High-density Polyethylene Matrix Research Articles

Probing Viscoelastic Properties and Interfaces in High-Density Polyethylene Vitrimers at the Nanoscale Using Dynamic Mode Atomic Force Microscopy.

Vitrimers are a new class of heterogeneous polymers that combine the best features of thermosets with those of thermoplastics. The introduction of cross-links strongly changes the viscoelastic behavior of vitrimer materials. However, the characterization and understanding of the nanostructures and interfaces in vitrimers resulting from dynamic cross-linking formation remain a major challenge. Here, using dynamic modes of atomic force microscopy (AFM), namely intermodulation AFM (ImAFM) and AFM-based dynamic mechanical analysis (AFM-nDMA), local viscoelastic properties and interfaces at the nanoscale length of high-density polyethylene (HDPE) vitrimer materials are reported. ImAFM imaging in combination with the k-means clustering algorithm clearly reveals two distinct phases in the vitrimer system with highly different viscoelastic properties. AFM-nDMA further provides quantitative nanoviscoelastic properties at the nanoscale to confirm that there is a cross-linking-rich aggregation area forming a nanosize network structure in the cross-linking-poor matrix phase. The cross-linking-rich region shows a similar elastic modulus but much higher adhesion force measured by AFM compared to the cross-linking-poor HDPE matrix. Furthermore, the frequency influence on the local viscoelastic properties of HDPE vitrimer at the nanoscale was initially screened. The observed HDPE vitrimer nanostructures and viscoelastic properties at the nanoscale also provide explanations on the observed bulk HDPE vitrimer crystallinity decrease and dimensional stability increase compared to HDPE. Therefore, probing the viscoelastic properties and interfaces of HDPE vitrimer provides important insights into understanding of the correlations between the vitrimer nanostructure and the bulk mechanical and rheological behaviors.

Preparation, characterization, and antistatic applications of high‐density polyethylene/polyaniline blends

AbstractTo obtain electrostatic charge dissipative (ESD) materials, high‐density polyethylene (HDPE) and polyaniline (PANI) blends are synthesized by the solution blending method. To prepare the blends, 0.5, 1.0, and 3.0 wt% of PANI are introduced into the HDPE matrix. The prepared blends are investigated by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), and scanning electron microscope (SEM). Additionally, stress–strain curves are used to examine the blends' mechanical properties. Polyaniline additions indicated an increase in thermal stability by approximately 1°C in the blends but decrease in mechanical properties. The four‐probe technique is used to determine the electrical conductivity of blends, which is found to be between 10−7 and 10−10 S/cm. The results of the conductivity values have indicated that all blends have great potential to be used as antistatic materials. For antistatic applications, the ESD performance of the blends is determined at different corona voltages. Blends achieved the antistatic requirements with a 10% cutoff decay time of approximately 2.0 s and a 1/e time of approximately 1.0 s, demonstrating quick dissipation of static charges. According to antistatic decay times, it has been shown that all blends obtained in this study can be used as antistatic material at 3 kV corona voltage.

Effects of processing temperature, pressure, and fiber volume fraction on mechanical and morphological behaviors of fully-recyclable uni-directional thermoplastic polymer-fiber-reinforced polymers

This work explores a type of composite called thermoplastic polymer-fiber-reinforced polymers (PFRPs), often referred to as self-reinforced composites (SRCs). A representative PFRP was exemplified using unidirectional (UD) ultra-high-molecular-weight polyethylene (UHMWPE) fibers embedded in a high-density polyethylene (HDPE) matrix. The effects of compression molding temperature and pressure on the mechanical and morphological behaviors of the filament-wound PFRPs with various fiber volume fractions (Vf) were experimentally investigated.The results elucidate the evolution of morphologies and tensile properties of the PFRPs due to thermal melting, fiber misalignment from pressure, and Vf-induced structural variance, which has not been comprehensively reported yet. The highest specific tensile strength and modulus of the PFRP laminae reach 600 MPa/(g/cm3) and 31 GPa/(g/cm3), respectively. These properties are comparable to glass-/aramid-fiber-reinforced polymers (GFRPs, GFRTPs, AFRPs, and AFRTPs), with PFRPs exhibiting better ductility (specific strain at peak load ≈ 4 %/(g/cm3)).The motivation for this work was the high recyclability of PFRPs, which can be recycled by melting both the fibers and the matrix, and then reshaped them for re-manufacturing composites to maximize the efficiency in material reuse. This process simplifies the implementation of closed-loop recycling, re-manufacturing, and reuse to support sustainability in composites. This work aims to contribute to advancing thermoplastic PFRPs for their potential applications in various industries.

Optimizing the rheological and mechanical properties of ultra-highly filled wood fiber/polyethylene composites through binary alloy matrix strategy

Enhancing the interfacial adhesion and rheological behavior of ultra-highly filled wood-plastic composites (UH–WPCs) presents a considerable challenge. We developed a bespoke binary alloy matrix of high-density polyethylene (HDPE) and maleated polyethylene (MAPE) to fabricate UH-WPCs with 70–90 wt% filler contents. Fourier-transform infrared spectroscopy and thermogravimetric analysis validated that about 22.3 % of MAPE engaged in esterification with wood fibers (WFs) in 80 wt% loading UH-WPCs, manifesting in noteworthy plasticization as evidenced by WFs' sheet-like structures. Rheological assessments illustrated that higher MAPE proportions reduced the viscosity of both the specialized alloy and UH-WPC melts significantly. By fine-tuning the MAPE to HDPE ratio to 16:2, we achieved marked enhancements in UH-WPCs' mechanical properties and dimensional stability: tensile strength and flexural strength increased by up to 141.7 % and 151.0 %, respectively, while creep strain and equilibrium water absorption decreased by as much as 27.3 % and 36.7 %. This research lays a robust scientific foundation for the efficient processing and enhancement of UH-WPCs, highlighting its potential for substantial improvements in mechanical performance, stability, and processability.

Post-consumer high-density polyethylene matrix reinforced by sugarcane bagasse fibers treated in stearic acid solution

The study aimed to advance composite technology by exploring the potential of recycled materials, specifically high-density polyethylene (HDPE) composites reinforced with sugarcane bagasse fibers. This research not only addresses environmental concerns by utilizing recyclable materials but also aims to offer significant technical, economic, and social advantages. The investigation focused on formulating and evaluating these composites, considering varying proportions of untreated sugarcane bagasse fibers and examining the effects of chemical treatment with stearic acid at different temperatures. Using a conical twin-screw extruder and injector, the researchers produced and analyzed the composites both morphologically and mechanically. The principal findings indicated that the inclusion of untreated fibers improved the stiffness and tensile strength of the composites. Nevertheless, adhesion between the fibers and the matrix was compromised, especially with higher fiber concentrations. Chemical treatment at 40 °C significantly improved fiber/matrix interactions, thereby enhancing the reliability and mechanical properties of the composites. This treatment led to substantial increases in tensile and compressive strengths, particularly noticeable in composites containing 10%–15% fiber by weight. These results not only demonstrate the feasibility of using recycled HDPE and sugarcane bagasse fibers in composite materials but also suggest avenues for further exploration. Future research could delve deeper into optimizing chemical treatment processes to achieve even better adhesion and mechanical performance. Moreover, exploring broader applications in industries such as automotive, aerospace, naval, civil engineering, and packaging could unlock new opportunities for these sustainable composites. This study thus paves the way for advancing composite technology towards more environmentally friendly and economically viable solutions.

Effect of temperature on the uniaxial tensile properties of wood plastic composites: Experimental investigation and numerical analysis

Seven groups of uniaxial tensile experiments on wood plastic composites with a High Density Polyethylene (HDPE) matrix at different temperatures were completed in this paper. The test temperatures ranged from -60 °C to 60 °C, with a temperature difference of 20 °C for each group. All samples exhibited tensile brittle fracture. The test results showed that the tensile strength of the specimens decreased continuously with increasing temperature. Taking 0 °C as the reference temperature, the ultimate strength of the sample at -60 °C was 1.63 times that at 0 °C. When the temperature was 60 °C, this value was 0.41. Then, it can be calculated that the ratio of the strength of the sample at -60 °C to that at 60 °C was approximately 3.93, and the corresponding ratio of the elastic modulus was approximately 4.52. This shows that the mechanical properties of WPC are sensitive to changes in temperature. The variation coefficient of the average strength and elastic modulus of WPC for different specimens at different temperatures was less than 0.17, showing good stability due to the small dispersion of mechanical properties among different samples at any specific temperature.

Enhancing Mechanical Performance of High-Density Polyethylene at Different Environmental Conditions with Outstanding Foamability through In-Situ Rubber Nanofibrillation: Exploring the Impact of Interface Modification.

In this study, we utilized in situ nanofibrillation of thermoplastic polyester ether elastomer (TPEE) within a high-density polyethylene (HDPE) matrix to enhance the rheological properties, foamability, and mechanical characteristics of the HDPE nanocomposite at both room and subzero temperatures. Due to the inherent polarity differences between these two components, TPEE is thermodynamically incompatible with the nonpolar HDPE. To address this compatibility issue, we employed a compatibilizer, styrene/ethylene-butylene/styrene copolymer-grafted maleic anhydride (SEBS-g-MA), to reduce the interfacial tension between the two blend components. In the initial step, we prepared a 10% masterbatch of HDPE/TPEE with and without the compatibilizer using a twin-screw extruder. Subsequently, we processed the 10% masterbatch further through spun bonding to create fiber-in-fiber composites. Scanning electron microscopy (SEM) analysis revealed a significant reduction in the spherical size of HDPE/TPEE particles following the inclusion of SEBS-g-MA, as well as a much smaller TPEE nanofiber size (approximately 60-70 nm for 5% TPEE). Moreover, extensional rheological testing revealed a notable enhancement in extensional rheological properties, with strain-hardening behavior being more pronounced in the compatibilized nanofibrillar composites compared to the noncompatibilized ones. SEM images of the foam structures depicted substantial improvement in the foamability of HDPE in terms of the cell size and density following the nanofibrillation process and the use of the compatibilizer. Ultimately, the in situ rubber fibrillation and enhancement of HDPE and TPEE interface using a compatibilizer led to increasing the HDPE ductility at room and subzero temperatures while maintaining its stiffness.

Shish‐kebab structure evolution of HDPE/UHMWPE during hot drawing

AbstractUsing a solution‐mixing method, this research aimed to fabricate high‐density polyethylene (HDPE)/ultra‐high molecular weight polyethylene (UHMWPE) composite materials with uniform dispersion. By incorporating a small quantity of UHMWPE as a nucleating agent, additional contact points were introduced to enhance the crystallization rate of the HDPE matrix. Thermal stretching experiments were conducted on composite systems with varying UHMWPE contents and molecular weight additions at different temperatures. Elevating the stretching temperature was found to decrease the yield strain and yield strength, extend the stage of tensile plastic deformation, and diminish the overall mechanical properties of the composite material. Notably, stretching at temperatures ranging from 90 to 110°C accentuated the development of internal crystal orientation structures. Under low strain conditions, crystal slip was observed to be concentrated, with single crystals undergoing continuous stretching and breaking, resulting in a decrease in the long period. Conversely, at high strains, the induced formation of oriented lamellar structures was observed.Highlights Prepared HDPE/UHMWPE blends by UHMWPE with varying molecular weights. Analyzed the alterations in the HDPE/UHMWPE blends' internal crystal structure. Influence of UHMWPE addition, temperature on the evolution of crystal structure.

Exploring the Effects of Nano-CaCO3 on the Core-Shell Structure and Properties of HDPE/POE/Nano-CaCO3 Ternary Nanocomposites.

To address the dilemma of the stiffness and toughness properties of high-density polyethylene (HDPE) composites, titanate coupling agent-treated CaCO3 nanoparticles (nano-CaCO3) and ethylene-octene copolymer (POE) were utilized to blend with HDPE to prepare ternary nanocomposites via a two-sequence-step process. Meanwhile, a one-step process was also studied as a control. The obtained ternary nanocomposites were characterized by scanning electron microscopy (SEM), Advanced Rheometrics Expansion System (ARES), Dynamic Mechanical Analysis (DMA), wide-angle X-ray diffraction analysis (WXRD), and mechanical test. The SEM results showed one or two CaCO3 nanoparticles were well-encapsulated by POE and were uniformly dispersed into the HDPE matrix to form a core-shell structure of 100-200 nm in size by the two-step process, while CaCO3 nanoparticles were aggregated in the HDPE matrix by the one-step method. The result of the XRD showed that the nano-CaCO3 particle played a role in promoting crystallization in HDPE nanocomposites. Mechanical tests showed that the synergistic effect of both the POE elastomer and CaCO3 nanoparticles should account for the balanced performance of the ternary composites. In comparison with neat HDPE, the notched impact toughness of the ternary nanocomposites of HDPE/POE/nano-CaCO3 was significantly increased. In addition, the core-shell structure absorbed the fracture impact energy and prevent further propagation of micro-cracks, thus obtaining a higher notched Izod impact strength.

Developing Eco-Friendly 3D-Printing Composite Filament: Utilizing Palm Midrib to Reinforce High-Density Polyethylene Matrix in Design Applications.

Designers actively pursue the use of novel materials and concepts in furniture and interior design. By providing insights into their processing behavior and suitability for 3D-printing processes, this research helps to highlight the potential of using waste materials to create more environmentally friendly and sustainable 3D-printing filaments that can be used in furniture and interior design. Furthermore, the study evaluates the effect of incorporating palm midrib nanoparticles (DPFNPs) to reinforce a high-density polyethylene (HDPE) matrix with different loadings such as 10, 20, 30, 40, and 50 wt.%. The composites were extruded into filaments using a manual extruder, which was then utilized to fabricate 3D-printed specimens using a 3D-printing pen. The effect of adding DPFNPs on the composite's chemical, thermal, and mechanical properties was evaluated, with a particular focus on how these modifications influence the melt flow rate (MFR) and, subsequently, the material's printability. The results revealed that HDPE and filament composites presented similar FTIR spectra. On the other hand, the filament composites presented an increase in the thermal stability and a decrease in the mechanical strength with increasing DPFNP content in the HDPE matrix. The filaments were successfully printed using a 3D-printing pen. Thus, using DPFNPs in the HDPE matrix presents a low-cost alternative for filament production and may expand 3D-printing applications in interior and furniture design with more sustainable materials. Future work will delve into optimizing these composites for improved printability and assessing their recyclability, aiming to broaden their applications in 3D printing and beyond.

Assessment of mechanical and physicochemical properties of palm fiber composites: Effect of alkaline treatment and volume alterations

This study assesses the impact of alkaline treatments and volume fractions on biocomposites composed of a high-density polyethylene (HDPE) matrix reinforced with date palm tree fibers (FPDS). Tensile tests were conducted on both untreated and NaOH-treated biocomposites. Additionally, fiber analysis was performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results reveal higher strength and stiffness compared to HDPE, albeit with limited plasticity making the material brittle. The NaOH treatment enhances certain mechanical properties. Further assessments encompassed hardness, density, melt index, and Izod impact tests. Two volume fractions, 20% and 25%, of FPDS were tested. The study establishes a correlation between empirical predictions and artificial neural network (ANN) models. Notably, an ANN architecture consisting of two input factors, 10 hidden nodes, and one output provides the analysis of mechanical properties. This investigation highlights the potential of FPDS-reinforced HDPE biocomposites, emphasizing their mechanical performance under various treatments and fiber levels.

Influence of Strong Shear Field on Structure and Performance of HDPE/PA6 In Situ Microfibril Composites.

As one of the most widely applied general-purpose plastics, high-density polyethylene (HDPE) exhibits good comprehensive performance. However, mechanical strength limits its wider application. In this work, we introduced the engineering plastic PA6 as a dispersed phase to modify the HDPE matrix and applied multiple shears generated by vibration to the polymer melt during the packing stage of injection molding. SEM, 2D-WXRD and 2D-SAXS were used to characterize the morphology and structure of the samples. The results show that under the effect of a strong shear field, the dispersed phase in the composites can form in situ microfibers and numerous high-strength shish-kebab and hybrid shish-kebab structures are formed. Additionally, the distribution of fibers and high-strength oriented structures in the composites expands to the core region with the increase in vibration times. As a result, the tensile strength, tensile modulus and surface hardness of VIM-6 can reach a high level of 66.5 MPa, 981.4 MPa and 72, respectively. Therefore, a high-performance HDPE product is successfully prepared in this study, which is of great importance for expanding the application range of HDPE products.

Assessing the recycling potential of thermosetting polymer waste in high-density polyethylene composites for safety helmet applications

Abstract The rising demand for thermosetting polymers has resulted in the production of large amounts of industrial waste. Environmental issues due to waste landfills and increased raw material costs for new product development have led to the development of innovative recycling methods. This study focuses on the development of a product (helmet shell) by reinforcing thermosetting polymer waste (TPW) as a filler in a high-density polyethylene (HDPE) matrix. The HDPE and TPW were converted into extrudates using a twin-screw extruder. Then, the extrudate was pelletized to use as raw material for the injection molding machine. The HDPE/TPW composites were fabricated using injection molding. Maleic anhydride-grafted polyethylene was employed as a compatibilizer. In the composite, the TPW volume was reinforced at various weight percentages, ranging from 0 to 35 wt%. The mechanical, thermal, and viscoelastic properties of the composites can be enhanced by uniformly dispersing TPW in the HDPE matrix. However, it is difficult to achieve uniform dispersion at higher TPW volumes owing to the agglomeration effect. According to these findings, the mechanical properties were enhanced by up to 30 wt% addition of TPW. The findings suggest that the proposed composite has sufficient mechanical properties to be suitable for the fabrication of helmet shells.

Mechanical Properties of Luffa Fiber Reinforced Recycled Polymer Composite

Environmental issues over the eventual fate of post-consumer polymers can be dealt with in two separate ways which is recycling or using biodegradable polymers. However, it is evident that recycling polymers from post-consumer polymers can decrease the mechanical properties over time. Hence, to strengthen the recycled polymers, integrating fibers, such as luffa, into the High-Density Polyethylene (HDPE) matrix, was carried out to produce a fiber reinforced recycled polymer (FRrP) composite. The tensile testing of the FRrP composite shows that the 10% fiber volume fraction (FVF) composite exhibits a higher tensile strength of 3.9% than the neat recycled HDPE (RHDPE). In terms of Young’s Modulus, the 5% FVF of FRrP is shown to have a higher value than the neat RHDPE by 54%. The low density of luffa fibers also contributes to the composites lightweight character. The impact testing shows that the FRrP enhances the impact properties when compared to the neat RHDPE. The peak load, perforation energy, and the total energy absorbed by the FRrP indicate an increasing trend when luffa, of up to 15% FVF, is added as the reinforcement. Thus, the addition of luffa as reinforcement in RHDPE shows significant potential as a high-performance, sustainable, and environmentally friendly material, such as automotive parts and protective gear.

Rheological and Thermal Characterization of Glycerol Monostearate (GMS) as Compatibilizer on Polyethylene-Palm Stearin Composite

Addition of high percentage of palm stearin (PS) into a blend with high density polyethylene (HDPE) may result in the blend instability and poor flowability of the composite during injection moulding process. The undesirable effect of the PS addition arises from lack of interaction between the PS and HDPE matrix. To improve the interaction between the two components, a compatibilizer was added to the blend. The objective of this work is to study the effect of glycerol monostearate (GMS) compatibilizer concentration (1-5 wt%) on the HDPE-PS composite with PS content of 40 wt.%. The thermal properties of the HDPE-PS composite were characterized using torque analysis, differential scanning calorimetry (DSC) analysis and rheology analysis. It was found that melting temperature of the HDPE-PS composite decreases with GMS concentration. The presence of GMS in the HDPE-PS composite had improved composite flowability indicate suitability of the GMS as compatibilizer for the HDPE-PS composite.

Multifunctional HDPE/Cu biocidal nanocomposites for MEX additive manufactured parts: Perspectives for the defense industry

In this study, we investigated the performance improvement caused by the addition of copper (Cu) nanoparticles to high-density polyethylene (HDPE) matrix material. Composite materials, with filler percentages of 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0 wt% were synthesized through the material extrusion (MEX) 3D printing technique. The synthesized nanocomposite filaments were utilized for the manufacturing of specimens suitable for the experimental procedure that followed. Hence, we were able to systematically investigate their tensile, flexural, impact, and microhardness properties through various mechanical tests that were conducted according to the corresponding standards. Broadband Dielectric Spectroscopy was used to investigate the electrical/dielectric properties of the composites. Moreover, by employing means of Raman spectroscopy and thermogravimetric analysis (TGA) we were also able to further investigate their vibrational, structural, and thermal properties. Concomitantly, means of scanning electron microscopy (SEM), as well as atomic force microscopy (AFM), were used for the examination of the morphological and structural characteristics of the synthesized specimens, while energy-dispersive X-ray spectroscopy (EDS) was also performed in order to receive a more detailed picture on the structural characteristics of the various synthesized composites. The corresponding nanomaterials were also assessed for their antibacterial properties regarding Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with the assistance of a method named screening agar well diffusion. The results showed that the mechanical properties of HDPE benefited from the utilization of Cu as a filler, as they showed a notable improvement. The specimen of HDPE/Cu 4.0 wt% was the one that presented the highest levels of reinforcement in four out of the seven tested mechanical properties (for example, it exhibited a 36.7% improvement in the flexural strength, compared to the pure matrix). At the same time, the nanocomposites were efficient against the S. aureus bacterium and less efficient against the E. coli bacterium. The use of such multi-functional, robust nanocomposites in MEX 3D printing is positively impacting applications in various fields, most notably in the defense and security sectors. The latter becomes increasingly important if one takes into account that most firearms encompass various polymeric parts that require robustness and improved mechanical properties, while at the same time keeping the risk of spreading various infectious microorganisms at a bare minimum.

Influence of modified phosphogypsum content on the properties of HDPE/phosphogypsum composites

Phosphogypsum has received increasing attention for solid waste with high production and environmental pollution. This study treated phosphogypsum with the silane coupling agent 3-(methacryloyloxy) propyltrimethoxysilane (KH570) to create modified HDPE/phosphogypsum composites. The modified phosphogypsum was then melted and blended with high-density polyethylene (HDPE). Thermal weight loss (TG), differential scanning calorimetry (DSC), and rheological and mechanical property testing were used to study the impact of the changed phosphogypsum content on the properties of the composites. The outcomes demonstrate that even at low filling levels, the modified phosphogypsum may be evenly distributed throughout the matrix. Furthermore, the addition of increased phosphogypsum filling enhances the mechanical characteristics of the HDPE matrix.

The impact of chemical treatment and gamma-ray irradiation on the okra hessian cloth reinforced high-density polyethylene composites

Okra hessian cloth-reinforced high-density polyethylene (HDPE) thermoplastic composites were prepared and characterized with both raw and alkali-treated fibers. The fiber contents were optimized for both the raw Okra thermoplastic composites and the alkali-treated Okra thermoplastic composites, and the optimum value of fiber content was 55 wt%. Samples that were alkali-treated and had 55 wt% fibers were subsequently exposed to gamma radiation at doses of 2.5, 5, and 7.5 kGy. Only the sample subjected to 5 kGy showed improved performance. Treated composites exhibited higher crystallinities than the untreated samples as observed by X-Ray diffraction analysis. The rupture surface micrographs of the composites exposed to 5 kGy gamma radiation revealed more compact than others. By using Fourier transform infrared spectroscopy analysis of composites, it was found that 5 kGy dose sample showed enhanced cross-linking between Okra fibers and HDPE matrix. The irradiated composite showed less water intake than the alkali-treated samples. Composites subjected to 5 kGy gamma rays showed improved tensile strength and Young’s modulus of values 66 MPa and 1925 MPa, respectively. Compared to raw and treated composites, the irradiated composites with a radiation dose of 5 kGy showed improved structural, mechanical, and thermal properties.

Structural Characteristics and Improved Thermal Stability of HDPE/Calcium Pimelate Nanocomposites

In the present research work, calcium pimelate (CaPim) was synthesized and investigated as an additive for high-density polyethylene (HDPE). HDPE/CaPim nanocomposites were prepared by melt-mixing, with CaPim content ranging from 0.1% to 1%, affording white homogeneous materials. The chemical structure of the nanocomposites and the incorporation of CaPim was confirmed by infrared spectroscopy. The surficial morphology and the additive distribution were examined by scanning electron microscopy. Differential scanning calorimetry and X-ray diffraction measurements showed that the thermal transitions and crystal structure of HDPE are not affected by the incorporation of CaPim, while the mechanical properties are retained overall. This study focuses on the thermal degradation of HDPE nanocomposites, investigating the degradation mechanism and kinetic parameters through various analytical methods. Isoconversional techniques, including the Friedman method, Vyazovkin analysis, and Ozawa Flynn Wall analysis, were employed to calculate activation energies (Eα). The degradation mechanism and kinetic triplet were determined based on a multivariate non-linear regression method (model-fitting). Finally, the presence of a CaPim additive was shown to increase the Eα of thermal degradation, consistent with the calculated dependence of Eα on the degree of conversion and the improved thermal stability of the HDPE matrix.

Preparation of nano zinc borate and investigation of flame-retardancy of ternary combination nano zinc borate/red phosphorus/expandable graphite on HDPE

Nano zinc borates were successfully synthesised from aqueous solutions of zinc sulfate, boric acid, and sodium hydroxide via the precipitation method. The effects of pH, temperature, and surfactants on the structure and morphologies of nano zinc borates were investigated. The nano zinc borates obtained at the pH of 7 to 8 were well-crystallised monophase Zn[B3O4(OH)3]. The morphologies of nano zinc borates were highly impacted by the reaction temperature and the surfactants. At the range of temperatures from 70 to 80oC, the nano zinc borates were nanoplates of 40-50 nm in thickness. The nano zinc borates grew out of the surface to form nanorods at 90oC and nanowhiskers at 100oC. The nano zinc borates modified with surfactants tended to form larger and thinner plate-like nanoparticles. In the presence of Tween 80, petal-like nano zinc borates were achieved. The petal-like nano zinc borates showed good flame retardant synergistic effects with red phosphorus and expandable graphite on high-density polyethylene matrix. Additionally, the nano zinc borates nanopetals significantly improved the mechanical properties of red phosphorus/expandable graphite/high-density polyethylene composites.