addition of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) obtained from waste plastic bottles and bags. Polymers (HDPE and LDPE) with percentages of 0%, 2%, 4%, and 6% in shredded form by weight of bitumen were used to evaluate the spectroscopic, structural, morphological, and rheological properties of polymer-modified binders. The rheological properties for different factors; viscosity (ἠ) from Rotational Viscometer (RV), rutting factor G*/Sin (δ), fatigue characteristics G*. Sin (δ), for the modified binder from dynamic shear rheometer (DSR), Short and long-term aging from rolling thin film oven (RTFO), and pressure aging vessel (PAV) was determined. The thermal characteristics, grain size, and texture of polymers for both LDPE and HDPE were found using bending beam rheometer (BBR) and X-ray diffraction (XRD), respectively. Fourier transform infrared (FTIR) analysis revealed the presence of polymer contents in the modified binder. Scanning electron microscopy (SEM) images revealed the presence of HDPE and LDPE particles on the surface of the binder. Creep Rate (m) and Stiffness (S) analysis in relationship with temperature showed a deduction in stress rate relaxation. Results have revealed the best rutting resistance for 6% HDPE. It also showed an improvement of 95.27% in G*/Sin (δ) which increased the performance of the bituminous mix. Similarly, the addition of 4% LDPE resulted in maximum dynamic viscosity irrespective of the temperatures. Moreover, fatigue resistance has shown a significant change with the HDPE and LDPE. The festinating features of waste plastic modified binder make it important to be used in the new construction of roads to address the high viscosity and mixing problems produced by plastic waste and to improve the performance of flexible pavements all over the world.

Comparison of Material Properties of Lightweight Concrete with Recycled Polyethylene and Expanded Clay Aggregates

In Ethiopia, scraps of high-density polyethylene (HDPE) pipes and crushed glass bottles are largely considered waste and are not being recycled or reused. In this study, it is aimed at experimentally processing HDPE scrap and mixing it with waste glass powder to produce a composite material with the potential to become a matrix and reinforcement material for pipes. Six samples were produced with varying percentages of the reinforcement and matrix. Their mechanical and physical properties were measured according to composite standards. The compounding mechanism and chemical reactions were properly performed for each sample and crosslinking between all materials was characterized. The theoretical density of the samples was determined using the rule of mixture. After conducting all experiments, a composite sample with 27.645 MPa of tensile strength, 22.061 MPa of tear strength, an increase in hardness, an average actual density of 1.1195 g/cm3 and an increase in abrasion resistance capability was selected. This study demonstrates the potential for recycling HDPE scraps and waste glass powder into a composite material with desirable mechanical and physical properties for use in the production of pipes. The experimental results indicate that the waste HDPE and glass powder can be effectively processed and utilized as a cost-effective and sustainable alternative to virgin materials for the production of composite materials. The use of waste materials in this manner can not only reduce the environmental impact of industrial waste but also create new opportunities for the recycling and repurposing of waste materials. Furthermore, the resulting composite material can offer improved mechanical properties such as tensile strength, tear strength and abrasion resistance, compared to traditional materials. This study provides valuable insights into the development of sustainable composite materials and offers a promising avenue for future research on the recycling and reuse of waste materials.

The growing challenges of environmental sustainability and waste management in the construction industry have spurred the search for innovative materials to enhance asphalt mixtures. Conventional porous asphalt faces limitations in durability and performance under varying traffic and weather conditions. Moreover, the disposal of oyster shells and High-Density Polyethylene (HDPE) waste poses significant environmental concerns. This study evaluates the effect of oyster shell ash (OSA) as a filler and HDPE waste as an asphalt substitute in porous asphalt mixtures. Testing was conducted to determine the Optimum Asphalt Content (OAC) based on three primary parameters: Cantabro Loss (CL), Void In Mix (VIM), and Asphalt Flow Down (AFD). The results indicate that the OAC value is 5.8%. In the Void In Mix (VIM) test, the best results were obtained with a variation of 50% OSA: 50% PC and 4% and 6% HDPE, yielding VIM values of 18.49% and 18.16%, respectively, which meet the AAPA (2004) standard requirement of 18-25%. The Asphalt Flow Down (AFD) test results showed that the same mixture produced AFD values of 0.09% and 0.10%, well within the maximum limit of 0.3%. The optimal values for the Cantabro Loss (CL) parameter were also achieved with the same combination, resulting in 32.67% and 30.07%, which comply with the maximum threshold of 35%. This study concludes that the combination of oyster shell ash (50% OSA: 50% PC) and HDPE (4% and 6%) performs well in porous asphalt mixtures, meeting the standards for durability, strength, and stability in road pavement applications.

Air co-gasification process of LDPE/HDPE waste based on thermodynamic modeling: Hybrid multi-criteria decision-making techniques with sensitivity analysis

Clean and green environment can be achieved by utilising waste materials into the cement concrete. In this investigation, waste materials like high-density polyethylene (HDPE) waste plastic and copper slag were utilised in cement concrete. This investigation reveals potential engineering efficiency of the copper slag and HDPE plastic fibres in cement concrete. In this work the specimens are made with 60% cement replaced with copper slag and with the addition of 85mm long 0.4mm diameter HDPE fibre at 0%, 0.2%, 0.4% and 0.6% fibre reinforced cement concrete. The specimens were applied elevated temperatures at 200oC, 400oC, 600oC and 900oC. The compressive strength of HDPE reinforced cement concrete is increased with the addition of fibre, the tensile strength and flexural (rupture) moduli were also increased. Fibres excellently improved the flexural ductility after cracking and also improve serviceability properties. Durability tests like water absorption and sorptivity were conducted with and without elevated temperatures and concluded that the HDPE fibre reinforced concrete reduces water absorption, hence water retaining structures can be built using HDPE fibre concrete. All results show that HDPE fibres are positively active in cement concrete and improving its durability properties.

Uji kaji ini dijalankan untuk mengkaji sifat fizikal dan terma bagi formulasi campuran polietilina berangkai silang gred acuan putaran berasaskan kebolehprosesan. High Density Polyethylene (HDPE) gred acuan putaran dicampur dengan pelbagai komposisi HDPE dan Low Density Polyethylene (LDPE) menggunakan penyemperit skru pendua. Indeks Aliran Lebur (MI) campuran dikaji berasaskan ASTM D 1238. Komposisi campuran tersebut disambung silang secara kimia dengan agen penyambung silang silane menggunakan 'two roll mill’. Kemudian sambung silang lembapan dilakukan di dalam water bath selama 4 jam dan 8 jam. Kandungan gel diukur mengikut ASTM D 2765 bagi menentukan darjah penyambungan silang. Bagi analisis terma,hanya sampel yang disambung silang dengan 2.0 phr agen penyambung silang silane dikaji dengan Kalorimetri Pengimbasan Pembeza (DSC) berdasarkan ASTM 3417. Ujian kestabilan terma bagi XLPE silane dilakukan dengan menggunakan Penganalisa Termogravimetri (TGA) mengikut ASTM D 3850. Keputusan bagi Indeks Aliran Lebur (MI) menunjukkan campuran antara HDPE gred acuan putaran dengan HDPE lebih tinggi berbanding LDPE, dengan itu menambahbaik kebolehprosesan bahan. Ketumpatan campuran antara HDPE gred acuan putaran HDPE meningkat sedikit manakala campuran dengan LDPE menurun sedikit. Sampel yang dicampur dengan HDPE tidak menunjukkan perubahan bagi suhu lebur, Tm manakala darjah penghabluran, Xc, mengalami penurunan. Sampel campuran dengan LDPE pula, Tm dan Xc menurun dengan bertambahnya komposisi LDPE menunjuk kepada kebolehprosesan yang lebih baik. Kandungan gel meningkat dengan penambahan kepekatan silane dan tidak bergantung kepada komposisi campuran. Masa pengawetan yang lebih panjang menghasilkan nilai gel yang tinggi. Kestabilan terma PE yang dirangkai silang lebih tinggi berbanding HDPE yang tidak dirangkai silang. Oleh yang demikian, penyambungan silang secara silane menambahkan kestabilan campuran. Kata kunci: HDPE rangkai silang silane, acuan putaran, sifat fizikal, sifat terma dan kebolehprosesan This study is aimed at investigating the physical and thermal properties of the modified rotational molding grade cross-linked polyethylene compound with respect to process ability. Rotational molding grade High Density Polyethylene (HDPE) was blended at various compositions with HDPE and Low Density Polyethylene (LDPE) using twin screw extruder. The melt index of the blends was studied according to ASTM D 1238. The blended compositions were chemically cross-linked with various amount of silane cross-linking agent using two roll-mill. Water curing was then undertaken at 100C in water bath for 4 and 8 hours. Gel content was measured according to ASTM D 2765 to determine the degree of cross-linking. For thermal analysis, only samples crosslinked with 2.0 phr silane cross-linking agent were investigated on the Differential Scanning Calorimetry (DSC) according to ASTM D 3417. The thermal stability test of the silane Crosslinkable Polyethylene (XLPE) was performed by Thermogravimetric Analyzer (TGA) according to ASTM D 3850. Results on melt index (MI) indicated that the rotational molding grade HDPE blended with HDPE showed higher MI compared to that with LDPE thus improved process ability. The density of rotational molding grade HDPE with HDPE was slightly increased whereas that blended with LDPE was slightly decreased. Samples blended with HDPE, melting temperature, Tm, barely changed and degree of crystallinity, Xc, decreased with compositions. Samples with LDPE Tm and Xc decreased with compositions thus improved process ability. As the silane concentrations increased, the gel content after curing was also increased but independent of compositions. Longer curing time resulted in higher gel content. Thermal stability of the crosslinked HDPE was higher than the uncross-linked HDPE, thus silane cross-linking help to stabilize the blends. Key words: Silane cross–linked high density polyethylene, rotational molding, thermal properties, physical properties and process ability

Catalytic degradation of low and high density polyethylenes using ethylene polymerization catalysts: Kinetic studies using simultaneous TG/DSC analysis

Oriented structure and anisotropy properties of polymer blown films: HDPE, LLDPE and LDPE

The influence of thermoplastic/bagasse fiber ratio, as well as electron beam irradiation on the physicomechanical properties of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) composites has been investigated. The concentration of bagasse fibers ranges from 20 to 80 wt%. The results indicate that there is deterioration in the properties as fiber concentration increased; however, it becomes significant only beyond 50% (w/w) bagasse fibers in both LDPE and HDPE composites. Also, the data show that this decrease in the properties is more pronounced in HDPE rather than LDPE composites. It can be noticed that enhancing adhesion between fibers and thermoplastics can be achieved by irradiation of the thermoplastic phase prior to mixing at 10 up to 60 kGy; a maximum improvement in the properties is observed at 40 and 10 kGy for LDPE and HDPE, respectively. From the data it can be seen that the increase in the flexural properties is higher than 100%, while it does not exceed 65% for impact toughness. On the other hand, the reduction in water absorption is not more than 5.5%. Also, examining SEM micrographs reveals that there is some sort of adhesion between fibers and thermoplastics phases.

Suitable disposal pathways of waste plastics and coal fly ash have yet not been established which is a matter of great environmental concern. Waste low-density polyethylene (LDPE) and high-density polyethylene (HDPE) were degraded using a semi-batch reactor along with acid or alkali modified fly ash catalyst. The high yield of liquid fuel product (about 87.24 wt%) was achieved for low-density polyethylene at a polymer and catalyst ratio of 25 w/w. About 96% conversion was found with very few amount of gaseous fuels. Both of the waste plastics were degraded at 400–450 °C. The liquid products were analyzed using Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H, 13C, and DEPT-135 NMR), and gas chromatography–mass spectrometry (GC–MS). Fly ash is an efficient catalyst to degrade waste plastic into light weight liquid (gasoline and kerosene) hydrocarbons. The NMR results accompanied by GC–MS data ensure that obtained fuels contain both aliphatic (saturated and unsaturated) and aromatic hydrocarbons. This plastic-to-fuel technology should be commercialized owing to be profitable and eco-friendly.

Creeping Wild Rye (CWR), Leymus triticoides, is a salt-tolerant and perennial grass, which is planted in San Joaquin Valley, California in the USA to lower salt contents from drainage irrigation water to prevent water streams and soil from pollution and alkalization, respectively. In this study, CWR was used as raw materials to manufacture medium-density particleboard. The objective of this research was to characterize the qualities (mechanical properties and water resistance) of CWR particleboards bonded by high density polyethylene (HDPE) from recycled food carrying bags, polymeric methane diphenyl diisocyanate (PMDI) and/or rice bran adhesive (RBA). The evaluated properties of particleboard included tensile strength (TS), modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond strength (IB). Water absorption and thickness swell were used to evaluate the water resistance properties of finished CWR particleboard. The effects of the amount of HDPE, PMDI and/or RBA on the qualities of finished particleboards were determined. The partial PMDI replacement with RBA did not compromise the mechanical quality, but yield lower water resistance. Adding HDPE, however, improved the overall qualities of particleboards. In order to optimize the properties of medium-density particleboard made from CWR and HDPE, an orthogonal experimental design was employed. Results showed that up to 30% PMDI can be replaced by adding 20% HDPE with size of 10×10mm to manufacture the particleboard with higher mechanical strength and the water resistance particleboards than without HDPE.

Biodegradable plastics can be produced from mixing synthetic plastic waste with natural polymers. In this research, biodegradable plastic from High Density Polyethylene (HDPE) waste and starch from palm oil empty fruit bunch was made. The HDPE wastes used were modified with 1% maleic anhydride as crosslinking agent with the help of 1% benzoyl peroxide as initiator. The method of mixing the material was done with two different methods, namely the reflux method and the melt blending method with variation of the ingredients added with a fixed ratio of HDPE-g-MA: Starch (60:40). Conclusion from the analysis of the mechanical properties, thermal properties and morphological properties, biodegradable plastic with rheomix method has advantages over reflux method where the tensile strength value is 15.970 N/m2 and 3.518% elongation value. The thermal properties can be seen from the melting point at a temperature of 128.3° C, decomposition point at 488.23° C and carbon residue from Thermal Gravimetry Analysis (TGA) test is 2.537%. From the analysis of morphological properties as can be seen in SEM observation showed biodegradable plastic made by melt blending method have a more even mixture that minimizes the pores on biodegradable plastic produced.

Catalytic co-pyrolysis of sugarcane bagasse and waste high-density polyethylene over faujasite-type zeolite

Corncob powder filled high-density polyethylene (HDPE) composites were prepared by extrusion. The microstructure, water absorption, mechanical properties, and crystallinity of composite at different corncob powder content were investigated. Results demonstrated that when the corncob powder levels were moderate and uniformly dispersed within the HDPE matrix, the powder acted as a reinforcing agent. As the corncob content increased, the water absorption of the resulting composite gradually increased, which adversely affected the composite’s water resistance. Flexural strengths and moduli initially increased with increasing corncob powder levels, and then consequently decreased at higher powder levels; maximum values for flexural properties were achieved at 40% corncob powder content. The composite’s impact strength and toughness weakened with corncob powder addition. The X-ray diffraction and differential scanning calorimetry analyses indicated that when the corncob content increased, the peak crystallization and melting temperatures of the matrix increased and decreased, respectively. Meanwhile, the presence of the corncob restricted the movement and arrangement of the HDPE polymer chains, which affected HDPE crystal growth and causing a decrease in crystallinity.