Low-density Polyethylene Composites Research Articles

Potentialities of cellulose nanofibers (CNFs) in low density polyethylene (LDPE) composites

Potentialities of cellulose nanofibers (CNFs) in low density polyethylene (LDPE) composites

Effect of Different Compatibilizers on the Properties of Green Low-Density Polyethylene Composites Reinforced with Bambusa Vulgaris Bamboo Fibers.

Low-density green polyethylene (LDGPE) composites reinforced with 5 wt% of bamboo fiber and 3 wt% of a compatibilizing agent (polyethylene grafted with maleic anhydride and tannin) were processed through extrusion and injection molding. Bamboo fiber, Bambusa Vulgaris, was characterized using Fourier-transform infrared spectroscopy (FTIR). The molded specimens were analyzed for their thermal, mechanical, and morphological properties. The estimated concentration was chosen to provide the best mechanical strength to the material studied. FTIR analysis of the fibers revealed the presence of groups characteristic of bamboo fiber and tannin. Differential scanning calorimetry revealed that both compatibilizing agents increased the matrix's degree of crystallinity. However, scanning electron microscopy (SEM) showed that, despite the presence of compatibilizing agents, there was no significant improvement in adhesion between the bamboo fibers and LDGPE.

DC assisted electric field on the improvement of the nonlinear electrical conductivity of SiC/LDPE field grading composites

Nonlinear resistive field grading material presents nonlinear electrical conductivity, and self-homogenizes the electric field distribution. The nonlinear conductivity is closely associated to the filler distribution, which can be modulated by the electric field assist during the material preparation. In this paper, the effects of the direct current (DC) electric field assist on the filler distribution and nonlinear conductivity of the nonlinear resistive field grading materials were studied for the first time. The silicon carbide (SiC)/low-density polyethylene (LDPE) composites were prepared under different DC assisted electric field. The composites’ microstructure, dielectric spectra and DC conductivity were characterized, respectively. Results illustrate that the DC electric field assist leads to the gradient distribution of SiC filler in the matrix, and also contributes to the SiC particles’ chains. Compared with the untreated SiC/LDPE composite, the electric-field assisted composites show more distinct nonlinear conductivity characteristics when the DC assisted electric field exceeds 0.3 kV mm−1, which is attributed to the percolation phenomenon of SiC particles. This work is helpful to design the dielectric functionally graded materials, and to self-homogenize the electric field distribution in power apparatus and electronic devices.

Lead sulfide quantum dot-linear low-density polyethylene composites for near-infrared Mini-LEDs

Lead sulfide quantum dots (QDs), presenting near-infrared (NIR) emissions, have gained extensive interest within the realm of NIR light-emitting diodes (LEDs). However, the intricate surface defect passivation poses a major impediment that curbs broader applications of PbS QDs. To address it, we introduce linear low-density polyethylene (LLDPE) as a facilitating agent for the aggregation of PbS QDs, aiming to improve their optical properties by harnessing a stress-inducing effect. Compared to the bare PbS QDs that are luminescence silent, the PbS aggregates formed with the addition of LLDPE show a notable photoluminescence quantum yield (PLQY) as high as 20.7 %. Moreover, the presence of LLDPE mitigates the oxidative degradation of lead ions on the PbS QD surface, thereby enhancing the stability of the PbS QDs through steric hindrance. Near-infrared nini-LEDs are demonstrated by combining the PbS QD/LLDPE composites with blue mini-LED chips, which show an emission maximum of 1517.9 nm, a full width at half maximum (FWHM) of 297.6 nm and an energy conversion efficiency (ECE) of 14.6 %. The proposed method opens up new avenues for enhancing the optical properties of PbS QDs without using traditional passivation procedures.

Barium titanate exposure on metallographic and mechanical performance of coir fiber made low‐density polyethylene composite

AbstractTechnological growth and biodegradable waste natural fibers are significant choices in polymer matrix composite preparation because of their distinct qualities from monopoly matrix. During the fabrication process, the natural fiber faces poor compatibility and lack of adhesive behavior, resulting in reduced tensile strength and stiffness of the composite. The theme of the research is expanding the mechanical behavior of low‐density polyethylene (LDPE) composite by the exposure of sodium hydroxide‐treated coir fiber (CF) and barium titanate (BaTiO3) through an injection molding route. Influences of CF and BaTiO3 on metallographic, tensile, flexural, and impact strength and microhardness of LDPE composite are evaluated, and its outcomes are compared with mono LDPE. The surface morphology of the developed composite is exposed to homogenous dispersion of BaTiO3 with effective adhesive bonding with CF, which facilitates superior mechanical properties. The LDPE hybrid composite consists of 30 wt% CF and 2.5 wt% of BaTiO3 and is exploited about 69 ± 1.5 MPa of tensile strength, 54 ± 0.5 MPa of flexural strength, 4.9 ± 0.01 J of impact energy, and 31 ± 1.5HV of microhardness, this is greater than the mono LDPE (unreinforced). The enriched LDPE hybrid composite is suggested for automotive dashboard applications.

Synthesis and Behavior Study of Basalt Fiber-Made Low-Density Polyethylene Composites Via Injection Mold

Synthesis and Behavior Study of Basalt Fiber-Made Low-Density Polyethylene Composites Via Injection Mold

Preparation and properties of multilayer core-shell structure ammonium polyphosphate synergistic with THEIC for flame retardant LDPE

In this paper, a new type of highly efficient intumescent flame-retardant low-density polyethylene composite was prepared using two key technologies, namely, microencapsulation encapsulation technology and novel carbon formation technology. Precisely, β-cyclodextrin encapsulated modified ammonium polyphosphate@melamine formaldehyde resin (β-CDMCAPP@MF) was prepared by using Si-IFR synergistic flame retardant effect combined with the gel-solution method, and then flame retardant low-density polyethylene (LDPE) was prepared by compounding with tris-(2-hydroxyethyl) isocyanate (THEIC). The results showed that β-CDMCAPP@MF was modified with MF, β-CD, and silica coating. This modification resulted in excellent hydrophobicity and good compatibility with LDPE. The addition of IFR containing β-CDMCAPP@MF significantly improved the flame retardancy of the LDPE composites. Specifically, when 30 wt% of β-CDMCAPP@MF was added, the ultimate oxygen index of the composites reached 24.7 %, and V-0 grade and the tensile strength went 11.41 MPa. Compared with IFR/LDPE with the same proportion of MF@MCAPP and β-CD@MCAPP, the ultimate oxygen indices were increased by 9.72 % and 12.15 %, respectively. The introduction of THEIC into the flame retardant system resulted in a LOI value of 36.5 % and an FRI value of 2.523, which is 32.33 % higher than that of the composites containing 30 wt% of the flame retardant system (without THEIC). Cone calorimetry test results showed that introducing β-CDMCAPP@MF and THEIC significantly improved the smoke emission.

Polymer Composites of Low-Density Polyethylene (LDPE) with Elongated Hematite (α-Fe2O3) Particles of Different Shapes

Due to the intensive search for new types of advanced polymer materials for targeted applications, this work offers insight into the properties of low-density polyethylene/hematite composites. The specific feature of this study lies in the use of elongated hematite particles of different shapes. Uniform ellipsoid-, peanut- and rod-shaped hematite particles were hydrothermally synthesized and incorporated into the polymer matrix of low-density polyethylene (LDPE). LDPE/hematite composites are prepared by melt mixing. Hematite particles are characterized by scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD). The pure LDPE polymer and LDPE/hematite composites were studied by FT-IR and UV-Vis-NIR spectroscopy and by thermogravimetric analysis (TGA). The determination of the mechanical and barrier properties was also carried out. The obtained results indicate the influence of the elongated particles on the improvement of LDPE properties. An increase in thermal stability and UV-absorption was observed as well as the improvement of mechanical and barrier properties. The improvement of the composites’ properties in comparison to the pure LDPE is especially visible in the composites prepared with low content of hematite (0.25%). LDPE/hematite composites have promising characteristics for application as packaging materials with enhanced mechanical, thermal and barrier properties as well as UV-protective materials.

Effect of lignocellulosic corn stalk on mechanical, physical, and thermal properties of injection moulded low density polyethylene composites: An approach towards a circular economy

Escalating concern over global warming, which is mostly associated with deforestation, has led to the development of new classes of materials that can replace wood and better utilise natural resources. Presently, waste is a significant factor in recycling. In this regard, one of the leading contributors to waste is agricultural waste, which includes dried branches, leaves of trees, plants, and other organic materials. In the current study, waste from corn agriculture was utilised as a potential reinforcement for the fabrication of corn stalk-low density polyethylene (CS-LDPE) composites via an injection moulding technique at 170 °C. The different parameters were assessed to develop composites using CS, including physico-chemical, macromolecular, mineralogical, elemental, and morphological analysis. The amount of corn stalk (CS) was varied from 10 to 50 wt% with respect to the polymer. The mechanical, physical and thermal performance of the composites was examined. The density and water absorption of the composites were found to remain within the ranges of 1.00–1.11 g/cm3 and 0.22–1.01 %, respectively, whereas these parameters increased as the proportion of CS increased. The thermal conductivity decreases with the addition of CS from 0.36964 ± 0.020 to 0.22388 ± 0.002 W/mK. It was observed that adding CS to the composites increased their tensile and flexural properties, but decreased their impact strength. The maximum flexural strength of 14.40 ± 1.558 MPa, flexural modulus of 752.53 ± 180.409 MPa, tensile strength of 10.49 ± 0.946 MPa and tensile modulus of 539.79 ± 91.044 MPa were observed with a 50 % CS content. The results suggest that these materials have considerable potential to serve as a cost-effective substitute for the conventional lignocellulosic fillers in the manufacturing of wood-plastic composites.

Utilization of Ananas comosus Crown Residue Husk as a Sustainable Strength Additive for EPR/LDPE Blend Composites.

The utilization of waste generated by natural resources is a crucial problem nowadays. The current study describes the utilization of pineapple (Ananas comosus) crown residue husk (PCRh) as a strength additive for low-density polyethylene (LDPE) and ethylene propylene rubber (EPR) composites. The blend composites with 30% husk, 10 wt % EPR, and 60% LDPE content showed much better mechanical properties, such as tensile strength and flexural properties, than pristine LDPE and its binary composite with 10 wt % EPR. The high tensile strength (∼19.28 MPa) and tensile modulus (522.97 MPa) were obtained for the composite consisting of 30 wt % PCRh in the basic polymer matrix. Similarly, the highest flexural strength (∼18.09 MPa) and modulus (∼790.29 MPa) were recorded for the same composition. The incorporation of PCRh with LDPE and EPR was further characterized by attenuated total reflection-Fourier transform infrared, differential scanning calorimetry, field emission scanning electron microscopy, dynamic mechanical analysis, and a universal testing machine to evaluate its impact on various properties.

Ecofriendly Biochar as a Low-Cost Solid Lubricating Filler for LDPE Sustainable Biocomposites: Thermal, Mechanical, and Tribological Characterization

The potential of ecofriendly biochar, a carbon-rich byproduct of biomass pyrolysis, as a low-cost solid lubricating filler for low-density polyethylene (LDPE) sustainable biocomposites is investigated in this work. Tensile strength, hardness, thermogravimetric analysis (TGA), melting flow index (MFI), tensile test, flexural test, and frictional tests were used to characterize the biocomposites’ mechanical, thermal, and tribological properties. Energy-dispersive X-ray spectroscopy (EDS) was used to assess the chemical composition of the biochar, while field-emission scanning electron microscopy (FESEM) was used to capture the biochar morphology. The results showed that the incorporation of biochar in LDPE matrix increased the mechanical characteristics of the biocomposites and resulted in a significant increase in tensile strength, flexural strength, and hardness. More specifically, the LDPE+10 wt% composite outperformed the pure LDPE matrix by 1.9% in tensile strength and 47% in flexural strength. Furthermore, integrating biochar into LDPE composites enhances thermal stability, lowers the melt flow index (MFI), and boosts the hardness by 24.3% for the composite with 10% biochar content. Furthermore, biochar improves wear resistance and durability, with the LDPE10 composite exhibiting a friction coefficient that is 56.3% lower than pure LDPE. These findings indicate that biochar is a viable, cost-effective, and environmentally friendly filler for improving the performance of LDPE-based biocomposites for many varieties of applications.

Study on the effect of novel intumescent flame retardant composed of β-cyclodextrin modified ammonium polyphosphate and THEIC on the flame retardancy of LDPE composites

Enhancing polymer flame retardancy is crucial for lowering combustion-related exothermic heat and flue gas production. β-cyclodextrin microencapsulated ammonium polyphosphate (β-CD@APP) were synthesis through in-situ polymerization and combined with 1, 3, 5-tris (2-hydroxyethyl) isocyanurate (THEIC) as a novel intumescent flame retardant (IFR) to enhance the flame retardancy of low density polyethylene (LDPE). The results showed that APP's hydrophobic characteristic increased, which enhanced its polymer dispersibility. Compared with LDPE, the LOI value of β-CD@APP/THEIC/LDPE (LDPE5) was enhanced from 17.5% to 28.7% and the composites could meet the UL-94 V-0 standard. Smoke volume and thermal decomposition rate were reduced. Furthermore, a stable char layer was found, which can be seen from the SEM of the char slag and the Raman results. According to the above results, the thermal decomposition and possible mechanism of flame retardants in LDPE composites during combustion were studied.

The evaluation of waste engine oil/old newspaper in recycled low density polyethylene composites

AbstractThe study investigates changes in the mechanical, thermal, morphological and physical properties of recycled low density polyethylene (LDPE) composites made with percentages (10 wt%, 20 wt%, 30 wt.%) of old newspaper fiber (ONF) and waste engine oil (WEO) (1 wt.%). The composites were manufactured by a single screw extruder. Adding WEO up to 20 wt% of ONF had a positive effect on the flexural properties, while the incorporation of WEO up to 10 wt % of ONF showed an affirmative effect on the tensile properties of the composites. The highest flexural strength was achieved in A3 (13.19 MPa) and B3 (12.3 MPa) samples for ONF added composites and ONF/WEO composites, respectively. Adding to the WEO decreased the water absorption values of the recycled low density polyethylene composites. Differential scanning calorimetry analysis showed that the addition of 1% WEO, the crystallinity of the composites decreased to about 30%. In the light of the results, the WEO could be successfully used with old newspaper in a polyethylene matrix.Highlights The highest tensile strength was achieved in the B3 sample (with WEO). The highest flexural strength was achieved in the B3 sample (with WEO). The highest tensile was obtained from the A3 sample (without WEO). The highest flexural strength was obtained from the A3 sample (without WEO). The crystallinity of the composites decreased to about 30%.

Antibacterial and Biocompatible Polyethylene Composites with Hybrid Clay Nanofillers.

Low-density polyethylene is one of the basic polymers used in medicine for a variety of purposes; so, the relevant improvements in functional properties are discussed here, making it safer to use as devices or implants during surgery or injury. The objective of the laboratory-prepared material was to study the antimicrobial and biocompatible properties of low-density polyethylene composites with 3 wt. % hybrid nanoclay filler. We found that the antimicrobial activity was mainly related to the filler, i.e., the hybrid type, where inorganic clay minerals, vermiculite or montmorillonite, were intercalated with organic chlorhexidine diacetate and subsequently decorated with Ca-deficient hydroxyapatite. After fusion of the hybrid nanofiller with polyethylene, intense exfoliation of the clay layers occurred. This phenomenon was confirmed by the analysis of the X-ray diffraction patterns of the composite, where the original basal peak of the clays decreased or completely disappeared, and the optimal distribution of the filler was observed using the transmission mode of light microscopy. Functional property testing showed that the composites have good antibacterial activity against Staphylococcus aureus, and the biocompatibility prediction demonstrated the formation of Ca- and P-containing particles through an in vitro experiment, thus applicable for medical use.

Effect of the melt flow index of compatibilizer on the melt processing and properties of highly filled magnesium hydroxide/linear low density polyethylene composites

AbstractThe application of highly filled composites is limited by their poor processing and rheological properties due to the high loading of fillers. One possible solution to this problem is to use maleic anhydride grafted polypropylene (MAPP) with high melt index as compatibilizer and lubricant. Herein, magnesium hydroxide (MH)/linear low‐density polyethylene (LLDPE) composites with 60 wt% of MH were prepared using MAPP with three different melt flow indexes (MFI). The equilibrium torque and melt flow index tests show that the addition of MAPP with high MFI significantly improves the processability and flowability of MH/MAPP/LLDPE composites. The rheological studies show that it also leads to a substantial reduction in the viscosity and therefore MH/MAPP/LLDPE composites exhibit more solid‐like responses. The scanning electron microscopy shows that a transition layer is formed at the MH‐LLDPE interface. The flame retardancy test shows that the addition of MAPP slightly reduces the flame retardancy of the composites as evidenced by the reduced limiting oxygen index and increased total heat release. Cone calorimeter test shows that the simultaneous addition of MH and MAPP has a synergistic smoke suppression effect.

The effect of coated calcium carbonate using stearic acid on the recovered carbon black masterbatch in low-density polyethylene composites

Abstract This research focuses on recycling rubber tire waste through pyrolysis to produce recovered carbon black (rCB). The rCB is combined with recycled low-density polyethylene (rLDPE), calcium carbonate (CaCO3), fatty acid, metallic stearate, and polyethylene (PE) wax to create an rCB masterbatch for household packaging. Surface modification of CaCO3 particles using stearic acid improves the compatibility with LDPE. The study investigates mechanical properties, morphology, melt flow index (MFI), X-ray diffraction, and thermogravimetric analysis in three systems: uncoated, coated, and a hybrid combination of coated and uncoated CaCO3 in LDPE/rCB masterbatch composites. The coated system demonstrates higher mechanical properties and improved compatibility between CaCO3 and LDPE. All three systems exhibit enhanced thermal stability and MFI compared to virgin LDPE, with the coated system showing the most significant improvement. The study showcases the potential of LDPE/rCB masterbatch composites for household packaging, with the coated system displaying the optimum performance across various characteristics.

Preparation and properties of modified ammonium polyphosphate synergistic with tris(2-hydroxyethyl) isocynurate for flame-retardant LDPE

Abstract UF-SiAPP was prepared by modifying ammonium polyphosphate with the urea formaldehyde resin (UF), tetraethylorthosilicate (TEOS), and vinyltriethoxysilane (A-151). Moreover, a new intumescent flame retardant (IFR) used for low density polyethylene (LDPE) flame retardant was obtained by mixing UF-SiAPP with tris(2-hydroxyethyl) isocynurate (THEIC). The structure, morphology, and mechanical properties of flame retardants and LDPE composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, TG, and universal material testing machines. Furthermore, the flame-retardant properties of LDPE composites were comprehensively investigated by limiting oxygen index (LOI), UL-94, and cone calorimetry tests. The results show that UF-SiAPP exhibits excellent hydrophobic properties and good compatibility with LDPE after being modified by UF, TEOS, and A-151. And the flame-retardant properties of LDPE composites are significantly improved by adding IFR-containing UF-SiAPP. Especially, the LDPE composites attained the LOI value of 30.5% and reached the V-0 level after introducing 20.0 wt% UF-SiAPP and 10.0 wt% THEIC. And the tensile strength reached 13.55 MPa, which was 10.33% higher than that of LDPE/IFR with UF-APP and 13.21% higher than that of LDPE/IFR without THEIC in the same proportion. The smoke density tests demonstrate that the addition of UF-SiAPP not only effectively improves the residual carbon content and thermal stability of LDPE composites but also significantly reduces smoke emissions.

Effect of Functionalized Polyethylene Wax on the Melt Processing and Properties of Highly Filled Magnesium Hydroxide/Linear Low-Density Polyethylene Composites.

The poor processing and rheological properties of highly filled composites caused by the high loading of fillers can be improved with the use of maleic anhydride grafted polyethylene wax (PEWM) as compatibilizer and lubricant. In this study, two PEWMs with different molecular weights were synthesized by melt grafting, and their compositions and grafting degrees were characterized by Fourier transform infrared (FTIR) spectroscopy and acid-base titration. Subsequently, magnesium hydroxide (MH)/linear low-density polyethylene (LLDPE) composites with 60 wt% of MH were prepared using polyethylene wax (PEW) and PEWM, respectively. The equilibrium torque and melt flow index tests indicate that the processability and fluidity of MH/MAPP/LLDPE composites are significantly improved with the addition of PEWM. The addition of PEWM with a lower molecular weight leads to a substantial reduction in viscosity. The mechanical properties are also increased. The limiting oxygen index (LOI) test and cone calorimeter test (CCT) show that both PEW and PEWM have adverse effects on flame retardancy. This study provides a strategy to simultaneously improve the processability and mechanical properties of highly filled composites.

Development of Graphene Oxide/Polyethylene to enhance mechanical properties through melt mixing technique

Graphene Oxide (GO) was added to Low-Density Polyethylene (LDPE) to test the mechanical properties of the compound. Compared to other types of polyethylene, LDPE provides a good balance of mechanical properties and processability, which leads to its being chosen as the research’s matrix material. This experiment aims to prepare LDPE/GO through melt mixing technique and analyse mechanical properties of tensile strength/tensile elongation of LDPE/GO composite based on GO concentration (0, 0.5, 1.0 and 1.5 wt%). The compounding of LDPE/GO was blended using a five-stage twin-screw extruder under specific conditions before going through the moulding process at melting temperature. The composites were cut according to ASTM D638 specimen dimension. The tensile properties of LDPE composites were filled separately with different weight fractions of GO at a 50 mm/min rate. It was found that the values of Young’s modulus of the composites increased, but the values of the tensile elongation at break decreased with increasing the GO weight fraction. The relatively big interfacial area and excellent interfacial adhesion between the matrix and the GO may be responsible for the composites’ reinforcement. This study provided a basis for further development of GO-reinforced LDPE composites with desirable mechanical performance and good damage behaviour.

Effects of Maleic Anhydride-Grafted Polyethylene on the Properties of Artificial Marble Waste Powder/Linear Low-Density Polyethylene Composites with Ultra-High Filling Content.

The need to reach carbon neutrality as soon as possible has made the use of recycled materials widespread. However, the treatment of artificial marble waste powder (AMWP) containing unsaturated polyester is a very challenging task. This task can be accomplished by converting AMWP into new plastic composites. Such conversion is a cost-effective and eco-friendly way to recycle industrial waste. However, the lack of mechanical strength in composites and the low filling content of AMWP have been major obstacles to its practical application in structural and technical buildings. In this study, a composite of AMWP/linear low-density polyethylene (LLDPE) filled with a 70 wt% AMWP content was fabricated using maleic anhydride-grafted polyethylene as a compatibilizer (MAPE). The mechanical strength of the prepared composites is excellent (tensile strength ~18.45 MPa, impact strength ~51.6 kJ/m2), making them appropriate as useful building materials. Additionally, laser particle size analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermogravimetric analysis were used to examine the effects of maleic anhydride-grafted polyethylene on the mechanical properties of AMWP/LLDPE composites and its mechanism of action. Overall, this study offers a practical method for the low-cost recycling of industrial waste into high-performance composites.