Maleic Anhydride-grafted Polyethylene Research Articles

Optimization of the performance of CsPbI2Br perovskite solar cells in air by adding polyethylene-graft-maleic anhydride and its mechanism

In this study, by adding Polyethylene-graft-maleic anhydride (PGMA) to the inorganic CsPbI2Br perovskite film, the coordination bonds and hydrogen bonds between PGMA and CsPbI2Br cooperate to passivate defects, regulate energy level and stabilize the perovskite structure and eventually improve the device performance. We systematically study the effects of PGMA addition on the morphology, structure, light absorption, defect concentration and carrier lifetime, hydrophobicity, and optical stability and room temperature black phase stability of CsPbI2Br films, and the photoelectric performance and air stability of PSCs, as well as their mechanism. The experimental results show that the addition of 3 wt% of PGMA greatly improves the photoelectric conversion efficiency (PCE) of CsPbI2Br PSCs by 40.19 % because of the synergistic passivation effects and energy level tuning. The hydrogen bonds between –CH2 in PGMA and I−/Br− in CsPbI2Br, along with the coordination of carbonyl groups with Cs+/Pb2+, improve carrier transport and collection by inactivating flaw and managing the level, reducing the non-radiative recombination losses. In addition, the PSCs with 3 wt% of PGMA maintain 80 % of their initial efficiency even after 600 h in high humidity air environment due to the synergistic effect of coordination bonds and hydrogen bonds. Our study provides valuable insights into the use of PGMA to improve the performance of all-inorganic CsPbI2Br PSCs and the practicality of perovskite solar cells.

Compatibilization of Polyamide 6/Cyclic Olefinic Copolymer Blends for the Development of Multifunctional Thermoplastic Composites with Self-Healing Capability.

This study investigated the self-healing properties of PA6/COC blends, in particular, the impact of three compatibilizers on the rheological, microstructural, and thermomechanical properties. Dynamic rheological analysis revealed that ethylene glycidyl methacrylate (E-GMA) played a crucial role in reducing interfacial tension and promoting PA6 chain entanglement with COC domains. Mechanical tests showed that poly(ethylene)-graft-maleic anhydride (PE-g-MAH) and polyolefin elastomer-graft-maleic anhydride (POE-g-MAH) compatibilizers enhanced elongation at break, while E-GMA had a milder effect. A thermal healing process at 140 °C for 1 h was carried out on specimens broken in fracture toughness tests, performed under quasi-static and impact conditions, and healing efficiency (HE) was evaluated as the ratio of critical stress intensity factors of healed and virgin samples. All the compatibilizers increased HE, especially E-GMA, achieving 28.5% and 68% in quasi-static and impact conditions, respectively. SEM images of specimens tested in quasi-static conditions showed that all the compatibilizers induced PA6 plasticization and crack corrugation, thus hindering COC flow in the crack zone. Conversely, under impact conditions, E-GMA led to the formation of brittle fractures with planar surfaces, promoting COC flow and thus higher HE values. This study demonstrated that compatibilizers, loading mode, and fracture surface morphologies strongly influenced self-healing performance.

Olive stone as a filler for recycled high-density polyethylene: A promising valorization of solid wastes from olive oil industry

The valorization of solid residues generated from olive oil production is a challenging issue for olive oil-producing countries such as Greece, Italy, Spain, etc. Olive stone waste is a type of lignocellulosic biomass with potential use as a natural additive in polymeric composites. In the present study, olive stone waste was compounded with recycled high-density polyethylene (rHDPE) via melt mixing in 5 %, 10 %, and 20 % wt. Additionally, the effect of Joncryl (JC) and polyethylene-grafted maleic anhydride (PE-g-MA) as compatibilizers on the properties of the green composites was also investigated. It is worth mentioning that JC was employed for the first time as a compatibilizer for polyolefin composites with olive stone. The materials underwent structural, thermal, and mechanical characterization using multiple complementary techniques. Scanning electron microscopy showed good dispersion of the filler for all composites, while in the compatibilized samples a markedly better adhesion was observed. Tensile tests revealed an increase in the elastic modulus for the composite with 10 % wt. olive stone. Furthermore, all materials demonstrated a strong antioxidant activity, rendering them interesting for active packaging applications. Overall, the solid residue from olive processing can enhance the properties of rHDPE, paving the way to promote circular economy.

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.

Green Bionanocomposites of Poly(Lactic Acid) (PLA) and Linear Low-Density Polyethylene (LLDPE): Fabrication and Properties

This study utilizes a polymer matrix made from a combination of Poly (Lactic Acid) (PLA) and Linear Low-Density Polyethylene (LLDPE). The polymer matrix is then improved by adding a compatibilizer, Polyethylene-graft-maleic anhydride (PE-g-MA), a filler, Recycled Tyre Waste (RTW), and a nano-scale filler, Graphene nanoplatelets (GNPs). Examining how PE-g-MA, RTW, and GNPs influence the binary blend's (PLA/RTW) chemical and thermo-mechanical characteristics is the focus of this study. A twin-screw extruder is used for the melting and intercalating processes. The binary mixture consists of 5% PE-g-MA, five percent RTW, and 3% GNPs. The samples are then pelletized after being cooled to room temperature. Analysis and characterization of the pelletized samples thermal and chemical characteristics follow. After including a compatibilizer, filler, and nanofiller into the bionanocomposite, improved qualities are anticipated.

Avocado Pruning Residues for the Formulation of Bio‐Based Polyethylene/Fiber‐Based Biocomposites for Sustainable Food Packaging

AbstractThe extensive use of non‐biodegradable bioplastics and fossil‐based plastics in food packaging presents a significant environmental challenge. Consequently, there has been a growing interest in exploring agricultural biomass as a potential source for formulating biocomposites for packaging due to the substantial amount of lignocellulosic residue generated. This study explores the utilization of avocado pruning residue (APR) for isolating lignocellulose fibers and their application as replacement and reinforcement material for bio‐based polyethylene (BioPE) composites. The results obtained reveal that a concentration of 9% (w/w) of maleic anhydride‐grafted‐polyethylene (MAPE) shows the most effective fiber–polymer interaction, resulting in a significant improvement of 25.47% in the mechanical properties. Biocomposites with varying fiber concentrations, ranging from 10% to 40% (w/w), are prepared and assessed for their macro‐ and micromechanical properties. The results demonstrate a substantial 49% increase in tensile strength and a remarkable 325% enhancement in Young's modulus for biocomposites containing 40% (w/w) fiber content. Furthermore, micromechanical analysis provides insights into the intrinsic strength and modulus of avocado fibers, with values of ≈437 MPa and 33 GPa, respectively. This research contributes to the development of sustainable and eco‐friendly alternatives for food packaging, reducing the reliance on fossil‐based plastics, and promoting the utilization of agricultural waste.

On the Mechanical, Thermal, and Rheological Properties of Polyethylene/Ultra-High Molecular Weight Polypropylene Blends.

The novel ultra-high molecular weight polypropylene (UHMWPP) as a dispersed component was melt blended with conventional high-density polyethylene (PE) and maleic anhydride grafted-polyethylene (mPE) in different proportions through a kneader. Ultra-high molecular weight polypropylene is a high-performance polymer material that has excellent mechanical properties and toughness compared to other polymers. Mechanical, thermal, and rheological properties were presented for various UHMWPP loadings, and correlations between mechanical and rheological properties were examined. Optimal comprehensive mechanical properties are achieved when the UHMWPP content reaches approximately 50 wt%, although the elongation properties do not match those of pure PE or mPE. However, it is worth noting that the elongation properties of these blends did not match those of PE or mPE. Particularly, for the PE/UHMWPP blends, a significant drop in tensile strength was observed as the UHMWPP content decreased (from 30.24 MPa for P50U50 to 13.12 MPa for P90U10). In contrast, the mPE/UHMWPP blends demonstrated only minimal changes in tensile strength (ranging from 29 MPa for mP50U50 to 24.64 MPa for mP90U10) as UHMWPP content varied. The storage modulus of the PE/UHMWPP blends increased drastically with the UHMWPP content due to the UHMWPP chain entanglements and rigidity. Additionally, we noted a substantial reduction in the melt index of the blend system when the UHMWPP content exceeded 10% by weight.

Effect of different modifiers on tobacco stalk fiber/high‐density polyethylene composites

AbstractAgricultural waste fiber has huge utilization potential due to its abundant sources, renewability, and low recycling costs. In this process, up to 30 wt% tobacco stalk fiber (TSF) was compounded with high‐density polyethylene (HDPE) and interfacial modifiers using a grinder, melting‐blending mixer, and injection molding machine to prepare environmentally friendly TSF/HDPE composites, which have excellent mechanical properties and good water resistance. On this basis, the interfacial compatibility between TSF and HDPE was enhanced by adding a silane coupling agent KH550, titanate coupling agent 201, and maleic anhydride grafted polyethylene (MA‐g‐PE), which led to the improvement of mechanical properties of composites. The mechanical properties of the composites with 2% MA‐g‐PE were the best, while the tensile strength and flexural strength increased by 72% and 38%, respectively, compared with the unmodified composites. Fourier transform infrared (FTIR) spectroscopy showed that TSF was modified by different coupling agents and new chemical bonds were formed. The scanning electron microscopy images showed that the interfacial compatibility between TSF and HDPE was improved by the interface modifiers. This work confirms that it is possible to use TSF to prepare composites and provides a new way for resource utilization of tobacco stalk fiber.Highlights TSF was incorporated into composites, boosting material sustainability. The interface compatibility between TSF and HDPE was greatly improved. Thermal and water absorption analysis can be used for composites design. Composites modified by 2 wt% MA‐g‐PE had optimal comprehensive properties.

Replacing Harmful Flame Retardants with Biodegradable Starch-Based Materials in Polyethylene Formulations.

The addition of toxic flame retardants to commercially available polymers is often required for safety reasons due to the high flammability of these materials. In this work, the preparation and incorporation of efficient biodegradable starch-based flame retardants into a low-density polyethylene (LDPE) matrix was investigated. Thermoplastic starch was first obtained by plasticizing starch with glycerol/water or glycerol/water/choline phytate to obtain TPS-G and TPS-G-CPA, respectively. Various LDPE/TPS blends were prepared by means of melt blending using polyethylene graft maleic anhydride as a compatibilizer and by varying the content of TPS and a halogenated commercial flame retardant. By replacing 38% and 76% of the harmful commercial flame retardant with safe TPS-G-CPA and TPS-G, respectively, blends with promising fire behavior were obtained, while the limiting oxygen index (LOI ≈ 28%) remained the same. The presence of choline phytate improved both the charring ability and fire retardancy of starch and resulted in a 43% reduction in fire growth index compared to the blend with commercial flame retardant only, as confirmed by means of cone calorimetry. Standard UL 94 vertical tests showed that blends containing TPS exhibited dripping behavior (rated V2), while those with commercial flame retardant were rated V0. Overall, this work demonstrates the potential of starch as a natural flame retardant that could reduce the cost and increase the safety of polymer-based materials.

Effect of Rice Husk and Wood Flour on the Structural, Mechanical, and Fire-Retardant Characteristics of Recycled High-Density Polyethylene.

Given the rising consumption of plastic products, it is becoming imperative to prioritize the recycling of plastic items as a solution to reducing plastic waste and environmental pollution. In this context, this research focuses on assessing the impact of incorporating rice husk and wood flour into recycled high-density polyethylene (rec-HDPE) to analyze its mechanical properties, flammability, and thermal stability. The combined rec-HDPE content of wood flour and rice husk varied between 0% and 20%. The rec-HDPE content of maleic anhydride grafted polyethylene (MAPE) was fixed at 3%. Mechanical characteristics such as flexural, tensile, and impact strengths were assessed. Cone calorimetry (CC) tests, limited oxygen index (LOI) tests, and horizontal and vertical burning tests were performed to determine the flammability or fire retardancy of these composites. On the other hand, to characterize the thermal characteristics of these composites, thermogravimetric analysis (TGA) was used. To further characterize the fluctuation in these characteristics, scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) studies were carried out. The mechanical characteristics were found to be increased in response to adding rice husk or wood flour. An 8% increase in tensile strength and a 20% increase in elastic modulus enhancement were recorded for a 20% rice husk-added composite. SEM revealed the reason for the variation in tensile properties, based on the extent of agglomeration and the extent of uniform distribution of fillers in rec-HDPE. Following these lines, the 20% rice husk-added composite also showed a maximum increase of around 6% in its flexural strength and a maximum increase of 50% in its flexural modulus. A decrease in impact strength was recorded for rice husk and wood flour-reinforced composites, compared with unreinforced rec-HDPE. Hybrid composites displayed a lack of mechanical strength due to changes in their nature. FTIR tests were performed for a much more elaborate analysis to confirm these results. Twenty percent of rice husk-added rec-HDPE displayed the best thermal properties that were tested, based on TGA and derivative thermogravimetric (DTG) analysis. This 20% composite also displayed the best fire-retardancy characteristics according to UL 94 tests, cone calorimetry tests, and limited oxygen index tests, due to the barrier created by the silica protective layer. These tests demonstrated that the incorporation of both fillers-rice husk and wood flour-effectively enhanced the thermal, mechanical, and fire-retardant attributes of recycled HDPE.

Dynamic Cross-Linked Polyethylene Networks with High Energy Storage and Electrical Damage Self-Healability.

Dielectric polymers that exhibit high energy density Ue, low dielectric loss, and thermal resistance are ideal materials for next-generation electrical equipment. The most widely utilized approach to improving Ue involves augmenting the polarization through increasing the dielectric constant εr or the breakdown strength Eb. However, as a conflicting parameter, the dielectric loss also increases inevitably at the same time. In addition, due to the long-term work under a strong electric field or high potential, dielectric materials often produce electrical damage (electrical tree), which is one of the main factors affecting the reliability and service life of electrical equipment. To address these problems, we herein develop dynamic cross-linked polyethylene materials (PE-MA-Epo) by polyethylene-graft-maleic anhydride (PE-MA) and polar epoxy monomers, which showed high εr (>7), low dielectric loss (<0.02), high Ue (5.16 J/cm3 at 425 MV/m), and outstanding discharge efficiency (97%). The performances of the materials are adequate to rival biaxially oriented polypropylene (BOPP) films. Moreover, the excellent self-healing capability of PE-MA-Epo enables the total recovery of εr and tan δ after electrical tree healing. After two cycles of electrical breakdown healing, Eb remained at 80%, which improves the durability and reliability of dielectric polymers. Therefore, PE-MA-Epo shows great potential for applications in advanced electronic power devices.

Optimization of the physical properties of recycled plastic hybrid composites reinforced with rubberwood flour and crab shell flour for underwater use

This research aimed to optimize the composition and physical properties of recycled high-density polyethylene (rHDPE) hybrid composites reinforced with rubberwood flour (RWF) and crab shell flour (CS) for application in water immersion. The effects of composition and deterioration in physical properties after immersion in different water conditions (distilled water and seawater) were investigated. D-optimal mixture experimental design and response surface methodology were applied. The findings showed that all the physical properties deteriorated with an increase in immersion times. The increasing addition of CS increased the density, water absorption, thickness swelling, and surface roughness of the samples before and after being immersed in distilled water and seawater. Further, the results revealed that the optimal composition for application in water immersion included 60.0 wt% rHDPE, 29.5 wt% RWF, 5.6 wt% CS, 3.5 wt% maleic anhydride-grafted polyethylene, 0.5 wt% ultraviolet stabilizers, and 1.0 wt% lubricant with a desirability score value of 95.80 %. The predicted response of density, color measurement, surface roughness, water absorption, and thickness swelling were 0.89 g/cm3, 10.11, 4.59 µm, 10.27 %, and 7.73 %, respectively. Based on the findings in this research, the effective application of naturally sourced additives in composite products, and using the optimized rHDPE, RWF, and CS contents would enable the development of alternative materials for applications in water immersion.

Enhancing interfacial adhesion through coupling agent incorporation in plywood/ plastic waste composite materials

The objective this study was to fabricate 5-ply boards using virgin and recycled high-density polyethylene (vHDPE and rHDPE) films as formaldehyde-free adhesives, respectively. To enhance the interfacial adhesion between the wood veneer and HDPE film, various loadings (0, 3, 6, 8, and 11 wt%) of polyethylene grafted maleic anhydride (PE-g-MA) were applied as a coupling agent. The physical and mechanical performance of the resulting plywood boards was evaluated using standard test methods, with a UF resin-bonded plywood used as a control for comparison. All materials used were for commercial-scale plywood production. Fourier transform infrared spectroscopy (FT-IR) results provided valuable information about chemical interactions that occurred during the coupling of poplar fibers with HDPE using PE-g-MA. The experimental results showed that the mechanical and physical properties of the plywood boards improved as the amount of coupling agent increased from 0 to 11 wt%. PE-g-MA played a crucial role in the properties of plywood boards made with rHDPE and vHDPE by enhancing the interfacial bonding ability between the HDPE and adjacent veneers, leading to good stress propagation and improved mechanical properties. The properties of samples bonded with vHDPE were significantly more improved than those made with rHDPE, likely due to the presence of color pigments, additives, fillers, and impurities in the rHDPE, which made the coupling agent less effective. In addition, the results demonstrated that the samples made with rHDPE and vHDPE were superior to the plywood bonded with UF resin (control), and the optimal content of the coupling agent was found to be 8 and 11 wt%. These findings suggest that incorporating recycled HDPE films and using coupling agents, such as PE-g-MA, can produce high-quality plywood composite materials with improved mechanical and physical properties, providing an eco-friendly alternative to traditional UF resin-bonded plywood.

Effect of Polyethylene-Grafted Maleic Anhydride on the Properties of Flue-Gas Desulfurized Gypsum/Epoxy Resin Composites

Waste resource utilization can save energy, reduce costs, and is one of the important means to protect the environment. Flue-gas desulphurized (FGD) gypsum is a common industrial by-product. These by-products are not only difficult to use, but also have serious impacts on the ecological environment. The conventional process of the industrial utilization of the calcium sulfate whisker pretreatment process leads to a low utilization rate of FGD gypsum, further increasing the consumption of resources and leading to secondary pollution. This study presents a method of preparing composites by adding FGD gypsum directly into epoxy resin with polyethylene-grafted maleic (PGM) anhydride as a compatibilizer of FGD gypsum/epoxy resin composites. Results showed weak tensile properties and impact properties of the composites when only FGD gypsum was added. When the amount of PGM added was 6 wt%, the tensile properties and impact properties of FGD gypsum/epoxy resin composites improved by 75% and 63%, and compared with the neat epoxy resin, the tensile properties and impact properties of FGD gypsum/epoxy resin composites, respectively, improved by 30% and 57%. Additionally, laser particle size analysis, X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), a thermogravimetric analyzer (TGA), and a Differential scanning calorimeter (DSC) were used to examine the effects of PGM on the mechanical properties of FGD gypsum/epoxy resin composites and its mechanism of action. The recycling of FGD gypsum in resin materials has been extended in this study.

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.

Evaluation of Eco-Friendly Hemp-Fiber-Reinforced Recycled HDPE Composites

The exploitation of natural fibers to reinforce polymers is a promising practice. Thus, biocomposites have gained increased attention in automotive, construction, and agricultural sectors, among others. The present work reports the reinforcement of recycled high-density polyethylene (r-HDPE) with hemp fibers to afford composite materials as sustainable analogues to conventional wood/plastic composite (WPC) products. HDPE bottles (postconsumer waste) were used as r-HDPE and further reinforced by the addition of hemp fibers. For the synthetic part, thirteen composite materials with different filler concentrations (10–75% wt. in hemp fibers) using either Joncryl or polyethylene-grafted maleic anhydride (PE-g-MA) as compatibilizers were prepared via melt mixing. Materials with good integrity were obtained with a fiber load as high as 75% wt. The structural, thermal, mechanical, and antioxidant properties of the r-HDPE/hemp composites were evaluated using multiple complementary characterization techniques. Stereoscopic microscope images demonstrated the satisfactory dispersion of the hemp fibers into the polymeric matrix, while scanning electron microscopy microphotographs revealed an improved adhesion between the filler and the polymeric matrix in the presence of compatibilizers. The incorporation of hemp fibers contributed to the improvement of the elastic modulus of the composites (almost up to threefold increase). The results showed that as the hemp fiber content increased, the antioxidant properties as well as the degradability of the composites increased. It is noteworthy that composites containing 75% wt. hemp fibers neutralized 80% of 2,2-diphenyil-1-picrylhydrazyl radicals within 45 min (DPPH assay). In conclusion, the present research work demonstrates that thermally recycled HDPE reinforced with biomass fibers received from agricultural waste is a valid alternative for the preparation of commodity products with an eco-friendly character compared to conventional wood/plastic composites.

Interfacial rheology for probing the in-situ chemical reaction at interfaces of molten polymer systems

The design of new functional materials from immiscible polymers or multi-layered structures using reactive compatibilisation is an efficient approach that has been extensively employed in a wide range of applications. The adhesion/interfacial properties in these multiphase polymeric systems depend on the extent of reaction occurring at the interface. However, probing in-situ interfacial reactions in the molten state has proved challenging. In this study, interfacial shear rheology is used for the first time to directly probe the reaction at the interface between maleic anhydride-grafted polyethylene (PEgMA) and aminopropyl-terminated polydimethylsiloxane (PDMS-(PropNH2)2) used as model reactive polymer systems. Then the reaction at the interface was investigated using interfacial shear rheology based on a newly homemade, lightweight biconical setup. Thereafter, the time evolution of the interfacial tension with the progress of interfacial reaction was assessed using the pendant drop method. First, the extent of reaction was checked using differential scanning calorimetry (DSC) and dynamic rheology coupled with fast-scan FTIR spectroscopy. It has been demonstrated that the molecular weight of the aminated PDMS and the temperature of the medium markedly affect the rate of melt reaction at the interface and related interfacial rheological properties. Interestingly, the ability to assess the reactions at the interface in PEgMA/PDMS-(PropNH2)2 systems, even with low concentrations of reactive functionalities, demonstrates that interfacial rheology is a suitable, sensitive probe that could be applied to other reactive polymer systems, allowing better control of the resulting physical properties.

Development of Cork Biocomposites Enriched with Chitosan Targeting Antibacterial and Antifouling Properties.

The demand for bio-based and safer composite materials is increasing due to the growth of the industry, human population, and environmental concerns. In this framework, sustainable and safer cork-polymer composites (CPC), based on green low-density polyethylene (LDPE) were developed using melt-based technologies. Chitosan and polyethylene-graft-maleic anhydride (PE-g-MA) were employed to enhance the CPC's properties. The morphology, wettability, mechanical, thermal, and antibacterial properties of the CPC against Pseudomonas putida (P. putida) and Staphylococcus aureus (S. aureus) were examined. The CPC showed improved stiffness when compared with that of the LDPE matrix, preferably when combined with chitosan and PE-g-MA (5 wt. %), reinforcing the stiffness (58.8%) and the strength (66.7%). Chitosan also increased the composite stiffness and strength, as well as reduced the surface hydrophilicity. The CPCs' antibacterial activity revealed that cork significantly reduces the biofilm on the polymer matrix. The highest biofilm reduction was found with CPC containing cork and 5 wt. % chitosan for both P. putida (54% reduction) and S. aureus (36% reduction), confirming their potential to extend the lifespan of products for packaging and healthcare, among other applications. This work leads to the understanding of the factors that influence biofilm formation in cork composites and provides a strategy to reinforce their behavior using chitosan.

Blending of Low-Density Polyethylene and Poly(Butylene Succinate) (LDPE/PBS) with Polyethylene-Graft-Maleic Anhydride (PE-g-MA) as a Compatibilizer on the Phase Morphology, Mechanical and Thermal Properties.

It is of significant concern that the buildup of non-biodegradable plastic waste in the environment may result in long-term issues with the environment, the economy and waste management. In this study, low-density polyethylene (LDPE) was compounded with different contents of poly(butylene succinate) (PBS) at 10-50 wt.%, to evaluate the potential of replacing commercial plastics with a biodegradable renewable polymer, PBS for packaging applications. The morphological, mechanical and thermal properties of the LDPE/PBS blends were examined in relation to the effect of polyethylene-graft-maleic anhydride (PE-g-MA) as a compatibilizer. LDPE/PBS/PE-g-MA blends were fabricated via the melt blending method using an internal mixer and then were compression molded into test samples. The presence of LDPE, PBS and PE-g-MA individually in the matrix for each blend presented physical interaction between the constituents, as shown by Fourier-transform infrared spectroscopy (FTIR). The morphology of LDPE/PBS/PE-g-MA blends showed improved compatibility and homogeneity between the LDPE matrix and PBS phase. Compatibilized LDPE/PBS blends showed an improvement in the tensile strength, with 5 phr of compatibilizer providing the optimal content. The thermal stability of LDPE/PBS blends decreased with higher PBS content and the thermal stability of compatibilized blends was higher in contrast to the uncompatibilized blends. Therefore, our research demonstrated that the partial substitution of LDPE with a biodegradable PBS and the incorporation of the PE-g-MA compatibilizer could develop an innovative blend with improved structural, mechanical and thermal properties.

Effect of moisture absorption-desorption cycles, UV irradiation and coupling agent on the mechanical performance of pinewood waste/polyethylene composites

&lt;abstract&gt; &lt;p&gt;The effects of UV radiation, a maleic anhydride grafted polyethylene (MAPE) coupling agent and moisture cycling exposure on wood plastic composites (WPC) made from pinewood waste (PW) and high-density polyethylene (HDPE) on their tensile and flex properties, were studied. First, the effect of UV radiation and the presence of anhydride grafted polyethylene on the absorption-desorption behavior of the compounds was evaluated and then its effect on the mechanical properties. Scanning electron microscopy (SEM) was used to analyze the surfaces of the samples subjected to these factors and their subsequent damage in fracture zones of the samples. The moisture absorption-desorption process exhibited a two-stage mechanism: the first is significant increases in the absorption values in the first five cycles, and a second stabilization stage that occurs from the sixth cycle onwards. The first stage includes several steps: initial absorption and delamination; capillary action and polymer-wood interaction; and swelling, fiber-matrix interaction and mechanical damage. The second stage involves the balance and stabilization step. Statistically, it was found that the changes in the humidity values in the absorption and desorption cycles show that UV radiation has a significant contribution with the effect of increasing the absorption and desorption values, while the presence of anhydride grafted polyethylene as a lesser effect with an effect of decreasing those values. The tensile and flexural properties of the compounds were significantly affected by UV radiation and moisture cycling. Taking the sample without anhydride grafted polyethylene and without treatments as a reference, only a slight increase of 5–12% in its tensile and flexural properties was observed, while treatments with UV radiation and absorption-desorption cycles reduced them by up to 45%. The SEM analysis confirmed the deterioration of the composites in the form of microcracks, delamination, interfacial voids and mechanical failures in both the wood filler and the polyethylene matrix, especially in the samples exposed to ultraviolet radiation, where this deterioration was lower in the samples containing anhydride grafted polyethylene.&lt;/p&gt; &lt;/abstract&gt;