Environmental damage promoted trough post‐consumer waste from the wood industry has worried the society, while its inadequate disposal has raised concerns of the scientific community. Environmentally ...and economically effective alternative is reusing this residue to produce smart composites. Therefore, this work aimed to investigate the performance of polypropylene (PP)/Jatobá Wood Powder (WP) composites compatibilized with ethylene propylene diene monomer rubber‐maleic anhydride (EPDM‐MA). The effect of distinct melt flow index (MFI) (PP H103 and PP H503) was also investigated. The composites were characterized using differential scanning calorimetry, thermogravimetry, mechanical properties (tensile, flexural, impact, and Shore D hardness), heat deflection temperature, Vicat softening temperature, water absorption and scanning electron microscopy (SEM). Addition of EPDM‐MA, increased impact strength. The best performance was observed for the composition with 10% EPDM‐MA and PP with lower MFI (PP H503). EPDM‐MA also decreased the water absorption for both PP, most due to the chemical interactions among composite phases. SEM images suggest encapsulation of wood particles by EPDM‐MA, promoting better composites performance. Reported results are valuable for the recycling industry, as well as are economically and environmentally promising.
Low‐density biopolyethylene (BioLDPE) ecocomposites added with particles of eggshell (ES) residue were produced using linear low‐density polyethylene grafted with maleic anhydride (LDPE‐g‐MA) as a ...compatibilizing agent. BioLDPE/ES and BioLDPE/ES/LDPE‐g‐MA compounds were processed in a twin‐screw extruder, and the specimens were injection molded. Torque rheometry increased and melt flow index reduced more prominently for the BioLDPE/LDPE‐g‐MA biocomposite with 20 phr ES, suggesting higher viscosity. Consequently, there was a higher level of ES particles breakdown, generating greater distribution and dispersion, as verified in optical microscopy and scanning electron microscopy images. This finding was supported by Fourier transform infrared spectroscopy, considering the intense absorption band at 871 cm−1 for BioLDPE/ES (20 phr)/LDPE‐g‐MA biocomposite, indicating a higher level of ES particles dispersion in BioLDPE matrix. Therefore, BioLDPE/ES (20 phr)/LDPE‐g‐MA biocomposite increased the elastic modulus, tensile strength, Shore D hardness, and heat deflection temperature by 51.4%, 16.9%, 16.4%, and 14, 6%, respectively, related to BioLDPE. Additionally, the flexibility was kept as seen in the elongation at break and impact strength, including not fractured during the impact test. Reported results for the biocomposites are valuable mainly for the polymer additive sector, since the ES has the potential to improve BioLDPE properties, expanding the range of applications.
Eggshell processing produced an ecologically based additive, with great potential for manufacturing biopolyethylene matrix composites.
Acrylonitrile‐EPDM‐styrene (AES) was applied as an impact modifier for poly(lactic acid) (PLA), and the combined effect of dicumyl peroxide (DCP) crosslinking and annealing heat treatment was ...investigated. Torque rheometry, melt flow index (MFI), mechanical properties (impact, tensile, and Shore D hardness), X‐ray diffraction (XRD), infrared spectroscopy (FTIR), heat deflection temperature (HDT), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were investigated. There was a considerable torque increment and fluidity drop in the PLA/AES/DCP blends caused by the crosslinking process and the formation of PLA‐g‐AES. Consequently, the impact strength and elongation at break properties improved. As an engineering terpolymer, AES was decisive in maintaining high elastic modulus, Shore D hardness, and HDT values. The PLA/AES/DCP (0.8 phr) composition leaned towards a synergism of mechanical properties, gaining 505.6% and 264.8% in impact strength and elongation at break, respectively, compared to neat PLA. FTIR and XRD analysis revealed high crystallinity, with samples presenting large crystals. The higher crystallinity had a deleterious effect on the mechanical properties of the PLA/AES/DCP blends. However, there was a marked improvement in HDT and higher toughness compared to PLA. The results before and after annealing the PLA/AES/DCP (0.8 phr) blend are promising for constructing new semi‐biodegradable materials for additive manufacturing.
The crosslinking of the PLA/AES blend with dicumyl peroxide in the molten state formed a tough material, suggesting the formation of PLA‐g‐AES.
Herein, we prepared toughened and electrical nanocomposites of polyamide 6 (PA6)/acrylonitrile‐butadiene‐styrene (ABS) compatibilized with maleic anhydride‐grafted acrylonitrile‐butadiene‐styrene ...(ABS‐MA). Functionalized multi‐walled carbon nanotubes (MWCNTf) were used as conductive nanofillers. Nanocomposites were processed in an internal mixer and injection molded. Torque rheometry, impact strength, elastic modulus, heat deflection temperature (HDT), differential exploratory calorimetry (DSC), melting and crystallization kinetic curves, electrical conductivity, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were evaluated. Torque increased with the MWCNTf content in the PA6/ABS/ABS‐MA/MWCNTf nanocomposites, suggesting an increase in viscosity. The MWCNTf were well dispersed in the nanocomposites, generating an electrical percolation path. The impact strength of the PA6/ABS/ABS‐MA/MWCNTf nanocomposites was superior to that of pure PA6, indicating improved flexibility and toughness. The addition of 1 pcr of MWCNTf in the PA6/ABS/ABS‐MA system was sufficient for antistatic application, with a 221% higher impact strength, compared to pure PA6. The DSC studies showed that the crystallization temperature of the nanocomposites shifted to higher temperatures. This was due to the MWCNTf that accelerated crystallization. Additionally, the nanocomposites HDT increased by 20°C compared to the PA6 matrix, suggesting a superior thermomechanical strength. The developed nanocomposites show improved mechanical, electrical, and thermomechanical properties. Therefore, they exhibit great technological potential for application in antistatic packaging.
Schematic representation of the preparation of electrical and toughed nanocomposites.
The development of new ecological materials to promote sustainability is being encouraged. Crosslinked biopolyethylene (BioPE)/noni flour (Morinda citrifolia) biocomposites were prepared using maleic ...anhydride‐grafted polyethylene (PE‐g‐MA) and dicumyl peroxide (DCP). The biocomposites were processed in an internal mixer and injection molded. Torque rheometry, Izod impact strength, tensile strength, heat deflection temperature (HDT), differential scanning calorimetry (DSC), thermogravimetry (TG), and scanning electron microscopy (SEM) properties were investigated. Torque rheometry curves suggest that the biocomposites did crosslink due to the DCP attack on the BioPE chain. The BioPE/noni flour/PE‐g‐MA formulation with 0.5% and 1% DCP produced a higher level of crosslinking. As a result, the mechanical properties (impact strength, elastic modulus, and tensile strength) were improved. SEM showed fractured noni flour particles in the BioPE matrix with the formation of a tubular structure. The HDT increased, suggesting that the biocomposites exhibit enhanced thermomechanical strength. Furthermore, the biocomposites thermal properties obtained by DSC underwent few modifications. The TG results showed that the crosslinked biocomposites have better thermal stability than the noncrosslinked biocomposites. The crosslinking process of BioPE/noni flour biocomposites with the PE‐g‐MA/DCP hybrid is an effective way to improve the performance of these materials.
Illustrative scheme of noni flour preparation. Noni flour has the potential to be used as a natural filler, aiming at the production of ecological composites.
The present investigation aimed to produce ecological composites of biopolyethylene (BioPE) with macaíba shell (MS), using polyethylene‐graft‐maleic anhydride (PE‐g‐MA) and polyethylene‐graft‐acrylic ...acid (PE‐g‐AA) as compatibilizers, as well as macaíba almond oil as a plasticizing agent. The composites were processed in a co‐rotational twin‐screw extruder and injection molded. The addition of 30% by weight of MS in the BioPE matrix caused a reduction in impact strength and elongation at break, but improved stiffness and heat deflection temperature. The PE‐g‐MA and PE‐g‐AA compatibilizers improved the impact strength of the composites, suggesting increased interactions between the phases. There was an increase in the composites degree of crystallinity, indicating that the MS acted as a nucleating agent. The macaíba oil addition to the composites increased the impact strength, indicating a plasticizing effect. However, the elastic modulus, tensile strength, and degree of crystallinity tended to decrease. In general, the use of PE‐g‐MA compatibilizer was more effective to improve the composites mechanical properties. The reuse of MS is feasible for the production of sustainable composites.
The postconsumer waste of vulcanized styrene–butadiene rubber (SBRr) is a raw material rich in additives with potential reuse in the plastics processing industry. The present investigation evaluated ...the effectiveness of styrene–ethylene/butylene–styrene copolymer (SEBS) in the compatibilization of biopolyethylene (BioPE)/SBRr blends. The blends were processed in a twin-screw extruder and injection molded to evaluate the melt flow index (MFI), impact strength, tensile strength, Shore D hardness, thermogravimetry (TG), differential scanning calorimetry (DSC), and heat deflection temperature (HDT). Morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The BioPE/SBRr/SEBS blend (70/20/10 wt%) showed the lowest MFI, which indicates a higher viscosity and, consequently, higher compatibility that led to increments of 120% and 698.6% on impact strength and elongation at break, respectively, compared to the noncompatibilized system. The reduction in elastic modulus, tensile strength, and Shore D hardness confirmed the increased flexibility of the BioPE/SBRr/SEBS blends. Melting and crystallization properties of the polymer blends were comparable to the BioPE matrix, suggesting that 20 wt% SBRr content did not severely deteriorate the thermal behavior. SEM analysis showed that SEBS induced a morphology with extensive plastic deformation, confirming the high impact strength and elongation at break. BioPE/SBRr blends compatibilized with SEBS offer significant technological potential, indicating that SBRr can be introduced into the productive chain and contribute to sustainability.
Antistatic packaging has gained great importance for protecting sensitive electronic devices against static charges. In this work, polyamide 6 (PA6)/carbon nanotubes (MWCNT) nanocomposites were ...developed in the molten state, aiming to evaluate the potential for dissipation of static charges. The properties of torque rheometry, melt flow index (MFI), mechanical (impact, tensile, and Shore D hardness), Raman spectroscopy, electrical conductivity, differential scanning calorimetry (DSC), thermogravimetry (TG), and scanning electron microscopy (SEM) were investigated. In the Raman spectra of the nanocomposites, the main MWCNT bands were observed at 1347 cm
−1
and 1580 cm
−1
, confirming the distribution in the PA6 matrix. Incorporating 5 phr (parts per hundred resin) of MWCNT into the PA6 matrix promoted better distribution, as verified in the storage module and scanning electron microscopy (SEM). In addition, there were gains in elastic modulus, Shore D hardness, and heat deflection temperature (HDT) by 11%, 4.5%, and 12.3%, respectively, in relation to PA6. Differential scanning calorimetry (DSC) indicated an increase in the crystallization process for all PA6/MWCNT nanocomposites, while an increase of 9.4 °C was verified in thermal stability by thermogravimetry for PA6/MWCNT (5 phr). From the point of view of the potential for antistatic application, the PA6/MWCNT (5 phr) nanocomposite presented electrical conductivity in the order of 1.1 × 10
–06
S/cm, an adequate value for dissipating static charges. In view of this, the tailor-made PA6/MWCNT (5 phr) nanocomposite has the potential for antistatic protection.
The mixing protocol effect was investigated in nanocomposites based on polyamide 6 (PA6) and maleic anhydride grafted ethylene‐propylene‐diene (EPDM‐MA), using Ni‐Zn ferrite as filler. The ...nanocomposites were processed using an internal mixer and specimens were injection molded. Compounds properties were investigated through Izod impact strength, tensile strength, x‐ray diffraction (XRD), magnetic measurements, differential scanning calorimetry (DSC), thermogravimetry (TG), heat deflection temperature (HDT), and scanning electron microscopy (SEM). PA6/EPDM‐MA mixture showed super‐tough behavior, with an increase of around 918% in impact strength, compared with PA6. However, there was a loss close to 50% in the elastic modulus and 5% in HDT, due to the high flexibility. In view of this, this mixture was selected for the production of nanocomposites toughened with Ni‐Zn ferrite, using three mixing sequences. When the nanocomposite was processed by the simultaneous mixing of all components (PA6/EPDM‐MA/Ni‐Zn), the highest impact strength (458 J/m) was reached, corresponding to a gain of 486%, compared with PA6. On the other hand, when Ni‐Zn ferrite and PA6 were initially premixed by melting, before EPDM‐MA addition in a second processing step, HDT and impact strength properties increased by 6% and 281%, in relation to PA6. In addition, the nanocomposites showed magnetic responses, with a soft material behavior, that is, they magnetize and demagnetize easily. In general, toughened and magnetic nanocomposites were produced, with good mechanical and thermal properties, displaying potential to produce magnetic films.
Polypropylene/Syagrus Cearensis fiber composites compatibilized with polypropylene‐graft‐maleic anhydride (PP‐g‐MA) and styrene(ethylene‐butylene)‐styrene copolymer (SEBS‐g‐MA) were successfully ...produced using a co‐rotating twin‐screw extruder followed by injection molding. The composites were characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The mechanical properties were determined by Izod impact and tensile testing. Thermal properties were obtained by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Heat deflection temperature (HDT) was determined to study the thermomechanical properties of the composites. XRD and DSC indicated the presence of two polypropylene polymorphs: α and β. The unmodified PP/Fiber composites showed an incompatible behavior, presenting low fiber/matrix interaction and poor interfacial adhesion. The poor compatibility led to low elongation at break and impact strength but high tensile strength. PP‐g‐MA coupling agent promoted some adhesion to the PP/fiber interfaces but not enough to improve the impact strength. The composites with PP‐g‐MA exhibited improved tensile modulus and strength. The enhanced PP/fiber interfacial interaction promoted by SEBS‐g‐MA generated a better interplay of mechanical properties, improving impact strength and elongation at break while preserving the elastic modulus and tensile strength. In general, the fibers enhanced the thermomechanical stability of PP, as evidenced by higher HDT values.
