Properties Of Polypropylene Research Articles

Synthesis and study of mechanical properties of polypropylene (PP)/banana nano-filler biocomposites

A novel sustainable biocomposite (Polypropylene/banana fiber) material was synthesized by using polypropylene (PP) reinforced with banana fibers (BF) with permeation of nano manganese oxide (MnO2). The different samples of the biomaterial were synthesized with varying percentages of PP, BF, and MnO2. The various mechanical properties of the developed biomaterial were studied by using suitable methodology. The maximum tensile strength is demonstrated with a fiber length of 15 mm and reinforcement of 20 % of banana fiber. The flexural strength increases with an increase in fiber loading up to 15 %, and then decreases. The ultimate flexural strength was achieved with a fiber length of 10 mm and a loading rate of 15 %. The absorption of impact energy is maximum with a fiber length of 15 mm and a loading rate of 20 %. Because of the improvement in mechanical properties with an increase in concertation of banana fiber up to a certain extent, it is concluded that this biomaterial can be used in various important applications after suitable treatment.

Influence of phosphorus-based flame retardants on polypropylene insulation for high-voltage power cable applications

For high voltage (HV) power cable applications, various studies have been performed to improve the mechanical and electrical properties of polypropylene (PP)-based insulation materials to replace crosslinked polyethylene. However, studies on the effect of additives to yield additional PP properties are still lacking. Herein, we prepared PP blends by melt-mixing widely used commercial flame retardants for PP with isotactic PP (iPP) and investigated their electrical breakdown, flame retardancy behaviors, and UV stability. Among the five kinds of flame retardants employed, aluminum hypophosphite (AHP), aluminum diethyl phosphinate, melamine pyrophosphate, ammonium polyphosphate (APP), and APP treated with silane, AHP was very effective in minimizing the decrease of the direct current breakdown strength of iPP at both 25 °C and 110 °C in the range of 5–20 phr. Particularly, only AHP afforded V-2 grade flame retardancy to iPP, and the flame retardancy was maintained even when the content was reduced to 3 phr. Furthermore, upon exposure to ultraviolet (UV) rays for 5 d, the tensile strength of pristine iPP decreased by approximately 44%, while that of a blend with 3 phr AHP decreased by only 10%. The study results will contribute to the optimization of power cable products through the use of appropriate flame retardants in the design of high-performance PP-based HV insulation materials.

Analysis of mechanical and thermal properties of polypropylene composite reinforced with Luffa cylindrica

Vegetable fibers have an economic potential to be employed as polymer reinforcement. This is due to their low cost, biodegradability, recyclability, adequate mechanical properties, and because they come from renewable sources. The growing need for alternative materials that meet the demands of various industrial segments (aerospace, mechanics, automobile, petrochemistry, shipping, civil engineering etc) requires detailed investigations on their physical, mechanical, and chemical properties. Detailed information about the behavior of fibers in a polymer matrix can indicate whether they can produce a structural composite. This work investigated the mechanical and thermal properties of polypropylene (PP) samples containing 0%, 10%, and 20% (w/w) Luffa cylindrica fibers, as well as to analyze the morphology of the fibers before and after their processing with the polymer. The mechanical results of the composites showed that those plant fibers reduced the strain of pure PP, increasing its stiffness. Thermogravimetric trials revealed that the composite had its thermal stability reduced with an increase in fiber content.

Comparison of Colour Properties of Polypropylene and Poly-(Lactic) Acid Fibres Dyed With Photoluminescent Dye

Abstract Every manufacturer wants to protect their textile products and their brand. A possible solution is, for example, the insertion of fibres with special pigments visible under irradiation by UV light into the final product. The paper focused on the study of the structure and colourimetric properties of polypropylene (PP) and poly-(lactic) acid (PLA) fibres modified with photoluminescent dye and halloysite (HNT) modified with photoluminescent dye. The photoluminescent dye and HNT modified with photoluminescent dye affected the structure of PP and PLA fibres differently. Increasing the HNT content up to 0.15 % increased the orientation of the PP fibres. In the case of PLA fibres, the increased content of photoluminescent dye in PLA fibres increased their orientation in the observed concentration area. PLA-based knitted fabrics showed better light stability, where there was no visible degradation of the knitted fabric, only its darkening. Likewise, PLA-based knitted fabric showed luminescence in UV light even after accelerated light aging.

Aromatic Compound Improving Polypropylene Film Performance for Power Capacitor in Magnetic Field

In this article, the dielectric properties of polypropylene (PP) films are investigated under 0–12-T magnetic field. The modification method based on aromatic compound blending is proposed to improve the performance of PP in the strong electromagnetic environment. Under the 12-T magnetic field, the dielectric constant declines from 2.34 to 2.27 at 1 kHz, and the dielectric loss grows up from 0.40% to 0.64% at 1 kHz. The leakage conductivity increases from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.56\times 10^{-{12}}$ </tex-math></inline-formula> to 1.85 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times \,\,10^{-{12}}$ </tex-math></inline-formula> S/m. The breakdown strength drops from 546.1 kV/mm under 0 T to 454.2 kV/mm under 12 T. The energy density of PP decreases from 3.09 to 2.07 J/cm3 due to the magnetic field. After blending with 0.05 wt% aromatic compounds, the dielectric properties of PP films got enhanced. The energy storage density of the modified films reaches 3.63 (under 0 T) and 2.72 (under 12 T) J/cm3 with enhanced voltage resistance and enlarged dielectric constant. This article is of significance to the application of PP capacitors under strong electromagnetic environment.

Mechanical and thermal degradation properties of Isotactic Polypropylene Composites with Cloisite15A and Cloisite20A

This work studies the influence of maleic anhydride grafted polypropylene (PP-g-MA) content on thermal and mechanical properties of polypropylene (PP) composites with two types of clays, differing modifier density in the interlayer space, Cloisite15A and Cloisite20A. PP/clay composites are melt blended in presence of different content of PP-g-MA from 3, 6, 9, and 12 wt.%. It is found that Cloisite15A with a high density of the modifier promotes the formation of intercalated structures, while Cloisite20A with a low density of the modifier, predominantly exfoliated nanocomposites are formed. In the first case, the structure tends to become intercalated whilst composites with Cloisite20A favor the formation of predominantly exfoliated structures. The formation of the nanocomposite is accompanied by a significant increase in thermal stability (50% weight loss is observed at temperatures of 360°C and 430°C for polypropylene and nanocomposites based on it, respectively). An analysis of the mechanical properties of nanocomposites generally indicates an increase in the elastic modulus by 15-20%, and this effect is more pronounced for exfoliated structures, the yield strength practically does not change and the elongation at break decreases noticeably.

Corrosion protection mechanisms of graphene oxide-reinforced polypropylene coating for mild carbon steel by advanced molecular dynamics simulations with emphasis on resistance to water and chloride ion penetration

Polypropylene can be used as a raw material for manufacturing corrosion-resistant coatings to protect the surface of the mild carbon steel substrate. To improve the properties of polypropylene (PP), graphene oxide (GO) can be added to the coating. In this research, molecular dynamics (MD) simulations were employed to evaluate the effect of GO additives on the PP coating using COMPASS Force-Filed of the Forcite module. The results of molecular modeling, such as mean square displacement (MSD), diffusion coefficient, concentration profile, and gyration radius (Rg), revealed that the permeability of corrosive agents, including water molecules and chloride ions in the composite coating (PP/GO), is much lower than pure one (PP). In addition, by reducing the surface energy from 77 to 68 mJ/m2, the water contact angle (WCA) is improved from 150◦ for the pure PP coating to 170◦ for the composite one. It can also be due to an 18% increase in system compaction in the presence of GO. In the other hand, the free fraction volume (FFV) in the presence of GO is reduced by about 4%. The adhesion of the coating to the mild carbon steel substrate has also been ameliorated by 38% for the PP/GO coating compared to the pure PP. Therefore, most of the simulated parameters reported the positive effects of compositing PP with GO.

The effects of TiO2 nanoparticles on the temperature-dependent electrical and dielectric properties of polypropylene

Nanoparticles are found to have the capacity to improve the specific properties of polypropylene (PP) for recyclable cable insulation material. However, previous studies have focused on the modification effect at room temperature, and few studies, on the nano-modification effect under high temperature environments. This article aims to study the effects of nanoparticles on the electrical and dielectric properties of PP at different high temperatures. Both TiO2 nanoparticles and PP/TiO2 nanocomposite samples are prepared in the laboratory by the wet chemical method and surface modification. Then, the AC and DC breakdown strength, conductivity, permittivity, and dielectric loss of the PP/TiO2 nanocomposite are measured at different temperatures. The results show that TiO2 nanoparticles introduce a small amount of charge traps into PP to restrain the conductivity and improve the breakdown strength of PP. But due to the additional interfacial polarization between TiO2 nanoparticles and the PP matrix, the permittivity and dielectric loss of the PP/TiO2 nanocomposite are enhanced, especially at low frequency.

Preparation of a cobalt metal-organic framework (Co-MOF) and its application as a polypropylene flame retardant by compounding with melamine polyphosphate

A cobalt metal-organic framework (Co-MOF) was successfully prepared, and its combination with melamine polyphosphate (MPP) was studied to enhance the fire retardant properties of polypropylene (PP) composites. The morphology, composition, and structure of PP/MPP/Co-MOF composites were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The maximum limiting oxygen index of the PP/MPP/Co-MOF composite was 26.8%, which is 49% higher than that of pure PP and its combustion grade reached the V-0 level. When 2 wt% Co-MOF was added, the carbon residue of the composite reached 19.6 wt%, peak heat release rate was significantly reduced, smoke emission was suppressed, fire growth index was significantly reduced, and the fire risk of the composite was effectively reduced. Analysis of the carbon residue showed that aggregated carbon spheres were present on the carbon residue surface of the composite material supplemented with Co-MOF. The generation of carbon spheres effectively prevented the heat exchange and release of combustible gas during the combustion of the composite material, significantly improving the flame retardancy and stability of the material. As a new material, MOF has great innovation and necessity in researching polymer flame retardant. Moreover, the latest composite materials synthesized in this paper contribute to environmental safety to a great extent.

Superior low-temperature mechanical toughness of the PP-based blown micro/nano layer films

The poor low-temperature mechanical properties of polypropylene (PP) film strongly restrict its applications in low-temperature service conditions like frozen packaging, or cold countries and regions. Here the PP-based films including 8-, 128- and 512-layer, were successfully produced by the self-developed nanolayered blown film technology. The 128-layer film exhibited exceptionally enhancement in the low-temperature mechanical properties, outperforming the commercialized 2-layer film with increments of 389%, 141%, and 126% in tensile impact strength, elongation at break, and tear strength, respectively. The DSC, WAXD, and SAXS results disclosed that the crystalline structure of PP in different micro/nano layer films was nearly identical. So, the ultrathin micro/nano layer structure should be responsible for the robust low-temperature mechanical properties, which dissipated energy during the mechanical break by promoting the large plastic deformation. Briefly, the PP-based micro/nano layer films fabricated by the self-developed nanolayer blown film technology show robust low-temperature mechanical properties, so this work may attract some attention in the polymer film industry.

Dual role of nanoclay in the improvement of the in-situ nanofibrillar morphology in polypropylene/polybutylene terephthalate nanocomposites

The present study has addressed the effects of nanoclay on the properties of polypropylene (PP)/polybutylene terephthalate (PBT) blend fibers such as their dyeability and, rheological and resiliency behaviors which are produced by melt spinning. The results of the differential scanning calorimetry (DSC) analysis indicated that the presence of both nanoclay and PBT significantly influenced the crystallinity of PP which also confirmed their nucleating effects on the nanocomposite fibers. Compared to neat PP fibers, the incorporation of 0.5–1wt.% of nanoclay and 10 wt.% of PBT nanocomposite fibers caused approximately 23% and 52% enhancements in the resiliency and dye uptake respectively without using toxic carriers. The rheological analysis was carried out for investigating the viscoelastic behavior, and microstructural and dispersion of nanoclay in the nanocomposite fibers. The rheological behavior in the small amplitude oscillatory shear (SAOS) test demonstrated the percolation threshold network of the structure of PBT fibrils in the PP matrix. When the PBT domains are fibrillated, the storage modulus (G′) and complex viscosity increase compared to neat PP. Also, the nonterminal behavior at low frequencies indicates the uniform dispersion of nanoclay in fiber nanocomposites. These all cause the improvement of the melt strength of the PP matrix. Transmission electron microscopy (TEM) was used to study the dispersion and localization of nanoclay. Nanoclay has also played a compatibilizing role in the immisible PP/PBT blend and was localized mainly in the PBT disperse and interface, and therefore prevented coalescence. The role of the compatibility of nanoparticles is to decrease the mean diameter of the nano-fibrils to 75 nm, for the hot-drawn nanocomposite fibers, as measured by scanning electron microscopy (SEM). All of the above lead to increasing the melt strength and elasticity of the nanocomposites in the fiber spinning process.

Prediction of the Elastic Properties of Ultra High Molecular-Weight Polyethylene Particle-Reinforced Polypropylene Composite Materials through Homogenization

In this study, to improve the mechanical properties of polypropylene (PP) with the objective of developing a composite with ultra-high-molecular-weight polyethylene (UHMWPE) as a reinforcement, the mechanical properties of the composite material were investigated via numerical analysis and finite element analysis (FEA). Based on a mathematical approach, the modulus of elasticity, shear modulus, and Poisson’s ratio were calculated using a numerical model, and, through FEA with application of the homogenization method, the elastic properties were predicted, and the results were comparatively analyzed. In the future, it will be necessary to compare experimental and numerical analysis results to verify the findings of this study.

Investigation on the mechanical, thermal, structural and morphological properties of polypropylene/ethylene-vinyl acetate copolymer/graphene oxide nanocomposites: effect of nanofiller surface functionalization and compatibilizers

Rubber toughened PP nanocomposites with desirable thermal properties and tensile strength (TS) found applications in automotive and packaging industries. This article reports on the mechanical, thermal, structural, and morphological properties of polypropylene (PP)/ethylene-vinyl acetate copolymer (EVA) blend reinforced with graphene oxide (GO) and silane-functionalized GO (f-GO). GO was modified with two silanes: γ-glycidoxypropyltrimethoxysilane (GPTMS) and γ-mercaptopropyltrimethoxysilane (MPTMS). The influence of three compatibilizer systems: (PP-g-OH, PP-g-COOH, and PP-g-NH2) on the properties of the composites was also evaluated. The structure and thermal behavior of GO and f-GO were comparatively studied for the first time. The attenuated total reflectance Fourier transform infrared (ATR-FTIR), Raman spectroscopy measurements, and X-ray diffraction (XRD) brought evidence for the successful interactions of silanes with GO. Thermogravimetric analysis (TGA) showed that f-GO exhibited higher thermal stability compared to GO. According to the mechanical analysis, PP/EVA/GPTMS-GO/PP-g-NH2 displayed higher TS and stiffness than the other compatibilized nanocomposites. TGA results indicated that the presence of both f-GO and compatibilizers caused a drastic improvement in the thermal stability. DSC analyses revealed that the addition of nanoparticles led to an increase in PP melting and crystallization temperatures, as well as the degree of crystallinity. XRD patterns revealed the formation of intercalated-delaminated nanocomposites and the promotion of β-phase crystals of PP for the samples containing PP-g-COOH and PP-g-NH2. The scanning electron microscopy (SEM) showed that the addition of compatibilizers drastically reduces the domain size of the EVA particles. All results suggest that GO nanoparticles enhance the mechanical and thermal properties of PP/EVA blend.

Improving the adhesion and properties in the material extrusion of polypropylene by blending with a polyolefin elastomer

We examine the effect of the thermorheological properties of polypropylene (PP) on its material extrusion characteristics using a 3D printer. Rheological characterization showed that PP with higher viscosity exhibited low extrusion rates during printing and suffered significant pressure drop. All PP grades tested suffered from warpage in the built structures, and debonding of individual strands under tensile deformation. Blending 20–40 wt% of an elastomeric ethylene-octene copolymer (EOC) with PP improved the flow properties and the interfacial fusion. Investigation into the morphology and thermal properties of the blends showed that owing to its amorphous structure and low melting point, the EOC dispersed phase facilitated the material extrusion process, reduced warpage, and promoted fusion between the printed strands, improving the mechanical properties.

Improved joint strength between friction-stir welded plates of Al alloy and thermoplastic vulcanizate

Nowadays, metal-polymer composites are used to reduce automobile's weight. However, welding nonpolar polymers to metals is difficult due to the lack of polar groups in molecular chains. The paper put forward an innovative strategy to solve this problem: by adding magnesium methacrylate (MDMA) changes the physical and chemical properties of polypropylene (PP)/ethylene-propylene-diene terpolymer (EPDM) TPV, which improves the compatibility of TPVs and metals. Moreover, the simulation experiments are carried out on plate vulcanization machine. It is found that the addition dosage and order of MDMA have a certain effect on the welding strength. Furthermore, friction stir welding (FSW) replicates the results of simulation experiments, and the ultimate tensile shear strength of P7-E3M1/aluminum alloy (AA6061-T6) reaches 24 MPa. Finally, the welding strength variation regularity with time shows that the properties of metal-TPVs become stable after 10 days. This work introduces a feasible and effective strategy that can be applied to weld various metals to polymers.

Enhanced adsorption of tetracycline on polypropylene and polyethylene microplastics after anaerobically microbial-mediated aging process

Aging of microplastics (MPs) can greatly affect their behaviors with other pollutants in aquatic and terrestrial ecosystems. Effect of anaerobically microbial-mediated aging on the physicochemical properties of polypropylene (PP) and polyethylene (PE) MPs was studied, then the adsorption behavior of tetracycline on the MPs was investigated. The results indicated that microbial-mediated aging process caused an increase in crystallinity and apparent changes in the morphology and surface structure of MPs. Visible pits and grooves on PP-MPs, as well as cavities and broken edges on PE-MPs were observed, while the surface functional groups also changed. Adsorption kinetics of tetracycline were well-described by a pseudo-second model. The equilibrium adsorption capacities of the microbial-aged PP- (MA-PP, 427.7 μg g−1) and PE- (MA-PE, 1095.3 μg −1) MPs were more than 3.8 and 8.1 times higher, respectively, than virgin PP- (V-PP, 111.7 μg g−1) and PE- (V-PE, 133.6 μg g−1) MPs. Adsorption isotherms of tetracycline on V-PP and V-PE were well-fitted by the Langmuir model, but failed to describe the adsorption process of tetracycline on MA-PP and MA-PE, suggesting changes in adsorption mechanisms of tetracycline due to anaerobic biodegradation of MPs. Solution pH had an evident effect on the adsorption capacity of tetracycline due to changes in both tetracycline speciation and surface charge of MPs. This study clearly suggests that anaerobically microbial-mediated aging process may greatly change the morphology and surface structures of PP-MPs and PE-MPs, and thus act as carriers for enhanced accumulation and transport of antibiotics in the environment, posing an increasing risk to ecosystem.

Effect of the amount of oxazoline compatibilizer on the mechanical properties of liquid crystalline polymer/polypropylene blends

Abstract The effect of the amount of 2,2′-Bis(2-oxazoline) on the spectral, thermal, morphological, and tensile properties of polypropylene (PP)/liquid crystalline polymer (LCP)/maleic anhydride grafted PP (PP-g-MAH) blends was investigated. A wholly aromatic LCP having a low melting point, namely a AL-7000 copolyester was used, because it also uses a compatibilizer with a low decomposition temperature. As the amount of 2,2′-Bis(2-oxazoline) increased, the dispersibility of the LCP improved and the tensile properties were improved, but when it was added in excess, a loss in function was observed. In particular, when 0.5 wt% of 2,2′-Bis(2-oxazoline) were added, the tensile strength and elastic modulus were the highest, and cohesive fracture (fracture within the matrix, not at the PP/LCP interface) was observed in the scanning electron microscope image.

Correlation Between Surface, Thermal, Mechanical and Morphological Properties of Polylactic Acid/Polypropylene and Polylactic Acid/Polyamide 6 Blends

In the automotive sector, which is one of the sectors where polymers are mostly used, their behaviour and compatibility in secondary processes such as painting and coating applications are important in the preference of polymers according to their usage areas as well as mechanical and thermal properties. In this context, it is known that surface wettability of a polymer material is of great importance for different application areas and it can be stated that wetting and non-wetting behaviours play an important role in the selection of polymers and their industrial applications. In this study, the contact angle properties of polypropylene (PP) and polyamide 6 (PA6), which are the most used polymers in the automotive sector and their polymer blends prepared by using polylactic acid (PLA) were examined. When PLA/PP and PLA/PA6 mixtures were compared, it was observed that there were significant differences in contact angle measurements and these properties detected in water contact angle measurements were attributed to changes in chemical structures, functional groups and morphology of related polymers. Surface analysis were supported by thermal, mechanical and morphological analysis and differences in static contact angle measurement results were explained.

Manufacturing and Modeling of Polypropylene-based Hybrid Composites by Using Multiple-Nonlinear Regression Analysis

In this research, artichoke stem particles (AS) and wollastonite (W) were used as an organic and inorganic fillers in order to improve the mechanical properties of polypropylene (PP). In this regard, PP-matrix composites containing AS and W were produced as non-hybrid and hybrid using a high speed thermo-kinetic mixer. Mechanical properties of polymer composites were investigated by the tensile test. Experimental results reveal that the highest modulus of elasticity was obtained in PP-W and the highest tensile strength was obtained in raw PP while the lowest ultimate strain value was obtained in PP-W-AS. Then, multiple-nonlinear regression analysis was employed to determine the effect of weight ratios of W and AS in PP on modulus of elasticity, tensile strength and ultimate strain. Experimental results were expressed with polynomial, rational and trigonometric models. The results show that the proposed models have well fitted with the experimental results. The coefficient of determination (R2) values were found between 0.95 and 1 in all models. Also, boundedness check control of the proposed models which gives information about whether models are realistic or not was carried out by calculating the maximum and minimum values produced by the relevant model.

Improving antistatic and mechanical properties of glass fiber reinforced polypropylene composites through polar adsorption and anchoring effect of organic salt

Matrix toughness and viscosity, fiber length, interface bonding, and crystalline structure play significant roles in tuning the antistatic and mechanical properties of polypropylene (PP) composites. However, there is no report available concerning the development of antistatic PP composites by considering all these factors. In this study, we fabricate antistatic long glass fiber reinforced polypropylene random copolymer composites filled with Li-TFSI (LGF/PPR/Li-TFSI) and explore how crystallization behavior due to Li-TFSI affects the interfacial strength and conductive mechanism. It is found that the polar effect promotes the adsorption of Li-TFSI on the surface of LGF to form a conductive track, and consequently, the three-dimensional conductive network formed by intertwined LGF effectively reduces the percolation threshold (i.e., 0.15 wt/wt%). Besides, the heterogeneous nucleation induced by Li-TFSI promotes the nucleation and crystal growth of PPR molecular chains on the surface of Li-TFS. Thus, Li-TFSI wrapped by spherulites improves the anchoring effect of the LGF on the PPR matrix. However, the anchorage degree is related to the close proximity of conductive particles, specifically, 0.05 wt/wt% Li-TFSI results in the highest level of stress transfer. Meanwhile, although the addition of 0.15 wt/wt% Li-TFSI causes a slight decrease in the interface strength, it leads to competitive nucleation between Li-TFSI and LGF, thereby generating thicker lamellae, which makes LGF/PPR/Li-TFSI the largest modulus. This study provides some new insights into the tailoring of material properties using Li-TFSI for antistatic PP composites.