Maleic Anhydride-grafted Polypropylene Research Articles

Enhanced Energy Storage Properties of PP/PA11 Dielectric Composite Films With PP‐g‐MAH as Compatibilizer

ABSTRACTAs an energy storage capacitor film material, polypropylene (PP) suffers from its low dielectric constant and limited energy density. To overcome the defects of pure PP, the PP‐based all‐organic composite films with multiple interfaces have been constructed to enhance the dielectric and energy storage properties. In this research, PA11 was used to blend with PP with polypropylene grafted maleic anhydride (PP‐g‐MAH) as compatibilizer. The prepared PP/PP‐g‐MAH/PA11 composites formed the typical “sea‐island” structure and double interfaces between PP/PP‐g‐MAH and PP‐g‐MAH/PA11. The higher molecular polarity of PP‐g‐MAH, PA11, and interfacial polarization significantly increases the dielectric constant of the composite films. Furthermore, the formation of interface traps suppressed the migration of charge carriers, resulting in lower leakage current and higher breakdown strength of the PP/PP‐g‐MAH/PA11 composite films. Density functional theory (DFT) simulation further proved the confinement of space charges. Energy storage results showed the optimal PP/PP‐g‐MAH/PA11‐2 film achieved high energy density (4.49 J/cm3) and excellent charge/discharge efficiency (97.4%), which behaved good application prospect in the field of thin film capacitors.

Wood Polymer Composites Based on the Recycled Polyethylene Blends from Municipal Waste and Ethiopian Indigenous Bamboo (Oxytenanthera abyssinica) Fibrous Particles Through Chemical Coupling Crosslinking.

Valorization of potential thermoplastic waste is an effective strategy to address resource scarcity and reduce valuable thermoplastic waste. In this study, new ecofriendly biomass-derived wood polymer composites (WPCs) were produced from three different types of recycled polyethylene (PE) municipal waste, namely linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), or high-density polyethylene (HDPE), and their blend with equal composition (33/33/33 by wt.%). Bamboo particle reinforcement derived from indigenous Ethiopian lowland bamboo (LLB), which had never been utilized before in a WPC formulation, was used as the dispersed phase. Before utilization, recycled LLDPE, MDPE, and HDPE were carefully characterized to determine their chemical compositions, residual metals, polycyclic aromatic hydrocarbons, and thermal properties. Similarly, the fundamental mechanical properties of the WPCs, such as tensile strength, modulus of elasticity, flexural strength, modulus of rupture, and unnotched impact strength, were evaluated. Finally, the thermal stability and interphase coupling efficiency of maleic-anhydride-grafted polypropylene (MAPP) were carefully investigated. WPCs formulated by melt-blending either of the recycled PEs or the blend of recycled PE with bamboo particles showed significant improvement due to MAPP enhancing interfacial adhesion and thermally induced crosslinking, despite inherent immiscibility. These results were confirmed using Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The formulated WPCs may promote PE waste cascading valorization, offering sustainable alternatives and maximizing LLB utilization. Furthermore, comparison with well-known standards for polyolefin-based WPCs indicated that the prepared WPCs can be used as alternative sustainable building materials and related applications.

Bioinspired surface modification of mussel shells and their application as a biogenic filler in polypropylene composites

This study explores the potential of mussel shells (MS) as biogenic fillers in polymer composites. The chemical composition and crystal structures of MS were characterised. To improve MS filler dispersion and adhesion within a polypropylene (PP) matrix, three surface modification methods were evaluated: polydopamine (PDA) coating, maleic anhydride-grafted polypropylene (MAPP) modification, and PDA/MAPP co-modification. The PDA coating, inspired by the adhesive properties of mussel foot proteins, successfully functionalized the MS surface, as confirmed by X-ray photoelectron spectroscopy (XPS). Thermodynamic analysis, based on contact angle measurements, revealed that MAPP and PDA/MAPP modifications reduced surface energies and potential energy differences. These changes enhanced filler dispersion and interfacial bonding by increasing hydrophobicity and reducing agglomeration in the PP matrix. Consequently, PP composites with 20% PDA/MAPP-modified MS fillers exhibited a 2.9% increase in tensile strength and a 7.5% increase in flexural strength compared to neat PP. Scanning electron microscopy (SEM) also showed reduced filler-matrix debonding and fewer voids. The proposed mechanism attributes these macroscopic property enhancements to the ability of the PDA coating to facilitate chemical and hydrogen bonding between MS fillers and MAPP.

Biodegradation Behaviour of the Composite Consisting of Polypropylene and Bauhinia Vahlii Fiber

AbstractThe current study focuses on the degradation rate of polypropylene (PP) and Bauhinia Vahlii (BV) fibers under soil burial and natural weathering conditions for 360 days. The BV‐PP composite was produced with varying BV fiber compositions (0, 10, 20, and 30 wt.%) and 3 % MAPP (Maleic Anhydride Grafted Polypropylene). In addition, MAPP is employed as a coupling agent to improve fiber‐matrix compatibility and promote degradation. The XRD examination shows that a 10 % BV‐PP composite has a crystallinity index of 52.05 %, which is higher than that of neat PP. The rate of biodegradability was investigated using weight loss and tensile properties. The largest degradation was seen in natural weathering conditions with 30 % composite showing the maximum weight loss of 3.8 % and loss in tensile strength and modulus of 16.76 % and 5.11 %, respectively. Simultaneously, no weight loss or drop in tensile characteristics was found in the case of neat PP over 360 days. The SEM images of soil burial show material deterioration, which may be aided by bacterial and fungal activity, whereas natural weathering conditions show a large crack, rougher fracture surface, and cavities, which are attributed to thermal stresses, changes in moisture content, and ultraviolet radiation, thereby promoting the degradation process.

Melt compounding of spray-dried cellulose nanofibrils/polypropylene and their application in 3D printing

Micro- and nano-scale cellulosic fillers exhibit excellent dispersion and distribution within a thermoplastic matrix during the process of melt compounding or injection molding. In this study, spray-dried cellulose nanofiber (SDCNF) powders were manufactured using a pilot-scale rotating disk atomizer spray dryer. Bleached Kraft pulp (BKP), unbleached Kraft pulp (UKP), and old corrugated cardboard pulp (OCC) fibrillated at a fines level of 90% were used as feedstock materials for spray-drying. BKP-, UKP-, and OCC- SDCNFs were compounded with polypropylene using a twin screw co-rotating extruder. Maleic anhydride grafted polypropylene (MAPP) was used as a coupling agent in the composite formulations. The tensile, flexural, and impact properties of SDCNF-filled PP composites increased at 10 wt% SDCNF loading. The presence of SDCNFs in the PP matrix resulted in faster crystallization and a 12% reduction in the degree of crystallinity of the neat PP. The coefficient of thermal expansion (CTE) of neat PP was reduced by up to 31% attributable to the presence of the SDCNFs. Application of the SDCNF-reinforced PP composites in 3D printing reduced the shrinkage rate of the printed neat PP by 39%, and the printability of the PP was significantly improved with the addition of the SDCNFs.

Optimization of malic anhydrate concentration in manufacturing PP-g-MA compatibilizer on test percent of grafting degree

The difference in polarity means that two or more materials cannot react, a connecting material such as a compatibilizer is needed to react between polar and non-polar materials. This research aims to determine the effect of maleic anhydride (MA) concentration on the process of grafting MA onto polypropylene (PP) chains with the help of benzoyl peroxide (BPO) as an initiator. The method used to mix these two materials uses the blending method using an internal mixer instrument and testing the percent degree of grafting using the titration method with three repetitions of the test.The research results showed that the highest percent grafting degree occurred at a concentration of 86% PP, 11% MA, and 3% BPO, with a value of 10.28%. The Spectroscopy Fourier Transform Infrared (FTIR) analysis of Polypropylene grafted maleic anhydride (PP-g-MA) showed the presence of new peaks at wavenumbers 1707cm-1 and 1162 cm-1.Increasing the concentration of maleic anhydride had no effect on increasing the percent degree of grafting.

Enhanced High-Performance iPP/TPU/MWCNT Nanocomposite for Electromagnetic Interference Shielding.

The rapid development of electronic communication technology has led to an undeniable issue of electromagnetic pollution, prompting widespread attention from researchers to the study of electromagnetic shielding materials. Herein, a simple and feasible method of melt blending was applied to prepare iPP/TPU/MWCNT nanocomposites with excellent electromagnetic shielding performance. The addition of maleic anhydride-grafted polypropylene (PP-g-MAH) effectively improved the interface compatibility of iPP and TPU. A double continuous structure within the matrix was achieved by controlling the iPP/TPU ratio at 4:6, while the incorporation of multi-walled carbon nanotubes endowed the composites with improved electromagnetic shielding properties. Furthermore, by regulating the addition sequence of raw materials during the melt-blending process, a selective distribution of carbon nanotubes in the TPU matrix was achieved, thereby constructing interconnected conductive networks within the composites, significantly enhancing the electromagnetic shielding performance of iPP/TPU/MWCNTs, which achieved a maximum EMI shielding efficiency of 37.8 dB at an iPP/TPU ratio of 4:6 and an MWCNT concentration of 10 wt.%.

Development of microstructure-rheological and electrical properties relationship in PS/POE/HNTs blend nanocomposites using machine learning

Halloysite nanotubes (HNTs) and polypropylene-grafted maleic anhydride (PP-g-MA) were studied for their effects in blends of polystyrene (PS) and polyolefin elastomer (POE). The method used to prepare PS/POE blends (90/10 and 80/20 wt/wt) containing 1, 3, and 5 phr HNTs with or without PP-g-MA (a compatibilizer) was melt blending. Structural and morphological studies using X-ray diffraction analysis (XRD), scanning electron microscopy assisted energy dispersive X-ray spectroscopy (SEM-EDS), and transmission electron microscopy (TEM) confirmed a matrix-droplet morphology and the sample containing compatibilizer has better microstructure than the other formulations. The presence of both PP-g-MA and HNTs together has been discovered to improve the viscoelastic properties of the solid, as evidenced by increased storage modulus and complex viscosity. A notable change occurred in the rheological behavior of the PS/POE blends containing 5 phr of PP-g-MA and HNTs. The dependence of zero-shear viscosity on HNTs loading (0–5 phr) was approximated as a polynomial curve by fitting the experimental data with the Carreau-Yasuda model. Computational fluid dynamics (CFD) simulations were also used to study the effects of HNTs loading on changes in fluid flow patterns and shear rates. The calculated effective viscosities at a given shear rate (0.05 1/s) were in qualitative agreement with the experimental results. Moreover, we utilized various machine-learning techniques to predict the complex viscosity of PS/POE blends and their nanocomposites. The results showed that Extreme Gradient Boosting (XGBoost) outperformed other predictive models based on evaluation metrics. Four-point probe measurements found that the samples containing 5 phr HNT had the lowest conductivities due to the presence of aggregated structures. However, the homogeneous distribution of HNT led to a sudden rise in conductivity in the samples containing 5 phr of PP-g-MA. Computer modeling results of samples with uniform and non-uniform HNT distributions showed that the conductivity decreased with HNT loading and decreased considerably compared to the uniform distribution.

Functionalized boron nitride nanosheets and their polypropylene nanocomposites: influence on thermal, mechanical, rheological and wear behaviour

ABSTRACT The few-layer hexagonal boron nitride (hBN) nanosheets with hydroxyl (−OH) functional group at edges are synthesized using heat treatment of micron size hBN powder followed by sonication. These nanosheets are modified with a silane coupling agent, 3-Aminopropyl,triethoxysilane (APTES). The synthesized hBN nanosheets are mixed with the PP matrix using twin-screw extrusion followed by injection moulding. In case of APTES-modified hBN nanosheets incorporation in the PP matrix with PP-grafted maleic anhydride (PP-g-MA) shows the formation of an imide bond between the MA functional group of PP-g-MA and the amine group of APTES modified hBN nanosheets revealing compatibilization. The flow behaviour index values are lower for hBN nanosheets filled PP nanocomposites showing the improved processability from Rheological characterization. The few-layered – OH and APTES modified hBN nanosheet incorporation in the PP matrix improves the tensile and thermal properties. The incorporation of APTES modified hBN nanosheet in the PP matrix shows an increase in tensile modulus (18.1%) and tensile strength (8.1%) respectively. Wear studies show the incorporation of – OH and APTES modified hBN nanosheets in the PP matrix decreases the coefficient of friction and wear rate significantly. The wear rate at 4 min of wear testing for modified hBN nanosheet in the PP nanocomposites is ~ 96% less in comparison with neat PP. The wear mechanism is established from wear measurements and scanning electron microscopy (SEM) of worn-out wear surfaces of PP nanocomposites.

Electrical properties of MAH-g-PP modified PP/SEBS matrix semi-conductive composite materials

Polypropylene (PP) becomes a superior candidate material for new environmental-friendly cable insulation layer with its excellent heat resistance, electrical properties and degradability. At present, most of studies focus on the insulation layer of PP cable. However, there are few studies on semi-conductive shielding layer of PP cable which match its insulation layer. In this paper, polypropylene (PP)/styrene ethylene butylene styrene (SEBS) is adopted as matrix of PP cable semi-conductive layer to matching its insulation layer. Meanwhile, Maleic anhydride grafted polypropylene (MAH-g-PP) is used to cooperatively improve the compatibility between PP and SEBS. The physicochemical properties, space charge injection properties and compatibility of semi-conductive composites with different CB and MAH-g-PP contents is studied by combining experiment and simulation methods. The experimental results show that the surface roughness of the semi-conductive layer and the space charge inside the insulation layer decrease first and then increase with the increase of CB addition. Among them, the two parameters of 25 phr CB semi-conductive layer is the lowest, respectively 13.98 nm and 2.25 × 10−8C. These two parameters are significantly reduced after the addition of compatibilizer MAH-g-PP, which decreased by 29.47 % and 62.22 %, respectively. The simulation results show that the Flory-Huggins interaction parameters (χ) of MAH-g-PP with PP and SEBS are −73.3 and −45.2, respectively, which are 236.24 % and 107.34 % lower than those of PP/SEBS. The χ value of MAH-g-PP/CB is 8.20, which is 33.27 % and 9.59 % lower than CB/PP and CB/SEBS, respectively. It shows that MAH-g-PP can effectively improve the compatibility of matrix and filler. This work has important guiding significance for the research of semi-conductive layer formulation of PP cable.

Effect of wood flour and compatibilizer content on the properties of wood-plastic composites

Wood-plastic composites (WPC) with are prepared by melting and mixing wood flour (WF) and thermoplastics which has green and biodegradable advantages and is of great significance in the development of the era of global resource scarcity. In this work, recycled polypropylene and WF were used as raw materials and commercially available maleic anhydride grafted polypropylene (MAH-g-PP) was used as a compatibilizer. The extrusion injection molding method was used and investigated by varying the amount of WF and compatibilizer added. The composites were analyzed for micro-morphology, melt mass flow rate, mechanical properties, and thermal stability by scanning electron microscopy (SEM), melt flow rate tester (MFR), electronic universal testing machine, and thermogravimetric analysis (TGA). According to the results, WF shows a positive effect in terms of storage and loss modulus of the composites, but it shows a negative effect in terms of thermal stability and mechanical properties. As an effective compatibilizer, MAH-g-PP plays an important role in improving the mechanical properties of the composites, especially at an additional level of 4 wt%, which maximized the overall performance of the composites.

Preparation and characterization of hybrid PLA biocomposites reinforced by wood and silane treated basalt fibers or compatibilized by maleic anhydride‐grafted polypropylene (MAPP)

AbstractIn this study, basalt and/or beech wood fibers were treated with vinyltrimethoxysilane or compatibilized by maleic anhydride‐ grafted polypropylene (MAPP) to produce hybrid polylactic acid (PLA) biocomposites. Twin‐screw extruder was used to produce biocomposites, following by a hot press to form samples. Physical and mechanical properties of composites that were produced from both treated and untreated fibers were compared. Chemical, morphological, and thermal analysis of biocomposites were analyzed with TGA, FTIR and SEM, respectively. The results showed that silane treated basalt/wood fiber reinforced PLA (PBWS) and silane treated basalt reinforced PLA (PBS) have significantly better flexural strength than neat PLA. Besides, basalt reinforced bio‐composites except PBW3 and PBWM variations have significantly superior impact strength than neat PLA. Utilization of compatibilizers also reduced thickness swelling and water uptake features of biocomposites. All the above experimental data showed that the utilization of silane compatibilizer has better impact on properties than MAPP for such wood/basalt hybrid composite.Highlights Hybrid biocomposites with wood and basalt fibers by using coupling agents were prepared for the first time. Hybridization of organic and inorganic fibers gave promising results. Silane and maleic anhydride compatibilization improves physical properties. Vinyltrimethoxy silane grafted basalt fiber improves flexural strength significantly. Silanization of wood or basalt fibers enhances significantly the impact strength.

Carbon Fiber Reinforced Recycled Polypropylene/Polyolefin Elastomer Composites with High Mechanical Properties.

The treatment of waste plastics has gradually become a hot topic in the current scientific community. In response to the needs for high-impact performance R-PP-based composites, carbon fiber (CF)-reinforced polyolefin elastomer (POE)/recycled polypropylene (R-PP) composite (CF/POE/R-PP) was prepared by the mechanical blending method, and its mechanical and thermal properties were systematically studied. It was found that the CF could effectively improve the bending and notch impact strength as well as enhance the thermal stability of POE/R-PP. Furthermore, a stable and dispersed composite interface formed by the combination of maleic anhydride-grafted polypropylene (PP-g-MAH) with the surface of CF and the fusion alkyl chains in R-PP and POE further enhanced the CF's reinforcing effect. As a result, the addition of 9 wt.% CF successfully improved the heat resistance of the composite material, and the residual carbon content increased by 97.84% after sintering. The composite toughening of POE and CF effectively improved the impact strength of the composite material, with a maximum increase of over 1000%. This study ultimately resulted in a high-impact-resistant composite material.

Lionomers versus Zn-Ionomer: A new route for the preparation of microcellular foams

In this work, LIonomers based on maleic anhydride-grafted polypropylene (PPgMA) are successfully designed. These LIonomers are developed from the addition of two imidazolium-based ionic liquids (ImILs) to PPgMA: one unreactive ImIL, i.e. 1-ethyl-3-methylimidazolium diethyl phosphate (E+DEP), and one reactive ImIL, i.e. 1-aminoethyl-3-methylimidazolium bromide (AE+Br). Thus, the effect of the ImIL nature on LIonomers properties was highlighted and those ones compared to conventional Zn-Ionomer. Firstly, NMR and FTIR spectroscopies have revealed the existence of ionic-polar/ionic interactions and/or the creation of chemical bonds depending on the chemical nature of ImILs. These various interactions in polymer blends lead to the different multiscale structurations, i.e. a dual assembling of ionic species (including multiplets and large clusters) and homogeneous morphologies on the blends with E+DEP and AE+Br compared to the phase separation of ions occurring for conventional Zn-Ionomer. The rheological properties have highlighted the presence of such interactions between maleic anhydride groups and cations or anions for the imidazolium IL-based LIonomers, similar to the interactions of Zn2+ with anions pairs within Zn-Ionomers. Thanks to the existence of maleic anhydride/ImIL interactions and the generation of β-crystalline form as well as the various ionic-rich phases, an outstanding compromise between stiffness and stretchability was achieved from LIonomers. In addition, considering supercritical carbon dioxide (scCO2) as physical foaming agent, the foamability of PPgMA has been considerably improved thanks to the ionic networks formed by ionic liquids compared to Zn2+ acetate addition. Finally, the foam morphology and the compressive behavior were investigated as a function of the cation/anion combination of ILs or Zn2+Ac addition.

Effect of Coupling Agent on the Properties of Pineapple Leaf Fiber/ Polypropylene Composite

Natural fibre matrix composites have been utilized in numerous industries, including the automotive, construction, and aerospace sectors. Maleic anhydride grafted polypropylene (MAPP) was used in this study to examine the effect of the coupling agent on the properties of a composite-produced using pineapple leaf fibre. The weight ratios of pineapple leaf fibre, polypropylene, and MAPP were 20g:180g, 15g:180g:5g, and 10g:180g:10g, respectively. The materials were mixed using a co-rotating twin-screw extruder machine at 170 °C and 50 rpm. The composite was then manufactured by injection molding at 185 °C. The mechanical and physical properties of PALF composite were examined by using a tensile test, impact test, and water absorption test. Thermal Gravimetric Analysis (TGA) was used to characterize the thermal properties of PALF/PP, and PALF/PP/MAPP composite. The surface morphology and fracture surface of the composite was characterized by using Scanning Electron Microscopy (SEM). Compared to the composite containing 5 g of MAPP, the tensile strength composite containing 10 g of MAPP produced a stronger interfacial bond. According to the impact test, adding more MAPP increases the material's strength and stress transmission. The average percentage of water absorption indicates low water absorption after the addition of the coupling agent. It can be concluded that the addition of a coupling agent improved the composite's properties.

Enhancing Mechanical Performance of High-Lignin-Filled Polypropylene via Reactive Extrusion.

Polypropylene (PP) is one of the most extensively used commodity plastics. In terms of eco-friendliness, it is worth considering preparing high-lignin-filled PP. This study explores the incorporation of high lignin content, derived from acetic acid lignin (AAL) and Kraft lignin (KL), into PP through twin-screw extrusion and injection molding. The challenge lies in maintaining mechanical performance. A compatibilizer-specifically, maleic anhydride-grafted polypropylene (MAPP)-is employed to enhance lignin-PP compatibility by chemically bonding with lignin and physically associating with the PP phase. Results indicate that KL maintains better dispersity than AAL. Compatibilizers with a high maleic anhydride (MA) level (≥0.8 wt.%) and moderate melt flow index (MFI) in the range of 60-100 g 10 min⁻¹ prove favorable in constructing a reinforced PP/KL network. Optimizing with 40 wt.% lignin content and 10 parts per hundred (pph) of compatibilizer yields blends with mechanical performance comparable to neat PP, exhibiting a notable increase in modulus and heat deflection temperature (HDT). Furthermore, utilizing PP/lignin blends can lead to a 20% reduction in expenses and approximately 40% reduction in PP-induced greenhouse gas (GHG) emissions. This approach not only reduces PP costs but also adds value to lignin utilization in a sustainable and cost-effective manner.

Surface modification of zinc oxide and its application in polypropylene with excellent fire performance and ultra-violet resistance

Despite the advantages of easy moulding and excellent mechanical properties, there are still some shortcomings with polypropylene (PP) such as high flammability and poor ultra-violet (UV) resistance. In this work, modified zinc oxide (mZnO) was prepared by reacting zinc oxide nanoparticles (ZnO) with polysiloxanes, and the effect of mZnO on the effectiveness of intumescent flame-retardant and on the UV aging resistance of polypropylene were investigated. By introducing 16 wt% (intumescent flame-retardant /mZnO) and 0.3 wt% maleic anhydride-grafted PP (MAH-g-PP), the limiting oxygen index increased to 32.7 %, and passed UL-94V-0 rating. In comparison to the controls, the peak heat release rate and the peak smoke release rate were 88.5 % and 80 % lower, respectively. In addition, PP samples showed improved mechanical properties, with a 5 % increase in tensile properties compared to the pure PP sample. After 100 h of UV irradiation, the surface of the samples was relatively flat and smooth, and the carbonyl index decreased from 81.1 of neat PP to 26.7. PP composites with 100 h aging treatment still had excellent flame retardancy and mechanical properties. The results showed that mZnO was effective in improving the flame retardancy, mechanical properties and light aging tolerance of PP. This study provides a novel approach to fabricate long-life flame-retardant PP composites with low additive content.

Utilization of flours from hemp stalks as reinforcement in polypropylene matrix

Utilization of hemp stalks (HS) was investigated as filler and maleic anhydride-grafted polypropylene (MAPP) as a coupling agent relative to some mechanical, physical, morphological, and thermal properties of polypropylene (PP) composites. The test sample manufacturing used 10, 15, 20, 25, 30, and 35 wt% of HS and 0 wt% or 3 wt% of MAPP. Test specimens were manufactured by combining extrusion and injection molding processes. Results showed that incorporating filler and MAPP increased the mechanical properties significantly. The utilization of HS filler or MAPP provided an improvement of 11.7% (samples containing 35 wt% HS and 3 wt% MAPP) improvement in tensile strength, 44.2% (samples containing 35 wt% HS and 3 wt% MAPP) in flexural strength, and 60.2% (samples containing 30 wt% HS and 0 wt% MAPP) in impact strength compared to neat PP. The scanning electron microscopy analysis provided visual evidence that MAPP improved adhesion between the filler and the polymer matrix. This study showed that using hemp stalks in composite manufacturing provided good overall properties.

Influence of graphene nanoplatelets (GNPs) and aluminum-carbon layered double hydroxides (Al-C LDH) in polypropylene matrix of hybrid composite structures on the microstructure and mechanical performances

<p>In this study, a polypropylene (PP) matrix was reinforced with ultra-fine graphene nanoplatelets (GNPs), aluminum-carbon layered double hydroxides (Al-C LDHs), and calcium carbonate (CaCO<sub>3</sub>) as hybrid reinforcements, along with polypropylene grafted maleic anhydride (PP-g-MA) compatibilizers to create a novel thermoplastic-based hybrid composite polymer. The hybrid composite consisted of varying weight percentages of GNPs (ranging from 0.5 to 2.0 wt% in increments of 0.5), 2wt% Al-C LDH, 2wt % CaCO<sub>3</sub>, and 5wt % PP-g-MA. The bulk samples were manufactured using twin-screw extrusion followed by vertical injection molding. The developed hybrid composites were characterized using high-resolution scanning electron microscopy (HRSEM) for microstructural analysis, X-ray diffraction (XRD) for phase identification, X-ray photoelectron spectroscopy (XPS) for compositional analysis, and Fourier-transform infrared spectroscopy (FTIR) for functional group identification. Thermogravimetric analysis (TGA) was performed to assess thermal stability, crystallization, and melting behavior. Mechanical tests, including tensile, compressive, and three-point bending, were conducted to evaluate mechanical properties, while a low-velocity impact test assessed impact resistance. The results showed that the hybrid composite with a PP matrix embedded with 1.5 wt% GNPs, 2 wt% Al-C LDH, and 2 wt% CaCO<sub>3</sub> exhibited improved mechanical properties, achieving an ultimate tensile strength of approximately 45 MPa. This enhancement is attributed to the effective interconnection, bonding, and cross-linking of the reinforcements with the PP matrix, facilitating efficient load transfer, which makes it suitable for structural applications.</p>

Synthesis, characterization, thermal and mechanical behavior of polypropylene hybrid composites embedded with CaCO<sub>3</sub> and graphene nano-platelets (GNPs) for structural applications

<abstract> <p>In this study, ultra-fine graphene nanoplatelets (GNPs) were employed as nanofillers to reinforce a polypropylene (PP) matrix. This was done in conjunction with a polypropylene grafted maleic anhydride (PP-MAH) compatibilizer and calcium carbonate (CaCO<sub>3</sub>), with the aim of improving the mechanical and thermal properties of the resulting hybrid composites. Formulations for the hybrid composites were fabricated by compounding the PP matrix with varying weight percentages of GNPs (x = 0.5, 1.0, 1.5, 2.0), 2 wt.% CaCO<sub>3</sub>, and 5 wt.% PP-MAH using a twin-screw extruder followed by injection molding. This research thoroughly investigates the mechanical and thermal characteristics. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR) results confirm the successful development of hybrid composites. The thermal stability, crystallization temperature, melting temperature, tensile strength, flexural strength, and impact resistance were evaluated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), universal testing machine, and low-velocity impact tester, respectively. The results indicated a significant improvement in the tensile strength of the PP matrix with the addition of GNPs, with the highest enhancement observed at 1.5 wt.% GNP loading, where the tensile strength reached a maximum of 40.54 MPa. This improvement was attributed to the proper interconnection, bonding, and compounding of PP with GNPs, thus leading to an increase in the load transfer efficiency.</p> </abstract>