Maleated Polyethylene Research Articles

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.

Characterization of Posidonia oceanica Fibers High-Density Polyethylene Composites: Reinforcing Potential and Effect of Coupling Agent

This study investigated the influence of fiber loading and maleated polyethylene (MAPE) coupling agent on the structural, thermal, mechanical, morphological properties, and torque rheology of high-density polyethylene (HDPE) reinforced with Posidonia oceanica fiber (POF) composites. HDPE/POF composites, both with and without MAPE, were manufactured using a two-step process: composite pellets extrusion, followed by test samples injection molding with various POF loadings (0, 20, 30, and 40 wt%). HDPE/POF composites reinforced with higher loading of POF (40 wt%) exhibit superior stiffness, better crystallinity, and higher stabilized torque and mechanical energy (Em) compared to other composite formulations. Therefore, varying the POF loading leads to extrusion and injection processing variations. Furthermore, the coupling agent significantly enhances the tensile strength, ductility, impact strength, crystallinity, stabilized torque, and Em of the HDPE/POF composite. This improvement is due to the enhanced interfacial adhesion between the POF and the HDPE matrix with the addition of the MAPE, as supported by the Scanning Electron Microscopy (SEM) micrographs.

High‐performance wood‐reinforced crosslinked high‐density polyethylene composites

AbstractThis paper presents a comprehensive investigation into the manufacturing of high‐performance wood‐crosslinked high‐density polyethylene composites (WxHDPEC). In particular, the effect of maleated polyethylene (MAPE) treatment and concentration (0–50 wt%) of maple wood fibers is investigated. The samples were produced via dry‐blending followed by compression molding and a set of characterization was performed including chemical, morphological, mechanical, thermal, and physical properties. The gel content was found to increase with increasing wood fiber content, while the surface modification significantly improved the tensile strength (11%), tensile modulus (298%), flexural strength (138%), and flexural modulus (81%). Thermal analyses also showed improved thermal stability and higher thermal resistance for the treated composites. Finally, the Shore D hardness increased by 11.0 (from 61.5 to 72.5) and 12.1 (from 61.5 to 73.6) points, while the Shore A hardness increased by 7.5 (from 91.5 to 99.0) and 8.1 (from 91.5 to 99.6) points for the untreated and treated composites, respectively. These improvements are attributed to effective adhesion between MAPE‐treated wood fibers and the xHDPE matrix. The findings not only advance our understanding of these complex materials but also provide alternatives for various applications from construction to automotive engineering.Highlights High‐performance wood‐reinforced crosslinked high‐density polyethylene was produced. The effect of maleated polyethylene (MAPE) treatment and maple wood fibers was studied. Higher crosslink density in MAPE‐treated wood‐xHDPE was obtained. Wood‐crosslinked high‐density polyethylene composites have better properties.

Properties of polylactic acid blends with potato thermoplastic starch using maleated polyethylene as a compatibilizer

AbstractIn this study, blends of polylactic acid (PLA) and potato thermoplastic starch (TPS) with and without maleated polyethylene (MAPE) as a compatibilizer were prepared by twin‐screw extrusion followed by compression molding. Different formulations were proposed based on an experimental design to determine the concentration of each component for a specific range of composition: 49%–79% of PLA, 20%–50% of TPS, and 0.5%–2% of MAPE. As a first step, the mechanical properties (tensile, flexural, and impact) were used to determine the best performance of these formulations. Then, the mechanical results were used in an objective function to maximize the blends' properties compared to virgin PLA. The optimal formulation was found to be 67.5% PLA, 32.0% TPS, and 0.5% MAPE. Selected formulations were characterized for their thermal, morphological, and water absorption properties. The results show the possibility of producing sustainable polymers for single‐use applications.

Mechanical, Thermal Properties of Virgin, Recycled and Mixed High-Density Polyethylene Matrices and Wood Plastic Composites with Plywood Sanding Dust

Virgin high-density polyethylene (vHDPE), recycled (rHDPE), and mixed vHDPE/rHDPE matrices and wood plastic composites based on these mixtures + 50 wt.% of plywood sanding dust (PSD) and 3 wt.% coupling agent maleated polyethylene (MAPE) physical-mechanical properties (tensile, flexural strength and modulus, impact strength, and microhardness) were investigated. It was observed that all defined properties depend on the content of rHDPE in the pure polymer matrix and corresponding WPCs. Tensile strength and modulus decreased a bit, but flexural modulus actually had no changes. At the same time, a decrease in impact strength and a significant increase (up to 2 times) in microhardness are observed. From all the investigated matrices, the most perspective seems to be the matrix with a vHDPE/rHDPE ratio of 75/25, whose mechanical properties are acceptable for the preparation of the WPCs based on plywood sanding dust. The compatibilization possibilities tests of different mixed matrices done by the DSC method in the air showed that the mixed vHDPE/rHDPE compositions compatibility is sufficiently good at different proportions. For all mixed matrices, only one relatively symmetric band with one peak of melting was observed. Differential scanning calorimetry (DSC) tests in an inert environment showed that during the first heating cycle, HDPE components are only partially compatible (two peaks of melting temperatures are possible to fix). On the contrary, after the cooling and crystallization processes, during the second heating of the same sample, these two bands completely merge, and like in the air, only one maximum melting temperature peak was observed. The values of thermal oxidation temperature and melting temperature are the highest for virgin vHDPE but the lowest for rHDPE. The values of all corresponding parameters of mixed matrices reduce proportionally with an increase in rHDPE content in the mixtures.

Preparation of Polyethylene/α-Zirconium Phosphate Nanocomposites via a Well-Controlled Polyethylene-Grafted Interface.

It is a daunting task to prepare polyolefin nanocomposites that contain well-exfoliated nanoplatelets due to the nonpolar and high crystallinity nature of polyolefins. In this research, a robust approach was developed to prepare polyethylene (PE) nanocomposites by grafting maleated polyethylene (MPE) onto pre-exfoliated α-zirconium phosphate (ZrP) nanoplatelets via a simple amine-anhydride reaction to form ZrP-g-MPE. Several variables, including maleic anhydride (MA) content, MPE graft density, MPE molecular weight, and PE matrix crystallinity, were investigated to determine how they influence ZrP-g-MPE dispersion in PE. It was found that grafted PE has a different morphology and that the long PE brushes with medium graft density on ZrP can achieve sufficient chain entanglement and cocrystallization with PE matrix to stabilize and maintain ZrP-g-MPE dispersion after solution or melt mixing. This leads to enhanced Young's modulus, yield stress, and ductility. The structure-property relationship of PE/ZrP-g-MPE nanocomposites and usefulness of this study for the preparation of high-performance polyolefin nanocomposites are discussed.

An Enhancement of Compositional Stability of Phase Change Materials by Lamination with Aluminum Sheet

The wax leakage from shape-stabilized phase change materials (SSPCMs) is a limitation because it reduces their functionality. In this work, an enhancement of the compositional stability of SSPCMs formed by high-density polyethylene (HDPE) and paraffin wax blends through a lamination by aluminum (Al) foil was studied. The materials’ thermal conductivity was enhanced by adding expanded graphite (EG). The lamination of SSPCMs is the simplest method of reducing leakage, but it suffers from poor adhesion between polymer-based blends and protecting layers. The improved adhesion between SSPCMs and Al foil was achieved by adding 2 wt.% of maleated polyethylene (PE) acting as an adhesion promoter into SSPCMs or by plasma treatment of both SSPCMs and Al surfaces. Microscopic, spectroscopic, and optical techniques were used to analyze the surface and adhesion properties of SSPCMs. The peel resistance of SSPCMs after plasma treatment or modification by maleated PE increased from 2.2 N/m to 7.2 N/m or 55.1 N/m, respectively. The wax leakage from the treated or modified SSPCMs was suppressed significantly. The plasma-treated or maleated PE-modified SSPCMs showed leakage of 0.5 wt.% or 0.2 wt.%, respectively, after three days of leakage test. It indicates a good potential of this treatment/modification for industrially applied SSPCMs.

An Adhesion Improvement of Low-Density Polyethylene to Aluminum through Modification with Functionalized Polymers.

An interfacial adhesion improvement between low-density polyethylene (LDPE) and aluminum (Al) foil is an important challenge in designing multilayered packaging (TetraPak packaging type) due to insufficient inherent adhesion between both untreated materials. Therefore, extra adhesive layers are often used. The hydrophobic character of LDPE is responsible for poor adhesion to Al and can result in delamination. This study deals with the comparative study of the bulk modification of LDPE with various commercially available adhesive promoters with different chemical compositions to increase LDPE's adhesive characteristics and ensure good adhesion in LDPE/Al laminates. A copolymer of ethylene and methacrylic acid; a terpolymer of ethylene, maleic anhydride, and acrylic ester; or maleated polyethylene (PE) were used as adhesive promoters, and their effect on adhesion improvement of LDPE to Al was investigated. The best adhesion improvement was observed in LDPE-modified samples with maleated PE, while 0.1 wt.% additive content significantly increased peel resistance (from zero to 105 N/m). An additional increase in additive content (0.5 wt.%) in LDPE led to stronger adhesion forces than the cohesion forces in Al foil. Adding 0.5 wt.% of maleated PE into LDPE improved the LDPE/Al laminates' adhesion and can be applied in multilayered lamination applications.

Development of natural fiber reinforced thermoplastic bonded hybrid wood veneer composite

This study aimed at preparing thermoplastic based hybrid wood veneer composite panels in which bamboo fiber reinforced thermoplastic (BPC) was used in granular form as one component and Melia dubia wood veneers as the second component. BPC was prepared using twin screw extruder and maleated polyethylene/ maleated polypropylene as a coupling agent. The effect of polymer type i.e., polypropylene (PP), high density polyethylene (HDPE) and poly butylene adipate-co-terephthalate (PBAT) and bamboo fiber content (10%, 30%, and 50%) on physical, mechanical and thermal properties of Melia dubia plywood has been investigated. Plywood prepared with BPC exhibited superior mechanical properties as compared to pure polymer irrespective of polymer type. The improvement in flexural strength at 30% bamboo content was 14.6%, 17.6% and 38% for PP, HDPE and PBAT based BPC, respectively. Volumetric swelling in panels on water absorption was not influenced by the presence of bamboo fibers in the polymer. The improvement in mechanical properties of BPC bonded plywood was due to manifestation of an improved interfacial adhesion between BPC and wood veneers via coupling agent. SEM images revealed pertinent bonding between BPC and wood veneers in the form of mechanical interlocking.

Influence of pretreated sugarcane bagasse fiber by steam explosion, soaking with caustic soda, and addition of coupling agent into polylactic acid biocomposites

Biocomposites containing natural fibers waste have gained the attention of researchers due to their biodegradability and suitability for several applications in different industries. In this study, sugarcane bagasse fibers waste was treated by digestion with NaOH and steam explosion to the previous soaking with NaOH, and their impregnation with 1% maleated polyethylene was used as reinforcement in poly (lactic acid) matrix composites. Surface morphological changes were observed with scanning electron microscopy due to fiber treatment/MAPE in the PLA matrix. The biocomposites with MAPE improved Young’s modulus, but the strength tensile was reduced. Flexural modulus of biocomposites shows a considerable increase with MAPE, for biocomposites of 10% and 20% of bagasse the values are circa 8000 MPa regarding the 3500 MPa from PLA. These increases in the properties are ascribed to the improved interfacial interaction of the modified sugarcane bagasse fibers into the PLA. The analysis of TGA shows that incorporation of fiber with and without treatment and MAPE improved the thermal stability. By adding fiber into the biocomposites, the loss modulus peak becomes wider, this means that adhesion of the matrix and the fiber were improved. The X-ray diffraction graph shows an increase in the crystallinity of the biocomposites after the treatment and the addition of MAPE compared to the matrix of PLA.

Multifunctional polyethylene nanocomposites based on polyethylene-grafted α-zirconium phosphate nanoplatelets

Multifunctional polymer nanocomposites are gaining significant interest due to the ever-increasing application demands for high performance polymers. In this study, a nanoplatelet functionalization methodology was developed to achieve its well exfoliation and multifunctionality in polyethylene (PE). In addition to the commonly known benefits of the improved modulus and barrier properties, the nanoplatelets can be grafted with fire retarding molecules to further improve flame retardancy of PE. Specifically, PE nanocomposites consisting of well-exfoliated α-zirconium phosphate (ZrP) was prepared via grafting of maleated PE (MPE) on ZrP (ZrP-MPE). The exfoliated ZrP-MPE was further covalently modified with additional phosphorous-based functional group to achieve improved flame retardancy. The grafted MPE on ZrP can co-crystallize with PE matrix to stabilize ZrP exfoliation in PE matrix. The observed synergistic flame retardation effect is attributed to the barrier effect of the well-exfoliated ZrP and gas phase radical trapping by the phosphorous-based functional group on ZrP surface. The usefulness of the present study for preparation of multifunctional polymer nanocomposites is discussed.

Recycled HDPE/Natural Fiber Composites Modified with Waste Tire Rubber: A Comparison between Injection and Compression Molding.

With the objective of turning wastes into added-value materials, sustainable and fully recycled wood-plastic composites were reinforced by waste tire rubber particles to show balanced properties and potentially low-cost materials. Recycled high density polyethylene (rHDPE) was compounded (melt extrusion) with flax fiber (FF) and waste regenerated tire rubber (RR) to investigate the effect of mixing ratio, coupling agent (maleated polyethylene, MAPE) and molding process (injection and compression molding) on the properties of hybrid composites. In particular, a complete set of characterization was performed including thermal stability, phase morphology and mechanical properties in terms of tension, flexion and impact, as well as hardness and density. Adding 40 wt.% of flax fibers (FF) increased the tensile (17%) and flexural (15%) modulus of rHDPE, while the impact strength decreased by 58%. Substitution of FF by waste rubber particles improved by 75% the impact strength due to the elasticity and energy absorption of the rubber phase. The effects of impact modification were more pronounced for rHDPE/(FF/RR) compatibilized with MAPE (10 wt.%) due to highly improved interfacial adhesion and compatibility. The results also suggest that, for a fixed hybrid composition (FF/RR, 25/55 wt.%), the injection molded composites have a more homogenous morphology with a uniform distribution of well embedded reinforcements in the matrix. This better morphology produced higher tensile strain at break (12%) and impact strength (9%) compared to compression molded samples.

Effect of borax-boric acid and ammonium polyphosphate on flame retardancy of natural fiber polyethylene composites

Wood fiber filled high density polyethylene composites (WPCs) were prepared using twin screw extruder and maleated polyethylene as a coupling agent. Bamboo fibers were initially treated with alkali (NaOH), boric acid - borax (Ba-Bx) and borax (Bx). The treated and untreated fibers were used in combination with ammonium polyphosphate (APP) to investigate their synergistic effects on thermal stability, flame retardancy and mechanical properties. Alkali pretreatment (5 % NaOH) of fibers showed significant improvement in performance of APP by increasing thermal stability in WPCs. The derivative thermogravimetric (DTG) results indicate significance of Ba-Bx in promoting char induction at lower temperatures (340 ºC) and thereby, improved the thermal stability in WPCs. Flammability decreased with addition of flame retardant additives. As compared to pure WPCs, composites containing APP 10 % / Ba-Bx 5 % exhibited maximum reduction in average heat release rate (HRR) by 69 %, peak heat release rate (PHRR) by 59 %, total heat released rate (THR) by 48 % and also increased time to ignition (TTI) by 62 %. However, no significant difference was found among the combinations i.e., APP with or without compounds towards reducing the flammability of WPCs. The strength properties also reduced significantly when boron compounds were added along with APP. In general, APP alone (15 %) is enough for imparting thermal stability and flame retardancy in WPCs.

Influence of Viscosity-interface Modifier Interactions on Performance and Processability of Rice Hull PE Composites

Abstract Interface modifiers and viscosity modifiers are added to wood plastic composites to improve interfacial adhesion and processing rate respectively. However, because of the chemically reactive nature of interface modifiers and viscosity modifiers, there is a high possibility of interactions between them, influencing the mechanical properties and processabilty of the composites. To evaluate this point, interactions between three different interface modifiers and a viscosity modifier were investigated in this study. Concurrently, the effectiveness of three different interface modifiers in improving mechanical properties of the composites was also studied. The results indicated that there was a significant improvement in the tensile strength, flexural strength, flexural modulus and impact properties of the composites with all the three maleated polyethylene based coupling agents. Moreover, presence of an amide carboxylic acid based viscosity modifier along with a maleated polyolefin based interface modifier reduced the mechanical properties of the composites as compared with that of the composites having only maleated polyolefin based interface modifiers.

Sustainable Cellulose-Aluminum-Plastic Composites from Beverage Cartons Scraps and Recycled Polyethylene.

The sustainable management of multilayer paper/plastic waste is a technological challenge due to its composite nature. In this paper, a mechanical recycling approach for multilayer cartons (MC) is reported, illustrating the realization of thermoplastic composites based on recycled polyethylene and an amount of milled MC ranging from 20 to 90 wt%. The effect of composition of the composites on the morphology and on thermal, mechanical, and water absorption behavior was investigated and rationalized, demonstrating that above 80 wt% of MC, the fibrous nature of the filler dominates the overall properties of the materials. A maleated polyethylene was also used as a coupling agent and its effectiveness in improving mechanical parameters of composites up to 60 wt% of MC was highlighted.

Effect of Wood Fiber Surface Treatment on the Properties of Recycled HDPE/Maple Fiber Composites

This work reports on the production and characterization of recycled high density polyethylene (R-HDPE) composites reinforced with maple fibers. The composites were produced by a simple dry-blending technique followed by compression molding. Furthermore, a fiber surface treatment was performed using a coupling agent (maleated polyethylene, MAPE) in solution. FTIR, TGA/DTG, and density analyses were performed to confirm any changes in the functional groups on the fiber surface, which was confirmed by SEM-EDS. As expected, the composites based on treated fiber (TC) showed improved properties compared to composites based on untreated fiber (UC). In particular, MAPE was shown to substantially improve the polymer–fiber interface quality, thus leading to better mechanical properties in terms of tensile modulus (23%), flexural modulus (54%), tensile strength (26%), and flexural strength (46%) as compared to the neat matrix. The impact resistance also increased by up to 87% for TC as compared to UC. In addition, the maximum fiber content to produce good parts increased from 15 to 75 wt% when treated fiber was used. These composites can be seen as sustainable materials and possible alternatives for the development of low-cost building/construction/furniture applications.

Effect of Maleated Polyethylene Wax on Mechanical and Rheological Properties of LDPE/Starch Blends

Effect of Maleated Polyethylene Wax on Mechanical and Rheological Properties of LDPE/Starch Blends

Dielectric Properties of Wood-Polymer Composites: Effects of Frequency, Fiber Nature, Proportion, and Chemical Composition

The characterization of the dielectric properties of wood–polymer composites (WPCs) is essential to understand their interaction with electromagnetic fields and evaluate their potential use for new applications. Thus, dielectric spectroscopy monitored the evolution of the dielectric properties of WPCs over a wide frequency range of 1 MHz to 1 GHz. WPCs were prepared using mixtures of different proportions (40%, 50%, and 60%) of wood and bark fibers from various species, high-density polyethylene, and maleated polyethylene (3%) by a two-step process, extrusion and compression molding. Results indicated that wood fibers modify the resistivity of polyethylene at low frequencies but have no effect at microwave frequencies. Increasing the fiber content increases the composites’ dielectric properties. The fibers’ cellulose content explains the variation in the dielectric properties of composites reinforced with fibers from different wood species. Indeed, composites with high cellulose content show higher dielectric constants.

Effect of surface modification and fiber content on the mechanical performance of compression molded polyethylene‐maple composites

AbstractWith the objective of producing more sustainable materials, wood‐plastic composites were produced using linear low density polyethylene and a wide range of maple wood fiber content (up to 80% wt). This was possible by using a simple dry‐blending of the component in a powder form and compression molding. In particular, the effect of different surface treatments (mercerization, maleated polyethylene [MAPE], and their combination) on the morphology and mechanical performance of these composites was studied. The results show that all the surface treatments investigated were able to improve the fiber‐matrix adhesion, leading to better composite homogeneity, and higher mechanical properties. Furthermore, it was possible to increase the amount of wood that can be introduced in the composites compared to untreated fibers. In our case, up to 80% wt of maple fibers were easily processed generating significant improvements in moduli (367%) and strength (50%), especially when a combination of alkali‐MAPE treatment was performed. This simple processing of the composites is interesting to produce different parts size and geometry with limited degradation since no melt compounding is performed. The work also represents a way to produce sustainable, economic, and lightweight composites with improved properties using a high content of renewable filler.

Properties of Nanocomposites of High-Pressure Polyethylene with Metal-Containing Nanofillers

The effect of nanofiller (NF) additives containing copper oxide nanoparticles (NPs) stabilized by a polymer matrix of maleated polyethylene (MAPE), obtained by the mechanochemical method, on the properties of composites based on high-pressure polyethylene (LDPE) has been investigated by X-ray diffraction (XRD) and thermographic (TGA) analysis. The improvement in strength, deformation, and rheological properties, as well as the thermo-oxidative stability of the obtained nanocomposites, has been revealed, which is associated with the synergistic effect of the interaction of copper nanoparticles with maleic groups of MAPE. It has been shown that LDPE-based nanocomposites can be processed both by pressing and by injection molding and extrusion, which expands the scope of its application.