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By incorporating nanomaterials into polymer matrices, nanocomposites can be produced with enhanced properties, combining the ease of processing thermoplastics with the superior physical characteristics of nanoparticles. In this study, fully bio‐based polyamide 1010 was used as the polymer matrix, with graphene oxide (GO), hexagonal‐boron nitride (h‐BN), and molybdenum disulfide (MoS2), both individually and in hybrids, serving as fillers. The tensile behavior of these nanocomposites was evaluated at room temperature and −40 °C, along with their morphology and microstructure. Results showed that the nanomaterials slightly shifted the polymer's crystallization temperature upward, indicating a small nucleating effect, but also hindered the development of crystalline domains, reducing the crystallization kinetics. Despite no change in the final crystalline form, nanocomposites with h‐BN and MoS2 showed lower microstructural order as evidenced by XRD. Regarding tensile behavior, GO provided the greatest toughening at room temperature due to its larger lateral dimensions and good chemical affinity with the matrix. However, at low temperatures, h‐BN‐based nanocomposites maintained the toughening effect better than GO‐based ones. This can be attributed to the lower order of the polymer's semi‐crystalline structure promoted by h‐BN, allowing greater energy dissipation. Surprisingly, hybrid fillers did not exhibit synergistic effects, with one nanomaterial hampering the effect of the other. However, SEM analysis indicated that the fracture mechanisms of the nanocomposites remained unchanged from the neat polymer, which makes them interesting options for applications that require desirable mechanical properties at a wide temperature range. Highlights: GO showed the best toughening of polyamide 1010 at room temperature.Toughening at room temperature is mainly due to nanomaterials physical traits.Most nanofillers lowered polyamide's overall microstructural order.Toughening at −40 °C is mainly due to lower microstructural order. [ABSTRACT FROM AUTHOR]

In recent years, the demand for environmentally sustainable materials has led to the exploration of biodegradable composites as alternatives to fossil‐based polymeric matrices. Among these, poly‐ε‐caprolactone (PCL) has emerged for its versatility and broad applicability. However, challenges such as limited mechanical strength and thermal stability demand innovative approaches for enhancement. This study focuses on the development and characterization of hierarchical composites of PCL, ramie fibers, and graphene oxide (GO) to address these challenges. Differential scanning calorimetry (DSC), x‐ray diffraction (XRD), contact angle, surface energy, mechanical properties (impact and tensile), scanning electron microscopy (SEM), and ecotoxicity assays were employed for evaluation. Results indicate that the inclusion of GO and ramie fibers alters the thermal properties, increasing melting enthalpy and crystallinity due to GO's nucleating effect and fiber‐induced steric hindrance. Increased hydrophilicity and surface free energy suggest enhanced biodegradation potential. Ecotoxicity tests confirm non‐toxicity, while SEM reveals low interfacial adhesion between the fiber and matrix. Tensile tests reveal no synergistic effects, although GO enhances biodegradation without compromising mechanical integrity. The presence of GO and ramie fibers does not induce toxicity, as evidenced by normal seedling growth. While hybridization does not significantly impact mechanical properties, GO offers avenues for enhancing biodegradability and expanding ramie fiber applications. This study highlights the impacts of filler integration on the properties of PCL, indicating pathways for tailored material design aimed at sustainable solutions. [ABSTRACT FROM AUTHOR]

Low electrical conductivity and high heat dissipation are crucial for electronic packaging materials. Additionally, friction is critical for the lifespan and energy efficiency of components. To address these requirements, polymer nanocomposites based on bio‐based polyamide 1010 and ultra‐low contents of 2D nanomaterials were produced by melt‐blending. Graphene oxide, hexagonal boron nitride, and molybdenum disulfide were selected for their two‐dimensional structure and electrical insulation, providing high thermal conductivity while preserving the polymer's dielectric nature. Hybrid nanocomposites were also produced to explore potential synergistic effects. Results showed all compositions maintained the polymer's intrinsic dielectric properties. Although the friction coefficient increased slightly compared with neat polyamide, all nanocomposites remained within the low‐friction range required for low‐friction materials. Thermal conductivity improved by 5%–10% compared with unfilled polyamide, with hybrid systems performing slightly better, indicating a minor synergistic effect. Despite these enhancements being modest compared with the literature, achieving high thermal conductivity usually requires over 20 wt% of nanofiller, which is detrimental to mechanical performance. In this study, at most 0.5 wt% was used, with composites being obtained directly through melt‐blending. This highlights their potential as low‐content additives for thermal interface materials without compromising other essential properties. [ABSTRACT FROM AUTHOR]

Interfacial or separate phase location of carbonaceous nanofillers (graphene and carbon nanotubes) in polymer blends with co‐continuous phases can lead to double percolation behavior, significantly increasing rheological and electrical properties. The prediction of the morphology and the location of the nanofillers has been used as a tool to evaluate the proprieties of co‐continuous polymer blends. This work aims to highlight the superior conductivity levels achieved using a low amount of carbon‐based fillers, by the proper selection in a multiphase polymer matrix as a template for controlled dispersion and spatial distribution of the nanoparticles, offering a compromise between easy processability and enhanced performance. Here, two polymers (linear low‐density polyethylene [LLDPE] and ethylene‐co‐methylacrylate [EMA]) and their co‐continuous blend (LLDPE/EMA) were loaded with nanofillers (few‐layer graphene [FLG], few‐walled carbon nanotube [FWCNT]) via continuous melt mixing in twin‐screw extrusion, separate and simultaneously. It was observed that the addition of the nanofillers changed the co‐continuity of the blend, with the probable migration of the nanofillers from the EMA (hydrophilic) phase to the LLDPE (hydrophobic) phase. Rheological percolation occurred preferentially in blends containing FWCNT and FLG/FWCNT. Electrical conductivity was observed in all compositions, with higher electrical conductivity being noticed in hybrids. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide is a highly esteemed 2D material with interesting applications in nanoelectronics, composites, biotechnology and beyond. Its production through liquid-phase exfoliation in H2O is low-cost and eco-friendly. Herein, we present a detailed experimental and theoretical investigation seeking to explain the peculiar stability of MoS2 in H2O medium. By combining different microscopic (SEM, AFM and OM), spectrometric (Raman, UV-vis and AFM-FTIR), scattering (DLS) and ab initio simulation techniques, an edge-functionalization hypothesis for the excellent solvent properties of water for producing few-layer MoS2 has been demonstrated. [ABSTRACT FROM AUTHOR]

Surface properties are extremely important for materials applied in the biomedical areas such as poly(vinyl alcohol)—PVA. The precise control of the surface characteristics on these materials may adjust and expand its applications. Here, we present a new strategy to tune the surface properties of poly(vinyl alcohol)/graphene oxide (PVA/GO) films by manipulation of GO particles (amount and level of oxidation) and also by in situ reduction of GO. Adopting a different approach from the methods currently proposed, the reduction process of GO was carried out by exposing the PVA/GO films to hydrazine vapor to maintain the degree of particle dispersion. Raman spectroscopy, contact angle (surface energy), X‐ray diffraction, and atomic force microscopy were used to evaluate the interaction between PVA and GO particles and also to characterize graphene polymer composites properties at the surface of the films. The results indicated that there is a strong interaction between the GO particles and polar PVA groups mainly at a very specific stoichiometric ratio. Consequently, the surface properties of the PVA/GO films may be tuned by altering the concentration of the particles, their level of oxidation as well as by the exposure to hydrazine vapor. The impact of these affirmations is extremely important for improving the suitability of PVA in applications such as biomaterial, membranes, packaging, and others that need a rigorous control of surface properties. POLYM. COMPOS., 40:E312–E320, 2019. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Two-dimensional van der Waals heterostructures are attractive candidates for optoelectronic nanodevice applications. The charge transport process in these systems has been extensively investigated, however the effect of coupling between specific electronic states on the charge transfer process is not completely established yet. Here, interfacial charge transfer (CT) in the MoS2/graphene/SiO2 heterostructure is investigated from static and dynamic points of view. Static CT in the MoS2–graphene interface was elucidated by an intensity quenching, broadening and a blueshift of the photoluminescence peaks. Atomic and electronic state-specific CT dynamics on a femtosecond timescale are characterized using a core-hole clock approach and using the S1s core-hole lifetime as an internal clock. We demonstrate that the femtosecond electron transfer pathway in the MoS2/SiO2 heterostructure is mainly due to the electronic coupling between S3p–Mo4d states forming the Mo–S covalent bond in the MoS2 layer. For the MoS2/graphene/SiO2 heterostructure, we identify, with the support of density functional calculations, new pathways that arise due to the high density of empty electronic states of the graphene conduction band. The latter makes the transfer process time in the MoS2/graphene/SiO2/Si twice as fast as in the MoS2/SiO2/Si sample. Our results show that ultrafast electron delocalization pathways in van der Waals heterostructures are dependent on the electronic properties of each involved 2D material, creating opportunities to modulate their transport properties. [ABSTRACT FROM AUTHOR]

ABSTRACT The thermomechanical degradation and thermostabilization of poly(lactic acid) (PLA) have been studied using subsequent extrusion cycles under different temperature profiles. Primary and secondary antioxidants were used to avoid degradation process during extrusion. Melt flow index (MFI), size exclusion chromatography (SEC), and infrared spectroscopy (FTIR) analysis were used to evaluate the degradation and stabilization of PLA. The MFI and SEC analysis show that the main thermodegradation mechanism of PLA is governed by scission reactions. FTIR analysis confirmed the SEC results and showed that the synergetic effect between primary and secondary antioxidant is a suitable way to thermostabilize the PLA. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 40023. [ABSTRACT FROM AUTHOR]

The weathering behavior of polystyrene (PS) and PS/montmorillonite nanocomposite with and without addition of ultraviolet (UV) absorber and/or antioxidant was investigated. Samples were exposed to UV radiation in the laboratory for periods of up to approximately 12 weeks. The samples were exposed for various irradiation intervals, and their tensile and impact strength was monitored through a factorial experimental design 24. The molecular weight, yellowness, and fracture surface were also monitored. The results generated by analysis of variance (ANOVA) Table showed that UV absorber and exposure time had the most important effects positive and negative, respectively. These results could be seen for neat PS and PS/MMT nanocomposite. The presence of antioxidant alone did not have any significant effect but when mixed with UV absorber presented a small synergism. These results corroborate with molecular weight, yellowing and fracture surface of tensile and impact samples. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Blending polypropylene (PP) with biodegradable poly(3-hydroxybutyrate) (PHB) can be a nice alternative to minimize the disposal problem of PP and the intrinsic brittleness that restricts PHB applications. However, to achieve acceptable engineering properties, the blend needs to be compatibilized because of the immiscibility between PP and PHB. In this work, PP/PHB blends were prepared with different types of copolymers as possible compatibilizers: poly(propylene- g-maleic anhydride) (PP-MAH), poly (ethylene- co-methyl acrylate) [P(E-MA)], poly(ethylene- co-glycidyl methacrylate) [P(E-GMA)], and poly(ethylene- co-methyl acrylate- co-glycidyl methacrylate) [P(E-MA-GMA)]. The effect of each copolymer on the morphology and mechanical properties of the blends was investigated. The results show that the compatibilizers efficiency decreased in this order: P(E-MA-GMA) > P(E-MA) > P(E-GMA) > PP-MAH; we explained this by taking into consideration the affinity degree of the compatibilizers with the PP matrix, the compatibilizers properties, and their ability to provide physical and/or reactive compatibilization with PHB. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Molybdenum disulfide is a highly esteemed 2D material with interesting applications in nanoelectronics, composites, biotechnology and beyond. Its production through liquid-phase exfoliation in H 2 O is low-cost and eco-friendly. Herein, we present a detailed experimental and theoretical investigation seeking to explain the peculiar stability of MoS 2 in H 2 O medium. By combining different microscopic (SEM, AFM and OM), spectrometric (Raman, UV-vis and AFM-FTIR), scattering (DLS) and ab initio simulation techniques, an edge-functionalization hypothesis for the excellent solvent properties of water for producing few-layer MoS 2 has been demonstrated.

Two-dimensional van der Waals heterostructures are attractive candidates for optoelectronic nanodevice applications. The charge transport process in these systems has been extensively investigated, however the effect of coupling between specific electronic states on the charge transfer process is not completely established yet. Here, interfacial charge transfer (CT) in the MoS 2 /graphene/SiO 2 heterostructure is investigated from static and dynamic points of view. Static CT in the MoS 2 -graphene interface was elucidated by an intensity quenching, broadening and a blueshift of the photoluminescence peaks. Atomic and electronic state-specific CT dynamics on a femtosecond timescale are characterized using a core-hole clock approach and using the S1s core-hole lifetime as an internal clock. We demonstrate that the femtosecond electron transfer pathway in the MoS 2 /SiO 2 heterostructure is mainly due to the electronic coupling between S3p-Mo4d states forming the Mo-S covalent bond in the MoS 2 layer. For the MoS 2 /graphene/SiO 2 heterostructure, we identify, with the support of density functional calculations, new pathways that arise due to the high density of empty electronic states of the graphene conduction band. The latter makes the transfer process time in the MoS 2 /graphene/SiO 2 /Si twice as fast as in the MoS 2 /SiO 2 /Si sample. Our results show that ultrafast electron delocalization pathways in van der Waals heterostructures are dependent on the electronic properties of each involved 2D material, creating opportunities to modulate their transport properties.