Maleic Anhydride-grafted Polypropylene Research Articles

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.

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.

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 25phr 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.

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.

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>

Examination Of Perlite-Polymer Interface Interactions in Polypropylene-Based Composites via Several Compatibilizers

The surface interaction between the polymer and the mineral additive is one of the most significant aspects influencing the efficiency of mineral-filled polymeric composites. In this work, three distinct compatibilizers were introduced to composites based on polypropylene (PP) and perlite to improve interactions between the constituents. On composites comprising 10% expanded perlite content, three different ratios of ethylene vinyl acetate copolymer (EVA), thermoplastic polyurethane elastomer (TPU), and maleic anhydride grafted polypropylene (MA-PP) compatibilizers were employed. Composites were produced using an approach designated melt blending followed by injection molding. The composites containing MA-PP compatibilizer possessed the most outstanding performance, according to the results of mechanical, physical, and dynamic mechanical evaluations and morphological characterizations. The investigated aspects indicated a rise in the composites containing 10 percent compatibilizer with the lowest adding amount, whereas performances declined at high compatibilizer contents. Along with these results, it was determined that the compatibilizers included in the PP/perlite composite system assisted in the fabrication of the composites by promoting the force values and melt flow rates identified during melt mixing. Following the test outcomes, MA-PP performed better than TPU and EVA in terms of compatibilizer efficiency. In general, it has been revealed that the selection of MA-PP compatibilizer in the manufacturing stages would offer benefits in terms of both simplicity of processing and mechanical strength where expanded perlite will be adopted as a natural filler for PP-based composites.

Mechanical Properties of Rice Husk-Recycled Polypropylene Composite

The growing amount of plastic and food waste has become a serious problem around the worldwide. As a byproduct of milling rice, rice husk is an agricultural waste that is produced in bulk quantities. Rice husk has been used as filler in polymer composites in a variety of ways. However, there have only been a few reports of using rice husk as reinforcement in composites made of recycled polypropylene. The limited interfacial reaction between natural fibre and polymer is the fundamental issue in natural fibre-based composites. This prompted the development of sustainable composite manufactured from recycled polypropylene(rPP) and rice husk (RH). Thus, we investigated the intermolecular adhesion between rPP–RH composite with maleic anhydride grafted polypropylene (MAPP) as a coupling agent. Varied compositions of RH in the range of 10–40 wt% with 4 wt% of MAPP were fabricated. The rPP, RH and MAPP were blended and executed in injection moulding. The mechanical properties will be analysed through differential scanning calorimetry, rheology, tensile, flexural, impact and hardness tests. The result shows RH agglomeration and limited dispersion in the composite cause a reduction of up to 40% for tensile strength compared to neat rPP. Despite this, it demonstrates improvements in tensile modulus, flexural modulus, impact, and hardness. It is evidence of a good intermolecular between rPP matrix and RH. In conclusion, the ideal RH loading for composites occurs at a fillercontent of 40% and has acceptable mechanical properties for various composite applications.

Morphological characteristics of spray dried cellulose nanofibers produced using various wood pulp feedstocks and their effects on polypropylene composite properties

Bleached Kraft pulp (BKP), unbleached Kraft pulp (UKP), and old corrugated cardboard pulp (OCC) are excellent feedstock sources for producing CNF suspensions manufactured by a mechanical disk refining process. The CNF drying operation should be performed to produce dry powders that can be compounded into thermoplastic matrices, and spray drying is fast, simple, cost-effective, and scalable. Among several spray-drying techniques, the pilot scale-rotary disk atomizer has many advantages, including large capacities, drying efficiency, and less feed blockage. In this study, BKP, UKP, and OCC pulps fibrillated to 90 % and 100 % fines levels were spray-dried using a pilot-scale rotary disk atomizer. The high-quality micrometer scale, round-shaped powders were produced from all feedstock sources, and a smaller particle size powder was produced with the higher fibrillated pulps. The spray-dried cellulose nanofibrils (SDCNFs) were compounded into a polypropylene (PP) matrix as a reinforcing material, and maleic anhydride-grafted polypropylene (MAPP) was used as a coupling agent. A masterbatch was used for the optimal dispersion and distribution of SDCNFs and MAPP in the PP matrix. It was concluded that the tensile and flexural properties increased as the particle size of SDCNFs increased, and the impact strength increased as the particle size decreased. The tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength increased by up to 29 %, 66 %, 15 %, 27 %, and 11 % respectively, compared to the neat PP after adding 10 wt% of SDCNFs with MAPP to the PP matrix.

Glycerol-treated polypropylene/carbon black nanocomposites: Analysis of electrical, rheological, thermal and mechanical properties

Electrically conductive nanocomposites based on polypropylene (PP) were prepared using carbon black (CB) nanoparticles via melt blending in the presence of glycerol and castor oil as hydroxyl functional dispersing aids and maleic anhydride–grafted polypropylene (MAgPP) as a compatibilizer. Initially, electrical conductivity of PP/CB nanocomposites with different dosages of both CB nanoparticles and dispersing aids were investigated through electrical analysis. Results indicated that castor oil had no beneficial effects on electrical conductivity. However, the efficiency of 3 wt% loading of glycerol was verified through measurements of electrical, rheological, thermal and mechanical properties as well as by morphological studies. The volume electrical conductivity value of PP nanocomposites containing 12 wt% CB significantly enhanced to 1.2 × 10−4 S/cm by adding 3 wt% glycerol in compared with nanocomposite without glycerol with the volume conductivity value of 1.8 × 10−6 S/cm. Incorporation of optimum amount of glycerol favoured the dispersion of nanofiller in the matrix which was confirmed by scanning electron microscopy observations, leading to higher conductivity due to better formation of conductive pathways within the matrix. Additionally, at the same concentration of CB nanofiller, samples treated with 3 wt% glycerol showed higher melting temperatures, storage modulus ( Gˊ), complex viscosity, tensile modulus and elongation at break. These findings indicate that adding an optimum amount of an efficient hydroxyl functional component like glycerol into PP/CB nanocomposite can be a promising way to enhance the electrically conductive performance while other properties could be maintained well or even improved.

TENSILE STRENGTH AND HARDNESS OF POLYPROPYLENE-BAMBOO/KENAF HYBRID COMPOSITE AFTER OPTIMIZATION OF PRODUCTION PROCESS

While in use and when not, engineering materials occasionally exhibit poor characteristics and perform poorly as a result of internal or external factors. Therefore, there is a need to improve the protection of the composites from the various agents and improve their mechanical properties. This study's objective was to assess the impact of bamboo/kenaf hybrid fibres, Maleic Anhydride Grafted Polypropylene (MAHgPP), Hinder Amine Light Stabiliser (HALS), and Calcium Carbonate (CaCO3) additions on tensile strength and hardness at various levels, as well as their interactions on polypropylene (PP) composites. The manufacturing of the composites was accomplished through the compression molding process. The study was conducted using Taguchi orthogonal array L27 with fiber, MAHgPP, HALS, and CaCO3 as input parameters. A robust optimization technique for product and process design (Taguchi method ) was used to optimize the parameter settings for the tensile strength and hardness of the composite. Results showed that the tensile strength of the resultant composite ranged from 37.60 MPa to 53.57 MPa; while the hardness value ranged from 70.32 (Shore A) to 93.03 (Shore A). The optimized composite had a tensile strength of 49.12 MPa and a hardness of 79.85 (Shores A). The factors settings that gave the combined optimum tensile strength and hardness for the bamboo/kenaf fiber are 36.87% fiber, 5% MAHgPP, 1% HALS, and 3% CaCO3. therefore the best tensile strength and hardness performance of the composite was obtained from the optimum setting.

Compatibilizing effect of grafted recycled graphene on the viscoelasticity and mechanical performance of polypropylene composites

The interface problem encountered with the graphene addition in polyolefin composites is an important issue and it is necessary to use various compatibilizers to overcome this problem. Maleic anhydride grafted Polypropylene (MAPP), which is an extensively used compatibilizer in PP composites tends to eliminate these interfacial problems by interacting physically through PP chains and allows easier stress transmission from matrix to reinforcer. However, there is a lack of understanding about how this compatibilizer works with graphene-based PP composite systems since MAPP is mostly used to harmonize hydrophilic surfaces of fillers with non-polar PP. With this study, instead of direct usage of MAPP and GNP separately, waste tyre driven graphene nanoplatelets (GNP) was grafted by MAPP and the resulted material (MAPP-g-GNP) was compounded with PP by applying high shear rates at a melt phase. Effect of MAPP-g-GNP on the processability, viscoelastic response, and mechanical performance of PP composites were investigated, and high degree of interfacial enhancement was achieved by chemically combined MAPP with amphiphilic type of GNP in PP matrix. The use of MAPP-g-GNP at a loading ratio of 0.1 wt% resulted in 38% increase in flexural modulus and 26% in flexural strength and tensile modulus compared to neat PP. The two additives used in the PP composite (2 wt% MAPP and 0.1 wt % GNP) were reduced to a single additive (PP/MAPP-g-GNP) with a 95% weight reduction in the additive content of PP. Rheological studies support that MAPP is not as successful as MAPP-g-GNP in strengthening the interface when used alone with GNP due to the lower complex viscosity and the higher crossover frequency. This study contributes to the production of high-performance PP materials with a very low amount of combined GNP and compatibilizer by integrating the circularity approach in compound development by using GNP obtained from recycled and upcycled waste tyres.

Preparation of Rechargeable Antibacterial Polypropylene/N-Halamine Materials Based on Melt Blending and Surface Segregation.

Polypropylene (PP) has been widely used in health care and food packaging fields, however, it lacks antibacterial properties. Herein, we prepared the polymeric antibacterial agents (MPP-NDAM) by an in situ amidation reaction between 2,4-diamino-6-dialkylamino-1,3,5-triazine (NDAM) and maleic anhydride grafted polypropylene (MPP) using the melt grafting method. The effects of reaction time and monomer content on the grafting degree of N-halamine were investigated, and a grafting degree of 4.86 wt % was achieved under the optimal reaction conditions. PP/MPP-NDAM composites were further obtained by a melt blending process between PP and MPP-NDAM. With the adoption of surface segregation technology, the content of N-halamine structure on the surface of PP/MPP-NDAM composites was significantly increased. The antibacterial tests showed that the PP/MPP-NDAM composite could achieve 99.9% bactericidal activity against 1.0 × 107 CFU/mL of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 10 and 5 min of contact, respectively. The antibacterial effect became more pronounced with the prolongation of chlorinated time, and it could achieve 99.9% bactericidal activity against E. coli within merely 1 min of contact.

Tuning the electromagnetic interference shielding performance of polypropylene cellular nanocomposites: Role of hybrid nanofillers of MXene and reduced graphene oxide

Electromagnetic interference (EMI) is deemed a disruptive influence on electronically-operated devices and human health, which can cause catastrophic and sometimes irreversible damage. To mitigate such a hindrance, cellular-based polymer nanocomposites, comprising conductive nanofillers, are considered a viable solution and have been shown to exhibit significant potential due to absorption dominancy of EM waves. Herein, we designed both solid and cellular nanocomposite based on polypropylene grafted maleic anhydride (PP-g-MA) comprising various contents of single MXene, as well as hybrid MXene/reduced graphene oxide (MXene/rGO) nanolayers and investigated their EMI shielding performance to systematically assess the influence of hybridization. The influence of including MXene and rGO on microstructure and morphology of PP nanocomposite foams was evaluated, and a correlation between microcellular structure and nanofiller loading was established. Electrical conductivity test showed an increase of conductivity in both types of nanocomposite samples comparing to the pristine PP. A considerable improvement resulted in the EMI shielding effectiveness (EMI SE) of solid hybrid samples at a constant weight percentage of 7 wt% using a 2:1 ratio of MXene to rGO compared to a sample comprising a 1:1 ratio of the nanofillers. When the MXene:rGO content was 10 wt.%, SEA contributed to SET by 83%, while for the cellular nanocomposites, SEA's contribution to SET raised to 92%. Finally, an appropriate improvement occurred in the case of compressive strength of both single- and hybrid-incorporated nanocomposites as a result of robust interactions between the fillers and PP chains. The present study demonstrates that the fabricated hybrid cellular system can act as a successful EMI shielding material, and can stand as a potential candidate for various EMI shielding applications.

Straightforward Strategy Toward In Situ Water-Phase Exfoliation and Improved Interfacial Adhesion to Fabricate High-Performance Polypropylene/Graphene Nanocomposites.

Graphene is a potential candidate for achieving high-performance and multifunctional polypropylene (PP) composites. However, the complex manufacturing process and low dispersibility of graphene, as well as poor interfacial adhesion between graphene and polypropylene chains, stifle progress on large-scale production and applications of graphene/polypropylene composites. Here, we develop a strategy of maleic anhydride grafted polypropylene (MAPP) latex-assisted graphene exfoliation and melt blending to address the key challenges facing in industrial production. The surface property of the graphitic precursor is well-designed to achieve a high graphene exfoliation yield of ∼100% and induce abundant hydrogen bonding between the obtained mild-oxidized graphene (MOG) sheets and MAPP chains. Therefore, the MAPP-modified MOG can homogeneously disperse in the PP matrix and exhibits an excellent interfacial compatibility with the polymer. The addition of 5 wt % MOG results in simultaneous increase in the initial decomposition temperature, crystallization temperature, tensile strength, and Young's modulus by 43.2, 11.4 °C, 21.5, and 50.7%, respectively, and the electrical conductivity increases to 0.02 S·m-1. This work illustrates a practical solution to low-cost, eco-friendly, and feasible industrial production of graphene/PP composites through synchronous exfoliation and interfacial modification of graphene.