Polymer Blend Nanocomposites Research Articles

Ionic liquid based NCPBE membranes for electrochemical capacitor applications: Structural, thermal and electrical transport properties

The current study focuses on the preparation and characterisation of imidazolium ionic liquid based plasticized nano-composite polymer blend electrolytes (NCPBEs). Semi-crystalline nature of the synthesized samples was observed using XRD analysis. ATR-FTIR results demonstrate the interaction among the carbonyl (CO) and hydroxyl (O–H) groups of polymers with ionic liquid (IL) and salt, NaI. Furthermore, thermo-gravimetric analysis (TGA) indicates multi-step decomposition process. Ion transport mechanism has been analysed using temperature dependent conductivity analysis, ac conductivity analysis and dielectric properties study. The sample containing 25 wt% IL i.e. NCPBE-25 has the ionic conductivity ∼9.30 × 10−4 Scm−1 with the optimum vale of charge carrier density, mobility, and ion diffusivity at 30oC. Ions are principal charge carriers in the present electrolytes. The sample NCPBE-25 has the electro-chemical stability window −3.6 to 1.5 V at room temperature. The fabricated electro-chemical capacitor has the specific capacitance, energy density and power density 363.27 Fg-1, 50.45 Whkg−1 and 18.16 kW/kg, respectively at the scan rate 5 mV/s.

Structural and optical properties of polymer blend nanocomposites based on PVP/PVA incorporated AgNO3

In this study, polymer nanocomposite based on polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and silver nitrate (AgNO3) has been prepared through chemical reduction rate and casting method for varying concentrations of AgNO3. The PVP/PVA blend consisted of 0.6 wt% PVP and 0.4 wt% PVA. Following that, polymer nanocomposites were prepared by incorporating different concentrations of AgNO3 (0, 10, 20, 30, 40, and 50 wt%) into the polymer blend. The effects of different concentrations of AgNO3 on the structural and optical properties of the PVP/PVA blend were investigated using x-ray diffraction (XRD) and UV–vis absorption spectroscopy. The XRD analysis demonstrated that increasing the concentration of AgNO3 results in a decrease in the degree of crystallinity from 53.73 in the PVP/PVA blend to 15.77 in the PVP/PVA nanocomposite containing 50 wt% AgNO3. UV–vis absorbance spectra were examined to determine optical properties such as the absorption coefficient, absorption edge, optical band gap, and tails of localized states. The results revealed that the increase in AgNO3 concentrations caused a reduction in the absorption edge and optical band gap, alongside an increase in Urbach energy.

Synthesis of biopolymer blends nanocomposites embedded with mono-(Ag, Fe) and bi-(Ag-Fe) metallic nanoparticles using an eco-friendly approach for antimicrobial activities.

Plant-mediated solution casting is used to develop eco-friendly polymer blend nanocomposites from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) doped with Silver (Ag), Ferrous (Fe) monometallic and Silver-Ferrous (Ag-Fe) bimetallic nanoparticles (NPs). These nanocomposites were studied to understand their electromagnetic interface (EMI) shielding efficiency and antimicrobial activities, besides evaluating their physical and chemical properties. The Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX) characterization techniques were used to examine the interactions between the polymers, the presence of silver and ferrous particles in the composites, the crystallinity shift, the surface morphology, the shape and size of the nanoparticles and the distribution of the nanoparticles in the composites. The FTIR spectra showed the interactions among the components of the composites. According to XRD spectra, the incorporation of nanoparticles into the PVA polymer significantly reduced the crystalline character of the polymer from 0.38 to 0.24 for the composition consisting of silver and iron nanoparticles in equal proportion. The results from SEM, EDX and XRD corroborate the presence of nanoparticle forms. The thermogravimetric analysis (TGA) tests reveal that the thermal stability of bimetallic composites is greater than that of monometallic composites. The tensile properties showed that the addition of nanoparticles to the PVA/PVP polymer matrix increased its mechanical strength from 59.3MPa to 85.5MPa. We examined its efficacy against Escherichia coli, Staphylococcus aureus and Candida albicans as microorganisms. Good antibacterial and antifungal activity was observed. The bimetallic composites demonstrated greater activity than monometallic composites against these bacterial and fungal species. All bimetallic nanocomposites have shown enhanced, loss due to reflection, loss due to absorption, and the total EMI shielding efficiency at 8GHz (X-band) and 16GHz (Ku-band) frequency. All these results ratify, that these newly developed bio nanocomposites are most suitable in many applications, in EMI shielding, nanotechnology, and medical fields.

Production of supertough and semiconductive PLA-based polymer blend nanocomposites by kinetic microstructural control

Polymer nanocomposites with superior multi-functional properties can be fabricated by tuning their morphology. In this work, a supertough and semiconductive polylactide (PLA)-based polymer blend nanocomposite (PBNANO) was produced for the first time via melt blending with a core-shell rubber (CSR) and carbon nanotubes (CNT). Reference binary blends (PLA/CSR and PLA/CNT) revealed that, when added separately, 20 wt% of CSR and 0.25 wt% of CNT were the suitable quantities to achieve a supertough and a semiconductive PLA-based material, respectively. Based on the obtained results, PLA/CSR/CNT PBNANOs with 20 wt% of CSR and CNT amounts between 0.15 and 0.50 wt% were prepared in one extrusion step. Although supertoughness was achieved in all the cases, the PBNANOs were insulating due to the selective localization of the CNT in the poly(methyl methacrylate) (PMMA) shell of the CSR and the good dispersion of the CSR nanoparticles. However, a supertough and semiconductive PLA-based PBNANO was obtained by a two-step melt compounding. Using this processing sequence, a worse dispersion of the CSR was obtained, allowing contact between some CSR nanoparticles. The differences in PBNANOs morphology prepared in one or two extrusion steps were determined by TEM and corroborated by rheological measurements. In the case of the two extrusion steps PBNANO, the CNT were located in both the PLA matrix and in the shell of the CSR. This morphological change enabled the PBNANO to be conductive, as the CNT percolation was achieved in this case while still remaining supertough.

Investigation of structure and optical characteristics of irradiated PVP/CMC nanocomposite films based on ZnS/SnO2 nanofillers

AbstractPVP/CMC/50%ZnS‐50%SnO2 blends were formed by solid state reaction, sol‐gel methods and casting technique. The structure and the crystallite size of the nanofillers (ZnS and SnO2) were examined using x‐ray diffraction technique (XRD). The effect of laser irradiation energies compared to the proportions of loaded nanofillers on the films internal structure and morphology was studied using XRD. The high miscibility among blends has been confirmed through Fourier transform infrared spectroscopy (FTIR). The energy dispersive x‐ray spectroscopy (EDS) analysis proved the presence of the nanocomposite polymer blends constituent atoms. The blends surface morphology has been investigated through scanning electron microscope (SEM). The dual effect of both different laser energies and oxygen atoms content simultaneously, on the linear and nonlinear optical parameters of nanocomposite films were explored as well. Results showed that, the laser irradiation energy process has the highest enhancement on the optical properties. The optical band gap (Eg) values were reduced from 4.8 eV (in the case of unirradiated blend) to 3.5 eV (for blends irradiated with 150 mJ/cm2) for allowed direct transitions, but for allowed indirect transitions Eg decreased from 3.3 eV (for unirradiated) to 2.2 eV (for irradiated with 150 mJ/cm2).Highlights A comparative discussion upon the effect of excess oxygen atoms has been represented. A dominant effect for the laser exposure compared to both the particle size and excess oxygen atoms. The variations of the nanocomposite films structural and optical features were promising.

Nanocomposite polymer blend membrane molecularly re-engineered with 2D metal-organic framework nanosheets for efficient membrane CO2 capture

Membrane gas separation technology is an energy-efficient alternative to the traditional industrial processes for CO2 capture towards the mitigation of global warming. To overcome the inherent performance trade-off behavior of polymeric membranes, many nanoarchitectures have been incorporated for developing high-performance mixed matrix membranes. Yet, a successful nanocomposite membrane design remains challenging, especially for CO2 capture, because of polymer-filler incompatibility and interfacial defects. Herein, 2D Cu-TCPP nanosheets were synthesized and incorporated into Pebax/Poly (ethylene glycol) methyl ether acrylate (PEGMEA) blends to design MMMs with exceptional CO2/N2 separation performance. This synergistic polymer blend after crosslinking, offers a highly accommodating and robust matrix environment for the homogenous distribution of nanosheets. Cu-TCPP particles were also produced as 3D nanoflowers to probe their morphological effect on gas transport. The finely dispersed 2D nanosheets expanded the free volume of the resultant nanocomposite membranes, leading to a significantly enhanced CO2 permeability of up to 1183 Barrer which was 93% higher than the neat polymers, while they also increased the transport pathway tortuosity that contributes to a very high CO2/N2 selectivity of 57.6 at a loading of merely 0.1 wt%. Not only do such separation performances surpassed the Robeson upper bound by a large margin and outcompeted many existing advanced MMM designs, but they also remained stable after long-term operations. By carefully elucidating the gas transport tuning effect of 2D metal-organic framework nanosheets in nanocomposite membranes, this work could help broaden their applicability for other environmentally important molecular separations.

Preparation and properties of double percolated co-continuous PC/PET/MWCNT/GNP engineering polymer blend nanocomposites

This study reports on the preparation and characterization of nanocomposites based on polycarbonate (PC)/poly ethylene terephthalate (PET) blend containing low amounts of hybrid of multiwalled carbon nanotube (MWCNTs) and graphene nanoplates (GNPs) by melt mixing. To use double percolation mechanism, at first a co-continuous polymer blend was prepared and the influence of nanofiller content on morphology, electrical conductivity, rheological and mechanical properties of co-continuous PC/PET blend was investigated. Blend containing 60 wt. % PET showed co-continuous morphology as observed by scanning electron microscopy and it was found that co-continuity remained unchanged by the addition of nanofillers. The direct current (DC) electrical conductivity results showed a low electrical percolation threshold around 0.5 phr. The results obtained from differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) showed an increase in thermal stability and crystallinity of nanocomposites. By increasing nanofiller amount, the storage modulus, loss modulus, and complex viscosity of samples increased as an indication of the strong network formation between nanofillers and polymer chains. The rheological percolation threshold was also found in the range of 2.5–3.5 phr of nanofillers. The tensile measurements results showed that the addition PC to PET increases the tensile strength of PET.

Particle-size dependent stability of co-continuous polymer blends

The properties of polymer blend nanocomposites are typically associated with spatiotemporal distribution of nanoparticles within a polymer blend system. Here, we present in situ high-temperature confocal rheology studies to assess the effect of particle size on the extent of particle agglomeration, particle migration, and subsequently their influence on the coarsening dynamics of polymer blends filled with pristine silica particles. We investigate co-continuous polypropylene-poly(ethylene-co-vinyl acetate) blends filled with five different silica particles with a diameter ranging from 5 to 490 nm. While particle size does not play a role when particles are thermodynamically driven to their preferred polymer phase, a striking effect is achieved when particles are kinetically trapped at the interface. We find that the interparticle interaction largely driven by size dependent long-range repulsive forces governs their extent of agglomeration, severely affecting their ability to stabilize co-continuous morphology. Strikingly, the largest (490 nm) particles are more effective in suppressing coarsening than 5 nm particles, while 140 and 250 nm particles are found to be the most effective. We demonstrate that kinetic trapping of primary particles of either size is influenced by the interplay of interfacial folding during melt blending and Laplacian pressure exerted at the interface. These results extend our fundamental understanding of the stabilization of co-continuous morphology in polymer blends by particles.

Development of poly (linear low‐density ethylene)/poly (ethylene‐methyl co‐acrylate) blends with enhanced thermal‐stability and toughening behavior with adding of carbonaceous fillers

AbstractIn this work, polymer blend nanocomposites based on carbon fillers were produced via melt‐compounding in a twin‐screw extruder. A combination of several matrices (LLDPE, EMA, and LLDPE/EMA) and fillers (FLG, FWCNT, and FLG/FWCNT) was used. Thermal enhancement as the consequence of few‐walled carbon nanotube addition, led to significant improvements in the initial degradation temperatures of LLDPE (383.2 > 441.2°C), EMA (371.2 > 417.3°C), and LLDPE/EMA (390.55 > 430.62°C) matrixes, respectively. The evaluation of the dynamic‐mechanical behavior of the compositions showed an increase of 80% in the storage module for LLDPE‐based nanocomposites, a reduction of 30% for blend‐based nanocomposites, and a non‐change for EMA nanocomposites. Tenacity property was considerably improved, achieving a value 78% higher to the LLDPE/EMA blend, mainly due to the possible migration of the nanoparticles from EMA phase to the LLDPE phase, creating a more efficient physical network with well‐developed percolating structure, which facilitates the dissipation of energy during mechanical loading. In summary, it can be observed that the morphology control as well as the nanofillers location, proved to be extremely relevant factors to produce a polymer film with enormous gains in the thermal and mechanical properties.

Crystal and morphology development in immiscible nonpolar polymer blend nanocomposite based on low‐density polyethylene and linear low‐density polyethylene in presence of clay and compatibilizer

AbstractIn this work, polyolefin‐blend/clay nanocomposites based on low‐density polyethylene (LDPE), linear low‐density polyethylene (LLDPE), and organically modified clay (OC) were prepared by melt extrusion. Various grades of maleic anhydride (MA) grafted polyethylene (PE‐g‐MA) were used and examined as compatibilizers in these nanocomposites. Differential scanning calorimetry analysis showed that OC and compatibilizer affect the crystallization behavior of LDPE/LLDPE with different mechanisms. Thermodynamic calculations of wetting coefficient based on interfacial energy between OC, LD, and LL, Morphological characterization based on field emission scanning electron microscopy, X‐ray diffraction, small angles X‐ray scattering, and dynamic rheology measurements revealed that the compatibilizer and OC were localized at the interface of LDPE and LLDPE phases with a preferred tendency toward one phase. Results demonstrated that at a specific amount of OC, there is an optimum compatibilizer concentration to achieve nanodispersed OC and beyond that the compatibilizer causes a structural change in the polymer crystalline morphology. It was also found that the tensile property enhancement of LDPE/LLDPE/OC nanocomposites is closely related to the crystalline structure development made by incorporation of both OC and compatibilizer.

Superior electrical conductivity and mechanical properties of phase‐separated polymer blend composites by tuning the localization of nanoparticles for electromagnetic interference shielding applications

AbstractThe assimilation of highly conductive nanofillers in immiscible polymer blends has shown great potential for various applications. Recent advancements in controlling the location of nanoparticles at the interface of immiscible binary blends have enhanced mechanical and electrical performance of the composites. However, the dispersion, distribution, and localization of the nanoparticles at the interface of immiscible binary blends are considered the principal challenges to determining the mechanical and electrical performance of the composites. This has led to considerable interest in exploiting the location of nanoparticles at the interface of immiscible binary blends for electromagnetic Interference (EMI) shielding applications. This review critically inspects the possible mechanism for locating the nanofillers at the interface and their influence on the electrical conductivity and mechanical properties. Furthermore, numerous strategies, such as covalent modification of nanoparticles, optimizing processing time and sequence of mixing, are highlighted for performance improvement of binary blend nanocomposites. In addition, we reviewed the compatibility of nanoparticles with the polymer matrix at the interface correlation with dispersion and mechanical properties. Finally, some challenges in the development, modification, and location of nanoparticles at the interface of immiscible polymer blend nanocomposites for EMI shielding applications are described.

Chemical modification strategies for the control of graphene localization in PS/PMMA blend

This work concerns the nanoparticles localization control in a PMMA/PS polymer blend. In this article, a complete study was made on the poly(methylmethacrylate)/polystyrene/graphene (PMMA/PS/graphene) polymer blend nanocomposites performed by a melt-blending process at PMMA/PS equal proportion (50/50). Graphene nanoparticles were modified via different chemical modification strategies such as Hummers’ oxidation (GOxH), hydrazine reduction (GOxH-r2) and copolymer functionalization by a “grafting onto” method. The evolution of graphene nanoparticles morphology, chemical structure during the melt-blending process were investigated to explain their final localization. Considering GOxH nanoparticles, the in-situ reduction during the process was proved by Raman spectroscopy, FTIR and XRD. The stability of the copolymer grafting was also confirmed after melt-compounding by Py-GC/MS. The predicted localization by thermodynamics was compared to the real localization determined by STEM images. Functionalized graphene (GOxN-PMMA, GOxH-PMMA, GOxH-r2-PMMA, GOxH-r2-PMMA-r1) showed a transfer from PS to PMMA, whereas non-functionalized nanoparticles (G, GOxH, GOxH-r2) remain in PS. Graphene migration mechanisms and polymer blend microstructures were also investigated. Graphene nanoparticles interaction with polymer matrices and their impact on viscosity was studied by rheology to assess the final microstructure of the polymer blend nanocomposites.

Investigation of structural and conductivity properties of poly(vinyl alcohol)‐based electrospun composite polymer blend electrolyte membranes for battery applications

AbstractSolid polymer electrolyte has attracted great interest for the next generation of electrochemical devices such as batteries, but the low ionic conductivity and poor stability has retarded their commercial acceptance for energy storage devices applications. To overcome these issues, strategies to develop composite polymer electrolytes (CPEs) are drawing interest. Nanocomposite solid polymer blend electrolyte membranes based on poly (vinyl alcohol) (PVA), poly (vinyl pyrrolidone) (PVP) of various compositions that contained potassium nitrate (KNO3) as a dopant salt, and Barium Titanate (BaTiO3) as a filler were prepared with various concentrations of filler using electrospinning technique. The structural and complex formations due to interaction of various groups of the prepared composite polymer electrolyte membranes were investigated using X‐ray diffraction (XRD) and Fourier transform infra‐red (FTIR) spectral analysis. The conductivity of the PVA‐PVP‐KNO3‐BaTiO3 polymer electrolyte systems was found to vary between 3.71×10‐9 and 1.99×10‐5 S cm‐1 at 298 K with the increase in filler concentration. The maximum room temperature ionic conductivity (1.99×10‐5 S cm‐1) has been obtained for 9 wt% BaTiO3 doped polymer electrolyte system. The addition of filler also enhanced the thermal stability of the electrolyte. The temperature dependence ionic conductivity of the prepared complexed polymer electrolyte systems appears to obey Arrhenius behaviour.

Carbon Nanotube Migration in a Compatibilized Blend System, Leading to Kinetically Induced Enhancement in Electrical Conductivity and Mechanical Properties

Kinetic factors that facilitate carbon nanotube (CNT) migration in a polymer blend from a high-density polyethylene (HDPE) phase to a poly (p-phenylene ether) (PPE) phase were studied, with the objective to induce CNT migration and localization at the interface. Herein, a CNT filler was pre-localized in an HDPE polymer and then blended with PPE at different blend compositions of 20:80, 40:60, 60:40, and 80:20 of PPE/HDPE at a constant filler concentration of 1 wt%. The level of CNT migration was studied at different mixing times of 5 and 10 min. The electrical conductivity initially increased by 2-3 orders of magnitude, with an increase in the PPE content up to 40%, and then it decreased significantly by up to 12 orders of magnitude at high PPE content up to 100%. We determined that the extent of migration was related to the difference in the melt viscosity between the constituent polymers. A triblock copolymer styrene-ethylene/butylene-styrene (SEBS) was used to improve the blend miscibility, and 2 wt% copolymer was found to be the optimum concentration for the electrical properties for the two blend compositions of 20:80 and 80:20 of PPE/HDPE, at a constant filler concentration of 1 wt%. The introduction of the SEBS triblock copolymer significantly increased the conductivity almost by almost four orders of magnitude for PPE/HDPE/80:20 composites with 1 wt% CNT and 2 wt% SEBS compared to the uncompatibilized blend nanocomposite. The mechanical strength of the compatibilized blend nanocomposites was found to be higher than the unfilled compatibilized blend (i.e., without CNT), uncompatibilized blend nanocomposites, and the pristine blend, illustrating the synergistic effect of adding nanofillers and a compatibilizer. SEM and TEM microstructures were used to interpret the structure-property relationships of these polymer blend nanocomposites.

Morphological, structural, optical, broadband frequency range dielectric and electrical properties of PVDF/PMMA/BaTiO3 nanocomposites for futuristic microelectronic and optoelectronic technologies

Polymer blend nanocomposite (PBNC) films consisted of fluoropolymer poly(vinylidene fluoride) (PVDF) and plexiglass polymer poly(methyl methacrylate) (PMMA) blend host matrix (fixed composition blend of PVDF/PMMA = 80/20 wt/wt%) with barium titanate (BaTiO3) ceramic nanofiller of varying concentrations (x = 0, 2.5, 5, 10, and 15 wt%) were prepared via a state-of-the-art solution-cast method. Scanning electron microscope (SEM) images evidenced high homogeneity of these PBNC films and a huge alteration in the spherulite morphology of the PVDF with the increase in dispersed BaTiO3 concentration in the polymer blend matrix. The X-ray diffraction (XRD) patterns identified the presence of electro-active polar β- and γ-phases of the PVDF crystallites in all the composite materials which are supported by the results of Fourier transform infrared (FTIR) spectra. The differential scanning calorimeter (DSC) thermograms explained the high melting temperature of these overlapped PVDF polymorphs and the degree of crystallinity altered anomalously with the variation of nanofiller concentration. The absorbance of ultraviolet-visible (UV-Vis) radiations enhanced while the direct energy band gap of the 80PVDF/20PMMA blend matrix and also the semiconducting BaTiO3 was found to decrease with the increased concentration of nanomaterial in the host polymer matrix. The ambient temperature broadband dielectric spectra covering the frequency range from 20 Hz to 1 GHz explain that the real part of complex dielectric permittivity reduced with a huge dispersion at higher radio frequencies where the dielectric loss tangent and electric modulus spectra exhibited an intense chain segmental relaxation process. The electrical conductivity of these PBNC films increased with frequency augmented and illustrated a small variation for different concentration composites. The experimental results demonstrated that these PVDF/PMMA/BaTiO3 films could be potential candidates for frequency tunable nanodielectric, electromagnetic interference shielders, a flexible dielectric substrate, thermal insulators, and bandgap regulated materials for futuristic microelectronic, capacitive energy storage, and optoelectronic technologies.

PVC/PVP/SrTiO3 polymer blend nanocomposites as potential materials for optoelectronic applications

This paper presents, for the first time, the preparation and study of the thermal decomposition and optical properties of PVC/PVP/SrTiO3 polymer blend nanocomposites. The polymer films were characterized using X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Raman, thermogravimetric analysis (TGA), and optical spectroscopy techniques. XRD spectra indicated semicrystalline structure of the PVC/PVP polymer blend and revealed cubic crystal structure of the SrTiO3 nanoparticles. The lattice constant of SrTiO3 was found to decrease from 2.79 to 2.75 Å upon increasing the concentration of the SrTiO3 nanoparticles in the blend to 0.6 wt%. The FTIR and Raman spectra revealed the strong interaction between PVC/PVP polymer blend and SrTiO3. The TGA analysis showed a slight enhancement of the polymer blend thermal stability. Moreover, the thermal kinetic parameters, such as activation energy, entropy and Gibbs free energy, of the polymer nanocomposites were lower than those of the pure PVC/PVP blend counterpart. The addition of SrTiO3 increased the optical absorption, energy gap, and linear refractive index. Furthermore, the optical susceptibility and nonlinear refractive index were significantly improved. For all polymer blends, a fluorescence peak appeared at a wavelength of 485 nm. These outcomes qualify the PVC/PVP/SrTiO3 polymer blend nanocomposites for optoelectronic applications.

Carbon Nanotube Migration in Melt-Compounded PEO/PE Blends and Its Impact on Electrical and Rheological Properties.

In this work, the effects of MWCNT concentration and mixing time on the migration of multi-walled carbon nanotubes (MWCNTs) within polyethylene oxide (PEO)/polyethylene (PE) blends are studied. Two-step mixing used to pre-localize MWCNTs within the PE phase and subsequently to observe their migration into the thermodynamically favored PEO phase. SEM micrographs show that many MWCNTs migrated into PEO. PEO/PE 40:60 polymer blend nanocomposites with 3 vol% MWCNTs mixed for short durations exhibited exceptional electromagnetic interference shielding effectiveness (EMI SE) and electrical conductivity (14.1 dB and 22.1 S/m, respectively), with properties dropping significantly at higher mixing times, suggesting the disruption of percolated MWCNT networks within the PE phase. PE grafted with maleic anhydride (PEMA) was introduced as a compatibilizer to arrest the migration of MWCNTs by creating a barrier at the PEO/PE interface. For the compatibilized system, EMI SE and electrical conductivity measurements showed a peak in electrical properties at 5 min of mixing (15.6 dB and 68.7 S/m), higher than those found for uncompatibilized systems. These improvements suggest that compatibilization can be effective at halting MWCNT migration. Although utilizing differences in thermodynamic affinity to draw MWCNTs toward the polymer/polymer interface of polymer blend systems can be an effective way to achieve interfacial localization, an excessively low viscosity of the destination phase may play a major role in reducing the entrapment of MWCNTs at the interface.

A combined method to probe the behaviour of the filler in polymer blend nanocomposites via X-ray diffraction and thermal measurement

We have demonstrated the use of XRD and thermal measurements to diligently probe the location of nano-scaled boron carbide (B4C-type compounds) fillers. Herein, the XRD diffraction Bragg and amorphous peaks were successfully fitted from the parameters determined by a deconvolution process using the Pearson VII function, with a fitting error of less than 4%. Thermal measurement was achieved by measuring the thermal conductivity of the composite. A filler loading of 4%wt was found as a threshold. Beyond this value, a significant increase in the thermal conductivity was observed. There was no further decrease in the HDPE crystallinity above the threshold, but rather a considerable increase. Below the threshold value, the addition of fillers disturbed the HDPE crystal arrangement, leading to a reduction of both the HDPE crystallinity and the thermal conductivity. The influence on the ordered structure, intrinsic thermal conductivity and radius of gyration of the fillers, together with their interactions, elucidated the trend of the thermal conductivity.

Crystallization Kinetics and Mechanical Properties of Miscible Polymer Blend Nanocomposites: Linear versus Grafted Systems

Crystallization Kinetics and Mechanical Properties of Miscible Polymer Blend Nanocomposites: Linear versus Grafted Systems

H-BN Modification Using Several Hydroxylation and Grafting Methods and Their Incorporation into a PMMA/PA6 Polymer Blend

Hexagonal boron nitride (h-BN) has recently gained much attention due to its high thermal conductivity and low electrical conductivity. In this study, we proposed to evaluate the impact of the modification of h-BN for use in a polymethylmethacrylate/polyamide 6 (PMMA/PA6) polymer blend. Different methods to modify h-BN particles and improve their affinity with polymers were proposed. The modification was performed in two steps: (1) a hydroxylation step for which three different routes were used: calcination, acidic treatment, and ball milling using gallic acid; (2) a grafting step for which four different silane agents were used, carrying different molecular or macromolecular groups: the octadecyl group (Si-C18), propyl amine group (Si-NH2), polystyrene chain (Si-PS), and PMMA chain (Si-PMMA). The modified h-BN samples after hydroxylation and functionalization were characterized by FTIR and TGA. Py-GC/MS was also used to prove the successful graft with Si-C18 groups. Sedimentation tests and multiple light scattering were performed to assess the surface modification of h-BN. Granulometry and SEM observations were performed to evaluate the particle size distribution after hydroxylation. After the addition of Si-PMMA modified h-BN into a PMMA/PA6 co-continuous blend, the morphology of the polymer blend nanocomposites was characterized using SEM. The calculation of the wetting parameter based on the surface tension measurement using the liquid drop model showed that h-BN dispersed in the PA6 phase. Grafting PMMA chains onto hydroxylated h-BN particles combined with an adequate sequence mixing led to a successful localization of the grafted h-BN particles at the interface of the PMMA/PA6 blend.