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The subject of this research is a relatively detailed investigation of the rheological, morphological and electrical properties of nanocomposites based on polyolefin elastomer (POE), cyclic olefin copolymer (COC) and multi‐walled carbon nanotubes (MWCNTs). To formulate a mixture of two polymers (COC and POE), the melt mixing method was used and their morphology was studied by SEM technique and it was found that the morphology is of co‐continuous type. When the weight percentage ratio of COC was between 40 and 60, the desired morphology (co‐continuous) appeared. Interfacial tension calculations and TEM images proved that the nanotube particles were stabilized both within the phase of POE as well as at the interface of the two polymer phases. The rheological behavior was analyzed for composite samples containing 0–3 wt % MWCNT. The electrical and rheological percolation thresholds appeared at 1 and a 0.5 percent by weight of nanotube particles, respectively, which may be better to consider as related to the phenomenon of dual percolation. The highest conductivity was obtained for the nanocomposite containing 3% MWCNT. The results of mechanical tests also showed a strong upward trend of properties due to the addition of nanotube. Highlights: The effect of COC content on the morphology of POE/COC blend was investigated.The Morphology for the POE/COC blend at low COC content was droplet‐matrix type.MWCNT has a greater tendency to be in the POE phase than COC.Rheological behavior strongly depended on the amount of nanotube particles.The highest conductivity was obtained for the sample containing 3% MWCNT. [ABSTRACT FROM AUTHOR]

Porous poly caprolactone (PCL)/graphene oxide (GO) scaffold was fabricated using both particulate and foaming agents to yield better control over pore size. Then, the surface of the PCL/GO scaffold was modified by the aminolysis method for further treatment. Needle-like zinc oxide (ZnO) was synthesized and its antibacterial activity was verified by the disk diffusion method. Next, ZnO immobilized onto the aminolyzed PCL/GO scaffold. The mechanical test demonstrated a pronounced increment of young's modulus for the PCL scaffold. It is expected that such an engineered scaffold has a high potential to be used in tissue engineering with minimal irritation due to infections during implantation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Acoustic emission (AE) is a non-destructive method capable of detecting various fracture micromechanisms in composite materials. Discrimination of AE signals associated with various fracture modes is of interest when utilizing this technique. Thus, this paper investigates the identification of AE signal processing wavelet packet transform (WPT) failure mechanisms in wood-bioplastic nanocomposites. To this end, nanocomposites with different compositions were prepared and tested according to the ASTM D638 standard. AE signals were collected during the experiment, and analyzed by various methods. The fast Fourier transform method was used to analyze the fracture of polymers and wood and determine the frequency range of fracture. Additionally, a time-frequency analysis of the AE signal generated by the WPT was performed. The energy distribution criterion was employed to determine the main components of the various damage micromechanisms. The results reveal distinct types and percentages of failure micromechanisms in various composites. This method examined the effect of nanoparticles on the matrix's tensile strength. The scanning electron microscopy method was used to study the morphology of composites and mechanism of failure. The phase composition of the produced materials was examined with X-ray energy dispersive spectroscopy. The results demonstrated the proposed techniques show a good performance in computational damage discrimination. [ABSTRACT FROM AUTHOR]

An ethoxylated polyethylene wax (E‐OPEW) was synthesized by PEGylation reaction between methoxy polyethylene glycol and oxidized PE wax. Clay nanoparticles were modified with different ratios of E‐OPEW and then compounded with PP by the melt mixing process. E‐OPEW and PP showed excellent compatibility, but at high percentages of wax (15%), incompatibility occurred between the two phases. In addition, the presence of modified clays in the PP matrix decreased the crystallinity percentage, though it did not change the melting temperature significantly. The results showed that functionalized wax is able to penetrate between clay platelets and increase the distance between them and improve their dispersion in the polymer matrix. Furthermore, it was observed that the distance between clay platelets increased by increasing E‐OPEW content. In addition, this result led to a significant improvement in the barrier properties of clay platelets and the thermal stability of the modified nanocomposite compared to other cases. Despite the improved dispersion of nanoparticles, the mechanical strength of nanocomposites decreased at a high percentage of E‐OPEW. [ABSTRACT FROM AUTHOR]

In this research, polyolefin elastomers (POE)/starch blends were prepared using an internal mixer with 0 to 55 wt% starch content, and MAH was added into POE/starch blend to prepare a composite that improves its biodegradation, while tuning the viscoelastic behavior and morphology. The effect of the composition and the compatibilizer addition on properties, such as morphology, rheology, and the creep behavior, was investigated. The observations of microstructures through thescanning electron microscope (SEM) showed that in the incompatibilized blends, the interfacial adhesion of the phases was very weak. In contrast, in compatibilized samples, the broken surface of starch was observed confirming the enhanced interfacial tension. Additionally, the increase in the starch content led to the rise in the relaxation times. The creep test results revealed that with the increment of starch content, the creep of the blends increased. The compatibilizer improved the creep recovery of the blends. Moreover, by addition of the compatibilizer, the values of the creep parameters including η, E1, E2, and τR obtained from the standard linear solid model (SLS), was higher than those for the incompatibilized blends. The addition of POE‐MA compatibilizer can improve the properties of POE/starch blends, while keeping their biocompatibility. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48877. [ABSTRACT FROM AUTHOR]

The objective of this article was preparation of curable silane‐grafted poly(ethylene‐1‐butene) nanocomposite. The poly(ethylene‐1‐butene) was a polyolefin elastomer with random high comonomer content. Two preparation methods were investigated. The method of preparing nanocomposites significantly affected the mechanical properties of the resulted nanocomposites. So that, with the same formulation and different preparation methods, silane grafting with the first was 94% (PVDS3), while with the second was 33% (PS3VD). It was shown that the tensile strength of the cured nanocomposite prepared with the method 1 (PVDS3) increased four times higher than the pure resin. The effects of different factors such as the amount of silane and also the amount of silicon carbide on the physical, mechanical, and thermal properties of the cured and uncured nanocomposites were investigated. The rate of curing was depended on the silicon carbide concentration and 5 phr (part per hundred resin), and nano‐SiC was a concentration where the tensile properties were optimum. Thermal stability and the impermeability of the cured samples improved in the presence of nano‐silicon carbide. J. VINYL ADDIT. TECHNOL., 26:244–252, 2020. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the effects of carbon nanotube (CNT) content, surface modification, and silane cross‐linking on mechanical and electrical properties of linear low‐density polyethylene/multiwall CNT nanocomposites. CNTs were functionalized by vinyltriethoxysilane to incorporate the ─O─C2H5 functional groups and were melt‐blended with polyethylene. Silane‐grafted polyethylene was then moisture cross‐linked. Silanization of CNT was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and EDX analysis. Hot‐set test results showed that silane cross‐linking of polyethylene and incorporation of modified CNTs into polyethylene led to an increase in cross‐linking density and the number of entanglements resulting in a decrease in elongation. It was found that the addition of pristine multiwall carbon nanotubes (MWCNTs) and functionalized MWCNTs does not affect silane cross‐linking density. Silane modification resulted in a stronger adhesion of the silane cross‐linked LLDPE to silanized MWCNTs according to scanning electron microscopy micrographs. Additionally, the electrical tests revealed that the silane modification of CNTs results in an improvement in electrical properties of nanocomposites, while silane cross‐linking will not have an effect on electrical properties. Rheological properties of MWCNT/LLDPE nanocomposites have been studied thoroughly and have been discussed in this study. Moreover, according to TGA test results, modification of the MWCNTs led to a better dispersion of them in the LLDPE matrix and consequently resulted in an improvement in thermal properties of the nanocomposites. Crystallinity and melting properties of the nanocomposites have been evaluated in detail using DSC analysis. J. VINYL ADDIT. TECHNOL., 26:113–126, 2020. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

PA‐6/PVB blends and related nanocomposites with organoclay were prepared via melt‐processing and structure‐property relationships were comprehensively investigated. The SEM observations showed that blend composition and organoclay content play significant roles in the development of morphology. The differential scanning calorimetry results revealed occurrence of fractionated crystallization in the blends due to development of co‐continuous morphology. In contrast, the degree of fractionated crystallization decreased in the nanocomposites owing to role of the nanoclay as heterogeneous nucleating agent. It was found that there is an interesting relationship between morphology development and dynamic mechanical properties of the blends. Furthermore, the effects of the morphology development and nanoclay on the viscoelastic behavior of the nanocomposites were synergistic and/or counteracting depending on the Cloisite 30B content. The PA‐6/PVB blends with co‐continuous morphology showed outstanding toughness. In addition, the PA‐6/PVB50 blend with low nanoclay concentration exhibited high impact strength, which was originated from low interparticle distance between PVB domains in the matrix. POLYM. COMPOS., 40:E242–E254, 2019. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]