Influence of multiwall carbon nanotubes on morphology and electrical conductivity of PP/ABS blends

P, George SC, Kalarikkal N, Thomas S. Enhanced mechanical and thermal performance of multiwalled carbon nanotubes-filled polypropylene/natural rubber thermoplastic elastomers

This paper reveals the effect of the concentration-dependent migration of MWCNTs among blend components on the static, dynamic, mechanical and thermal properties of MWCNT-filled PP/NR blends.

Poly(Acrylonitrile-Butadiene-Styrene) as a Special β-Nucleating Agent on the Toughness of Isotactic Polypropylene

The influence of poly(acrylonitrile–butadiene–styrene) (ABS) as a special β-nucleating agent on the impact and tensile properties of isotactic polypropylene (iPP) were investigated by dynamic rheological measurements, wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and mechanical properties tests. It is found that the β nucleation efficiency of ABS is closely related to its concentration, dispersibility, and molding method for the iPP/ABS blends. The content of β-crystal (K_β) rises with the incorporation of ABS and shows a maximum with the introduction of 1% ABS for compression-molded blends and 2% ABS for injection-molded blends, respectively, which is followed by a decrease in K_β. The addition of a small amount of ABS has a significant reinforcing and toughening effect on iPP. Compared with the compression-molded samples, the ABS dispersed phase in injection-molded samples has a smaller particle size and a larger specific surface area, which are favorable for stress transmission and higher β nucleation efficiency, and therefore, better tensile and impact properties can be expected.

Influence of Organo-Sepiolite on the Morphological, Mechanical, and Rheological Properties of PP/ABS Blends

To improve the poor impact toughness of polypropylene (PP), organo-sepiolite (O-Sep) filled 80/20 (w/w) polypropylene/poly(acrylonitrile-butadiene-styrene) (PP/ABS) nanocomposites were fabricated. The contents of O-Sep were correlated with the morphological, mechanical, and rheological behavior of PP/ABS/O-Sep blends. Scanning electron microscopy (SEM) was applied to study the morphology and thermogravimetric analysis (TGA) was applied to study the thermal stability. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were applied to study the crystallinity. The obtained results show that O-Sep enhanced the dispersion of ABS in the PP matrix and increased the crystallinity of blends. The rheological results show that O-Sep could increase the viscosity, storage modulus, and loss modulus of blends. Moreover, the mechanical behavior shows that O-Sep (at proper content) simultaneously increased the tensile modulus, flexural modulus, and impact strength of PP/ABS/O-Sep blends.

Electrical and Thermal Conductivity of Polylactic Acid (PLA)-Based Biocomposites by Incorporation of Nano-Graphite Fabricated with Fused Deposition Modeling

The aim of the study was to improve the electrical and thermal conductivity of the polylactic acid/wood flour/thermoplastic polyurethane composites by Fused Deposition Modeling (FDM). The results showed that, when the addition amount of nano-graphite reached 25 pbw, the volume resistivity of the composites decreased to 10⁸ Ω·m, which was a significant reduction, indicating that the conductive network was already formed. It also had good thermal conductivity, mechanical properties, and thermal stability. The adding of the redox graphene (rGO) combined with graphite into the composites, compared to the tannic acid-functionalized graphite or the multi-walled carbon nanotubes, can be an effective method to improve the performance of the biocomposites, because the resistivity reduced by one order magnitude and the thermal conductivity increased by 25.71%. Models printed by FDM illustrated that the composite filaments have a certain flexibility and can be printed onto paper or flexible baseplates.

Degradation and Stability of Polymeric High-Voltage Insulators and Prediction of Their Service Life through Environmental and Accelerated Aging Processes

Polymeric composite insulators consisting of core fiber reinforced polymer insulators covered with polydimethylsiloxane (PDMS) housing are now replacing conventional ceramic insulators especially for high-outdoor power transmission lines due to some specific advantages. Unlike ceramics, polymers have relatively shorter life. Outdoor insulators experience different electrical, mechanical, chemical, and thermal stresses during service. The long-term service performance of these insulators and their service life estimation is an important issue, but it is complicated and time-consuming. The objective of the present investigation is to check the rate of property deterioration during service and to find the approximate lifetime. Working insulators with different ages were collected from service, and the changes in mechanical and electrical properties and hydrophobicity of the PDMS cover against aging time were measured. The service life estimated from the change in mechanical properties and surface hydrophobicity (using MATLAB software) was compared with the service life of a new compound subjected to accelerated aging tests. Prediction of service life is helpful for replacement of aged insulators from service to avoid interruption in power transmission.

Effect of polyamide 6 on the morphology and electrical conductivity of carbon black-filled polypropylene composites

Carbon black (CB)-filled polypropylene (PP) with surface resistivity between 10⁶ and 10⁹ Ω sq^-1 is the ideal antistatic plastic material in the electronics and electric industry. However, a large amount of CB may have an adverse effect on the mechanical properties and processing performance of the material, thus an improved ternary system is developed. Blends of CB-filled PP and polyamide 6 (PA6) have been prepared by melt blending in order to obtain electrically conductive polymer composites with a low electrical percolation threshold based on the concept of double percolation. The morphological developments of these composites were studied by scanning electron microscopy. The results showed that CB particles were selectively dispersed in PA6 phases due to the good interaction and interfacial adhesion between CB and PA6. At the same CB loadings, the surface resistivity of PP/PA6/CB composite was smaller than that of PP/CB composite system, which indicated the better conductivity in the former composite. The increasing amount of PA6 in the composites changed the morphology from a typical sea-island morphology to a co-continuous morphology. What is more, with 8 wt% of CB and PP/PA6 phase ratio of 70/30 in which the PP and PA6 phases formed a co-continuous structure, the electrical conductivity of the composite peaked at 2.01 × 10⁵ Ω sq^-1.

SiC-fixed organophilic montmorillonite hybrids for poly(phenylene sulfide) composites with enhanced oxidation resistance

SiC-fixed organophilic montmorillonite hybrids exhibited improved dispersion and excellent antioxidant ability in a poly(phenylene sulfide) matrix.

Effect of carbon nanotubes on morphology evolution of polypropylene/polystyrene blends: understanding molecular interactions and carbon nanotube migration mechanisms

MWCNT migration among domains in conjunction with viscosity and elastic effects are important factors governing the morphological changes in the PP:PS blend nanocomposites.

Synthesis of MnO2 nanoparticles and their effective utilization as UV protectors for outdoor high voltage polymeric insulators used in power transmission lines

The mechanism of the UV protection of polymers by MnO₂ where UV radiation is absorbed by MnO₂ particles present in the PDMS/EVA–MnO₂ composite used in high voltage outdoor insulators for power transmission lines.

Largely improved fracture toughness of an immiscible poly(l-lactide)/ethylene-co-vinyl acetate blend achieved by adding carbon nanotubes

Through the bridging effect of CNTs, the fracture toughness of the immiscible PLLA/EVA blend was greatly improved.

Development of a high performance high voltage insulator for power transmission lines from blends of polydimethylsiloxane/ethylene vinyl acetate containing nanosilica

The blend ratio of polydimethylsiloxane (PDMS) and ethylene vinyl acetate (EVA), and nanosilica loading were optimized for open atmosphere high voltage insulator application. Environmental effects were studied by different aging characteristics.

Role of multiwalled carbon nanotubes (MWCNTs) on rheological, thermal and electrical properties of PC/ABS blend

Investigation of MWCNTs localization and its impact on rheological, electrical, and thermal properties of PC/ABS(75/25)/MWCNTs blend nanocomposites.

Peculiar morphological transitions induced by nanoparticles in polymeric blends: retarded relaxation or altered interfacial tension?

Nanoparticles of different shapes can induce peculiar morphologies in binary polymer blends depending on their position.

Influence of noncovalent modification on dispersion state of multiwalled carbon nanotubes in melt-mixed immiscible polymer blends

Multiwalled carbon nanotubes (MWNTs) were melt-mixed with polyamide6 (PA6) and acrylonitrile butadiene styrene copolymer (ABS) to obtain electrically conducting composites. MWNTs were noncovalently modified with sodium salt of 6-aminocaproic acid (MWNTs-m1) and 3-pyrenealdehyde (MWNTs-m2) to 'deagglomerate' MWNTs. Raman spectroscopic analysis indicated a G-band shift from ∼1581.9 cm(-1) for pristine MWNTs to ∼1590.2 cm(-1) for MWNTs-m1 and ∼1588.8 cm(-1) for MWNTs-m2, indicating the interaction between MWNTs and the respective modifier molecules. Blends showed 'co-continuous' morphology on the addition of MWNTs. TEM observations showed that a higher population of pristine MWNTs exhibited a 'nanoagglomerated' state in PA6 and ABS phases in the case of a 40/60 PA6/ABS blend, unlike a 60/40 blend, which depicted a higher population of 'individualized' MWNTs. Further, the corresponding blends with MWNTs-m1 and MWNTs-m2 showed 'nanoagglomerated' and 'individualized' MWNTs. Blends with pristine MWNTs showed an increase in DC electrical conductivity with an increase in PA6 concentration in the blend. Moreover, the corresponding blends with MWNTs-m1 and MWNTs-m2 exhibited an increased DC electrical conductivity value as compared to the corresponding blend with pristine MWNTs. Ratio of the intensity (H1/H2) of the crystallization peak at lower temperature (H1) to the intensity of the crystallization peak at higher temperature (H2) depicted lower values for blends with pristine MWNTs as compared to the corresponding blends with MWNTs-m1 and MWNTs-m2. TGA studies indicated the formation of a thicker 'interphase' involving MWNTs and the interacting polymer chains.

Super toughened immiscible polycarbonate/poly(l-lactide) blend achieved by simultaneous addition of compatibilizer and carbon nanotubes

By improving interfacial interaction and forming CNT network structure, the fracture resistance of immiscible PC/PLLA blend is significantly enhanced.

Design of electrical conductive composites: tuning the morphology to improve the electrical properties of graphene filled immiscible polymer blends

Polystyrene (PS) and poly(methyl methacrylate) (PMMA) blends filled with octadecylamine-functionalized graphene (GE-ODA) have been fabricated to obtain conductive composites with a lower electrical percolation threshold according to the concept of double percolation. The dependence of the electrical properties of the composites on the morphology is examined by changing the proportion of PS and PMMA. Our results reveal that the electrical conductivity of the composites can be optimal when PS and PMMA phases form a cocontinuous structure and GE-ODA nanosheets are selectively located and percolated in the PS phase. For the PS/PMMA blend (50w/50w), the composites exhibit an extremely low electrical percolation threshold (0.5 wt %) because of the formation of a perfect double percolated structure. Moreover, the rheological properties of the composites are also measured to gain a fundamental understanding of the relationship between microstructure and electrical properties.