Properties Of Polypropylene Matrix Research Articles

Influence of Surgarcane Bagasse Fibers with Modified Surface on Polypropylene Composites

ABSTRACTSugarcane bagasse fibers were pre-treated with sulfuric acid solution to improve the mechanical properties of polypropylene (PP) composites for automotive parts. It was used maleic anhydride grafted polypropylene (PP-g-MA) as coupling agent. Fibers were characterized by the techniques of scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. The chemical composition of fibers was also evaluated. PP was mixed to fibers, in proportions of 5 to 10% (wt/wt) using a thermokinetic mixer model MH-50H. Furthermore tensile specimens were prepared for evaluation of mechanical properties by tensile test. Pre-treatment fibers permitted the removal of other components from sugarcane bagasse. The chemical treatment reduced some of the fibers amorphous components, causing changes in their surface.The addition of pre-treated and compatibilizedfibers to PP matrix caused an increase in the elastic modulus in tensile. It was possible to obtain a more rigid and less deformable material with up to 10% fiber content. However, the use of the coupling agent showed results superior to other composites.

Fabrication of polypropylene blends with excellent low‐temperature toughness and balanced toughness‐rigidity by a combination of EPR and SEEPS

ABSTRACTTo overcome serious rigidity depression of rubber‐toughened plastics and fabricate a rigidity‐toughness balanced thermoplastic, a combination of styrene‐[ethylene‐(ethylene‐propylene)]‐styrene block copolymer (SEEPS) and ethylene‐propylene rubber (EPR) was used to toughen polypropylene. The dynamic mechanical properties, crystallization and melting behavior, and mechanical properties of polypropylene (PP)/EPR/SEEPS blends were studied in detail. The results show that the combination of SEEPS and EPR can achieve the tremendous improvement of low‐temperature toughness without significant strength and rigidity loss. Dynamic mechanical properties and phase morphology results demonstrate that there is a good interfacial strength and increased loss of compound rubber phase comprised of EPR component and EP domain of SEEPS. Compared with PP/EPR binary blends, although neither glass transition temperature (Tg) of the rubber phase nor Tg of PP matrix in PP/EPR/SEEPS blends decreases, the brittle‐tough transition temperature (Tbd) of PP/EPR/SEEPS blends decreases, indicating that the increased interfacial interaction between PP matrix and compound rubber phase is also an effective approach to decrease Tbd of the blends so as to improve low‐temperature toughness. The balance between rigidity and toughness of PP/EPR/SEEPS blends is ascribed to the synergistic effect of EPR and SEEPS on toughening PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45714.

Chemical treatment of cotton stalk and its effects on mechanical, rheological and morphological properties of Polypropylene/cotton stalk bio‐composites

Cotton stalk as commercially viable bio fiber for preparing bio‐composites is explored of late, and the effects of various chemical treatments of cotton stalk fiber on mechanical, rheological and morphological properties of Polypropylene (PP)‐Cotton stalk (CS) bio‐composites are reported in this study. PP‐CS bio‐composites were prepared by varying the amount of cotton stalk from 10 to 50% by melt mixing in twin screw extruder and then injection molded to make specimen. PP‐CS bio‐composites with 50 wt% untreated CS were found to have maximum improvement in tensile modulus (83%), flexural modulus (120%), impact strength (39%). Similar to tensile and flexural modulus, the storage modulus of the PP‐CS composites was also increased with incorporation of CS into the PP matrix. To further increase the interaction between CS and PP matrix, four different chemical treatments (alkali, silane, permanganate solution and stearic acid) were tested for mechanical properties of CS‐PP bio‐composites. Among them KMnO4 treatment was found most effective on overall enhancement of bio‐composite properties. Chemically treated CS‐PP bio‐composites could be an economic viable option to prepare high quality low cost composites for suitable applications in various interior parts of automotives and house hold products. POLYM. COMPOS., 39:E286–E296, 2018. © 2017 Society of Plastics Engineers

Hybrid multifunctional graphene/glass-fibre polypropylene composites

The effect of the simultaneous addition, using a melt-mixing procedure, of glass fibres (GFs) and graphene in the form of graphene nanoplatelets (GNPs) upon the properties of polypropylene (PP) has been studied in detail. Composite samples containing GFs and GNPs alone were also prepared for comparative purposes. The crystalline microstructure of the composites was characterised by X-ray diffraction (XRD), while scanning electron microscopy (SEM) was used to study the interface between the matrix and the fillers. The orientation of the glass fibres was evaluated using SEM while polarized Raman spectroscopy was utilized to determinate the orientation of the GNPs in the composite samples. The mechanical properties of the composites were evaluated by tensile testing and it was found that the Young's modulus of the hybrid material is higher than that of the materials containing the fillers individually, showing an additive effect. Raman spectroscopy employed simultaneously with deformation of the composites was used to show that there was good interfacial stress transfer between the PP matrix and the GNPs. Finally, the thermal conductivity of the materials was measured and found to be significantly higher for the composites containing GNPs alone.

The effects of carbon nanotubes, blend composition and glycidyl methacrylate-grafted polypropylene compatibilizer on the morphology, mechanical and electrical properties of polypropylene-polyamide 6 blends

The effect of multi-walled carbon nanotubes (MWCNTs) and a glycidyl methacrylate grafted polypropylene (PP-g-GMA) on the morphology, electrical and mechanical properties of polypropylene (PP), polyamide 6 (PA6) and their respective blends (PP/PA6), prepared by melt mixing, was investigated. The study of MWCNT nanocomposites from PP/PA6 blends is of significant interest, given that they combine the thermomechanical properties of PA6 with the processability of PP, resulting in materials with a wide range of mechanical and electrical properties. In this work, it was demonstrated that the addition of the same amount of MWCNTs to immiscible PP/PA6 blends produced nanocomposites with different morphologies, mechanical and electrical properties depending on the polymer proportion, and that the PP-g-GMA improved mechanical properties while preserving the electrical properties. SEM and TEM images showed that MWCNTs were comparatively better dispersed in PA6 than in PP; however, the addition of PP-g-GMA to PP matrix improved MWCNT dispersion. On the other hand, SEM micrographs showed different morphologies of PP/PA6 blends, depending on the composition of the polymers in the blend. The addition of PP-g-GMA to PP/PA6 blends and PP/PA6/MWCNT nanocomposites reduced significantly the domain size in both dispersed and continuous phases. Regardless of compatibilization, MWCNTs were located preferentially in the PA6 phase. The electrical characterization showed that PP/PA6/MWCNT nanocomposites exhibited lower volume resistivity values (108 Ω cm) compared to PA6/MWCNT nanocomposites (1011 Ω cm), at the carbon nanotube load employed, as a result of the confinement of the MWCNTs in the PA6 phase. The incorporation of PP-g-GMA to the PP/PA6 blends and PP/PA6/MWCNT nanocomposites did not cause a significant change in the volume resistivity of the blends; moreover, PP-g-GMA considerably improved the modulus and tensile strength of the PP/PA blends (i.e. up to 90 and 97 %, respectively for PP/PA 80/20 blend).

Fabrication of thermally expandable core–shell microcapsules using organic and inorganic stabilizers and their application

ABSTRACTThermally expandable core–shell microcapsules (TEM) were fabricated with an organic steric stabilizer and an inorganic Pickering emulsifier. In order to fabricate a TEM, acrylonitrile (AN) and metacrylonitrile (MAN) were used as monomers. Halloysite nanotubes (HNTs) and poly(vinylpyrrolidone) (PVP) were used as the inorganic Pickering emulsifier and the organic stabilizer, respectively. The liquid hydrocarbon content in the core, and the thermal and expansion properties, of TEMs with two different emulsifiers were compared. The mechanical properties of polypropylene (PP) foams containing TEMs prepared with two types of stabilizers were analyzed. The TEMs polymerized with PVP showed a finer expanded cell, while those fabricated with HNTs resulted in a larger expanded cell in the PP matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44247.

Crystallization, mechanical, and fracture behavior of mullite fiber‐reinforced polypropylene nanocomposites

ABSTRACTThis study describes the reinforcement effect of surface modified mullite fibers on the crystallization, thermal stability, and mechanical properties of polypropylene (PP). The nanocomposites were developed using polypropylene‐grafted‐maleic anhydride (PP‐g‐MA) as compatibilizer with different weight ratios (0.5, 1.0, 1.5, 2.5, 5.0, and 10.0 wt %) of amine functionalized mullite fibers (AMUF) via solution blending method. Chemical grafting of AMUF with PP‐g‐MA resulted in enhanced filler dispersion in the polymer as well as effective filler‐polymer interactions. The dispersion of nanofiller in the polymer matrix was identified using scanning electron microscopy (SEM) elemental mapping and transmission electron microscopy (TEM) analysis. AMUF increased the Young's modulus of PP in the nanocomposites up to a 5 wt % filler content, however, at 10 wt % loading, a decrease in the modulus resulted due to agglomeration of AMUF. The impact strength of PP increased simultaneously with the modulus as a function of AMUF content (up to 5 wt %). The mechanical properties of PP‐AMUF nanocomposites exhibited improved thermal performance as compared to pure PP matrix, thus, confirming the overall potential of the generated composites for a variety of structural applications. The mechanical properties of 5 wt % of AMUF filled PP nanocomposite were also compared with PP nanocomposites generated with unmodified MUF and the results confirmed superior mechanical properties on incorporation of modified filler. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43725.

Synthesis and characterization of magnetic nanocomposites for environmental remediation

In the present study, the effect of nano-magnetite (Fe3O4) content on mechanical and magnetic properties of polypropylene matrix is investigated. Magnetite nanoparticles were successfully synthesized by co- precipitation while the composites were prepared by an ex situ processing method involving solvent casting followed by compression molding. The nanoparticles and resulting nanocomposites were characterized by X- ray diffraction, thermogravimetric analysis, scanning electron microscopy, tensile testing and vibrating sample magnetometry. It was found that composites have tailorable mechanical and magnetic properties dependent on the content of magnetic filler. Increase of concentration of magnetite particles provides a significant increase of Young’s modulus without affecting the yield strength and the ductility. As regards the magnetic properties, nanocomposites having 10 wt% of nanoparticles exhibited a superparamagnetic behaviour that can be exploited in environmental applications.

Physical and Mechanical Properties of Polypropylene-Wood-Carbon Fiber Hybrid Composites

Effects of the addition of short carbon fibers (CFs) on the mechanical, physical, and morphological properties of polypropylene (PP) and wood-polypropylene composites (WPCs) were investigated. Hybrid composites (mix of wood and CFs) were manufactured in a two-stage process, pellet extrusion and samples mold injection with varying amounts of poplar wood fiber (0%, 20%, 30%, and 40%) and CFs (0%, 3%, 6%, and 9%), with and without maleic anhydride grafted PP (MAPP) as a coupling agent. The composites were prepared with extrusion blending followed by injection molding. The samples where then tested for mechanical and physical properties, and fractured surfaces where observed with scanning electron microscopy. The results indicated that the addition of CFs to WPCs improved the tensile and flexural strength and the modulus of elasticity but had only a small influence on elongation at break and impact strength. The density of hybrid composites slightly increased with CFs proportion but their water absorption was not affected. Scanning electron micrographs of the tensile fractured specimens showed improved adhesion of CFs and poplar with the PP matrix in the presence of a coupling agent.

Morphological studies and thermo‐mechanical behavior of polypropylene/sepiolite nanocomposites

This article describes the effect of natural Sepiolite nanofibers on the properties of polypropylene (PP) in the absence/presence of compatibilizer (maleic anhydride grafted‐polypropylene (PP‐g‐MA)). For this purpose, PP/Sepiolite and PP/PP‐g‐MA/Sepiolite nanocomposites were prepared by melt blending using twin‐screw extruder. The morphology and dispersion of Sepiolite in PP composites characterized using scanning electron microscope (SEM) and transmission electron microscope (TEM) revealed that the dispersion of Sepiolite in PP matrix was better in the presence of PP‐g‐MA. Thermogravimetric analysis (TGA) was used to study the effect of Sepiolite on the thermal stability of PP in absence/presence of PP‐g‐MA. X‐ray diffraction (XRD) and differential scanning calorimetric (DSC) techniques were employed to assess the effect of Sepiolite on the crystallinity of PP matrix. Dynamic mechanical analysis (DMA) was used to evaluate the viscoelastic properties of PP/Sepiolite nanocomposites in solid state. Mechanical properties evaluated as per ASTM methods showed ∼65% increase in flexural modulus, 60%–70% increase in tensile modulus and 10%–20% increase in impact strength on addition of 10% Sepiolite in PP. Addition of compatibilizer has further improved the flexural modulus close to 85% when compared to neat PP without compromising other properties like impact strength and tensile strength. POLYM. COMPOS., 38:E285–E294, 2017. © 2015 Society of Plastics Engineers

Effect of modifications of lignin on thermal, structural, and mechanical properties of polypropylene/modified lignin blends

Use of organic biomass, industrial waste lignin, was considered interesting due to its easy availability, polymeric nature, and ample scope to modify with an aim to replace conventional metal oxides to achieve improved properties of the blend when blended with polyolefins. To study the effect of chemical modification of lignin on the thermal, structural, and mechanical properties of polypropylene (PP)/modified lignin blends, purified industrial waste lignin was modified by two different chemical methods and blended in various proportions in PP matrix. The thermal stability of the blends was studied by thermogravimetric analysis, whereas melting and crystallization behavior of blends was studied by non-isothermal differential scanning calorimetry. The results show improved thermal stability of blends with increasing modified lignin proportion in the PP matrix. More depression in melting point was observed in PP/alkylated lignin blends than PP/arylated lignin blends, whereas addition of alkylated lignin shows polymorphism in PP matrix. Intermolecular interactions between blend components have been evaluated by applying several mathematical models to experimental mechanical property data. In most of the cases, good agreement has been obtained between the predictions made by using mathematical models and interpretations done on the basis of experimental data, showing the suitability of these models for predicting the mechanical properties of PP/modified lignin blends.

Effect of Clay Addition on the Properties of Carbon Nanotubes-Filled Immiscible Polyethylene/Polypropylene Blends

The effects of organically modified clay (OMC) incorporation on the microstructure and the electrical and mechanical properties of polypropylene (PP)/polyethylene (PE) blends filled with carbon nanotubes (CNT) were investigated. All blends were prepared by melt mixing in a batch mixer. The microstructures were characterized by scanning electron microscopy. In the OMC:CNT filled blends, the CNT were found to selectively localize within the PE phase, while the clay particles were observed in the PP phase. The electrical resistivity of OMC:CNT filled blends did not show any significant change as a result of the clay addition since it was localized in the CNT-free phase. On the other hand, the addition of clay degraded the blends' mechanical properties due to the poor adhesion between the OMC and the PP matrix.

Cryogenic Mechanical Properties of PP/MMT Polymer Nanocomposites

This article addresses the effect of Na+-Montmorillonite (MMT) on cryogenic mechanical properties of polypropylene (PP). Polypropylene/Montmorillonite (PP/MMT) nanocomposites were prepared by using twin-screw extruder incorporating the polypropylene grafted maleic anhydride (PP-g-mA) as compatibilizer is used for better dispersion of nanoclay in the polymer matrix. The dispersion and exfoliation of MMT in the nanocomposites were observed using transmission electron microscopy (TEM) and X-ray diffraction(X-RD). Mechanical behaviors of PP/MMT nanocomposites at both room temperature (RT) and liquid nitrogen temperature (77 K) were investigated in terms of tensile, flexural and impact properties. The mechanical results showed that the tensile strength of PP/MMT nanocomposites at both RT and 77 K reached the maximum at the 5wt. % MMT content, increased by 3.1% and 13.2%, respectively, as compared with those of pure PP sample. The notched impact strength at RT increased from 22.33 J/m for the pure PP matrix to 36.53 J/m for the nanocomposite with the 5wt% MMT content. The fracture surfaces of neat PP and PP/MMT nanocomposites were examined using Scanning Electron Microscopy (SEM). Finally, the dependence of the storage modulus and loss modulus of the MMT content was examined by Dynamic Mechanical Analyzer (DMA) at cryogenic temperature.

Cryogenic Mechanical Properties of PP/MMT Polymer Nanocomposites

This article addresses the effect of Na+-Montmorillonite (MMT) on cryogenic mechanical properties of polypropylene (PP). Polypropylene/Montmorillonite (PP/MMT) nanocomposites were prepared by using twin-screw extruder incorporating the polypropylene grafted maleic anhydride (PP-g-mA) as compatibilizer is used for better dispersion of nanoclay in the polymer matrix. The dispersion and exfoliation of MMT in the nanocomposites were observed using transmission electron microscopy (TEM) and X-ray diffraction(X-RD). Mechanical behaviors of PP/MMT nanocomposites at both room temperature (RT) and liquid nitrogen temperature (77 K) were investigated in terms of tensile, flexural and impact properties. The mechanical results showed that the tensile strength of PP/MMT nanocomposites at both RT and 77 K reached the maximum at the 5wt. % MMT content, increased by 3.1% and 13.2%, respectively, as compared with those of pure PP sample. The notched impact strength at RT increased from 22.33 J/m for the pure PP matrix to 36.53 J/m for the nanocomposite with the 5wt% MMT content. The fracture surfaces of neat PP and PP/MMT nanocomposites were examined using Scanning Electron Microscopy (SEM). Finally, the dependence of the storage modulus and loss modulus of the MMT content was examined by Dynamic Mechanical Analyzer (DMA) at cryogenic temperature.

Influence of Carbon Nanotubes on the Mechanical Properties and Morphology of the Thermoplastic Polymer Matrix of the Polyamide 6

This paper examines mechanical properties of composites with thermoplastic polymer matrix and carbon nanotubes. Polyamide 6 was used as a basic matrix, to which nanoparticles in the form of nanotubes were added in a described proportion to the weight. Granulate was prepared by cold granulation in the worm extruder. Dried granulate was injected into the Arburg injection molding machine. Mechanical properties were evaluated by tensile and hardness test. These results were then compared with results achieved by polyamide 6 to which no fillers were added. Discussion analyses what is the influence of nanotubes fillers on crystallinity degree of the polymer matrix of polyamide 6. Conclusion evaluates and compares influence of presence of fillers on the mechanical properties of polypropylene matrix.

Mechanical and thermal properties of polypropylene (PP) composites filled with modified shell waste

Shell waste, with its high content of calcium carbonate (CaCO3) plus organic matrix, has a potential to be used as a bio-filler. In this work, shell waste was modified by furfural and then incorporated to reinforce polypropylene (PP). The shell waste and modified powder were characterized by means of X-ray diffraction (XRD), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS), X-ray photoelectronic spectroscopy (XPS), and Fourier transformed infrared spectroscopy (FTIR). The mechanical and thermal properties of neat PP and PP composites were investigated as well. Thermal gravimetric (TG) analyses confirmed the reinforcing role of modified powder in PP composites. The mechanical properties studied showed that adding modified powder could significantly increase the impact strength, elongation at break point and flexural modulus of composites. The maximum incorporation content could reach 15wt.% with a good balance between toughness and stiffness of PP composites. Differential scanning calorimetry (DSC) results showed that the modified powder could act as a nucleating agent and thus increase the crystallization temperature of PP. Polarized optical microscopy (POM) observation also indicated that the introduction of modified powder could promote the heterogeneous nucleation of PP matrix.

Effect on modified nanoclay on dynamic mechanical and thermomechanical properties of natural fiber/polypropylene biocomposites

This study was conducted to investigate the effect of nanoclay addition on thermal and dynamic mechanical properties of polypropylene (PP) biocomposites reinforced with bleached red algae fiber (BRAF), kenaf fiber (KF), and cotton pulp fiber (CPF). The nano-biocomposites were fabricated with 40 wt.% loading of all natural fibers and addition of nanoclay at 5 or 10 wt.% loading by the melting compounding and compression molding techniques. The nanoclay effects on the thermal and dynamic mechanical properties of the biocomposites were analyzed as a function of properties of natural fibers such as chemical composition, fiber length, and surface morphology. Although the thermal decomposition temperature of nano-biocomposites decreased with the addition of nanoclay, the dimensional stability of biocomposites greatly improved with increasing nanoclay loading. Also, the dynamic mechanical properties of nano-biocomposites for the PP reinforced with BRAF, KF, and CPF were enhanced with the addition of 5 wt% nanoclay compared to those of biocomposites without nanoclay. The highest enhancement in dimensional stability was obtained for the nano-biocomposites reinforced with BRAF natural fiber. These increases can be attributed to a uniform distribution of nanoclay and to a good interfacial adhesion between the reinforcement and PP matrix. The well dispersed nanoclay particles can have good interactions with both natural fibers and polymer matrix, with the incorporation of the reinforcing natural fibers restricting the mobility of the polymer molecules resulting in the raised storage modulus values.

Characterization of melt‐compounded and masterbatch‐diluted polypropylene composites filled with several fillers

AbstractThe effect of various fillers on the mechanical, barrier, and flammability properties of polypropylene (PP) was studied. PP was filled with 4 wt% of nano‐sized calcium carbonate, titanium dioxide, organoclay, and multiwalled carbon nanotube (MWCNT). For comparison, micron‐sized calcium carbonate was also studied. Two‐step masterbatch dilution approach of the composites suggested no or only minor improvements in Young's modulus and tensile yield strength, whereas their ductility decreased compared to coupling agent‐modified PP matrix. The water vapor transmission results of filled films showed increased permeability compared to their coupling agent‐modified counterpart. Oxygen permeability, however, decreased for the composites. The MWCNT‐filled matrix showed the highest barrier and fire performance, attributed mainly to its higher filler volume content, but also other reasons such as the effect of filler dispersion, composite's thermal stability, and polymer crystallinity were discussed.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

Thermal and Mechanical Properties of Polypropylene/Boron Nitride Composites

The purpose of this study is to improve thermal conductivity and properties of polypropylene (PP) by adding functionality fillers. Boron nitride (BN) was used for improving the thermal conductivity of polymers. Two types of BN with different particle sizes were used. In addition, two types of PP with different viscosities were used as the polymer matrix. The thermal conductivity, storage modulus and loss modulus increased with the content of BN. The thermal conductivity of PP can be effectively enhanced by adding BN with large particles. Moreover, the melting temperature and crystallization temperature of PP/BN composites were larger than those of neat PP. The degree of crystallization of PP increased with BN. The effect of BN with small particles on the crystallization of PP was slightly stronger than that of BN with large particles. From the SEM observation, the agglomeration of BN with small particles was locally observed. In contrast, BN with large particles dispersed well in the PP matrix. This study found that BN with large particles effectively enhanced the thermal and properties of PP/BN composites. In addition, the above properties were independent of the matrix viscosity.

Polypropylene/date stone flour composites: Effects of filler contents and EBAGMA compatibilizer on morphology, thermal, and mechanical properties

This work aims to study the effects of date stone flour (DSF) on morphology, thermal, and mechanical properties of polypropylene (PP) composites in the absence and presence of ethylene-butyl acrylate-glycidyl methacrylate (EBAGMA) used as the compatibilizer. DSF was added to the PP matrix at loading rates of 10, 20, 30, and 40 wt %, while the amount of compatibilizer was fixed to the half of the filler content. The study showed through scanning electron microscopy analysis that EBAGMA compatibilizer improved the dispersion and the wettability of DSF in the PP matrix. Thermogravimetric analysis (TGA) indicated a slight decrease in the decomposition temperature at onset (Tonset) for all composite materials compared to PP matrix, whereas the thermal degradation rate was slower. Differential scanning calorimetry (DSC) data revealed that the melting temperature of PP in the composite materials remained almost unchanged. The nucleating effect of DSF was however reduced by the compatibilizer. Furthermore, the incorporation of DSF resulted in the increase of stiffness of the PP composites accompanied by a significant decrease in both the stress and strain at break. The addition of EBAGMA to PP/DSF composites improved significantly the ductility due to the elastomeric effect of EBAGMA. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013