Preparation, characterization, and applications of poly(ethylene terephthalate) nanocomposites
01 Jan 2015-pp 167-198
TL;DR: In this paper, the present state-of-the-art technology developments in the synthesis and characterization of PET nanocomposites incorporating nanofillers such as graphene, carbon nanotubes, nanoclays, and other inorganic nanoparticles.
Abstract: Poly(ethylene terephthalate) or PET is a polymer that finds extensive application in wide-ranging areas. The incorporation of nanofillers in PET imparts significant enhancements to its properties such as mechanical strength, permeability, electrical conductivity, and thermal stability, among others. These property improvements make PET nanocomposites interesting candidates for numerous existing and emerging applications. This chapter reviews the present state-of-the-art technology developments in the synthesis and characterization of PET nanocomposites incorporating nanofillers such as graphene, carbon nanotubes, nanoclays, and other inorganic nanoparticles. The chapter also discusses various technological challenges and their implications on future trends of PET nanocomposite technology.
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13 Aug 2019
TL;DR: In this article, the authors provide an update of the main identification methods of waste electrical and electronic equipment such as spectroscopic fingerprinting, thermal study, and sample techniques (like identification code and burning test).
Abstract: Considering that the large quantity of waste electrical and electronic equipment plastics generated annually causes increasing environmental concerns for their recycling and also for preserving of raw material resources, decreasing of energy consumption, or saving the virgin materials used, the present challenge is considered to be the recovery of individual polymers from waste electrical and electronic equipment. This study aims to provide an update of the main identification methods of waste electrical and electronic equipment such as spectroscopic fingerprinting, thermal study, and sample techniques (like identification code and burning test), and the characteristic values in the case of the different analyses of the polymers commonly used in electrical and electronic equipment. Additionally, the quality of the identification is very important, as, depending on this, new materials with suitable properties can be obtained to be used in different industrial applications. The latest research in the field demonstrated that a complete characterization of individual WEEE (Waste Electric and Electronic Equipment) components is important to obtain information on the chemical and physical properties compared to the original polymers and their compounds. The future directions are heading towards reducing the costs by recycling single polymer plastic waste fractions that can replace virgin plastic at a ratio of almost 1:1.
31 citations
Cites background from "Preparation, characterization, and ..."
...These properties make PET an interesting candidate for numerous existing applications, such as packaging applications and central processing units [48,49]....
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TL;DR: The state-of-the-art of nan ofiber technology-based CB-derived HSC expansion strategies using nanofiber scaffolds is reviewed.
20 citations
TL;DR: In this paper, gold nanoparticles (AuNPs) were immobilized on the surface of an electrospun nanofibrous membrane to obtain a new hybrid material.
Abstract: This study reports the preparation of a flexible nanofibrous probe for the rapid colorimetric detection of dopamine. To this aim, gold nanoparticles (AuNPs) were immobilized on the surface of electrospun nanofibrous membrane to obtain a new hybrid material. This hybrid structure would benefit from the properties of both nanofibers and AuNP, being (a) the porosity and high surface area of nanofibers, and (b) the unique optical properties of AuNP. The electrospun poly(ethylene terephthalate) (PET) nanofibrous membrane was alkaline treated in NaOH aqueous solution, followed by immersion in the AuNP solution. The morphology of AuNP-PET membranes was characterized using a field emission scanning electron microscopy. The AuNP-PET probes showed quick, visible color change (from red to dark blue) in the presence of dopamine at the physiological pH values. The visual detection limit was 0.5 μM. The color difference based on the formula of the L*a*b* color space was used to quantify the concentration of dopamine. The color difference increased almost linearly in the 0.5–500 µM concentration range. The presence of electrostatically adsorbed AuNP on the surface of nanofibers, along with the flexibility of the nanofibrous membrane, was responsible for fast, sensitive, and on-site detection of dopamine.
18 citations
Journal Article•
TL;DR: The reported method opens a gateway to periodically patterning polymers and different functional groups on individual CNTs in an ordered and controlled manner, an attractive research field that is yet to be explored.
Abstract: We report herein a unique means to periodically pattern polymeric materials on individual carbon nanotubes (CNTs) using a controlled polymer crystallization method. One-dimensional (1D) CNTs were periodically decorated with polymer lamellar crystals, resulting in nano-hybrid shish-kebab (NHSK) structures. The periodicity of the polymer lamellae varies from 20 to 150 nm. The kebabs are approximately 5-10 nm thick (along CNT direction) with a lateral size of approximately 20 nm to micrometers, which can be readily controlled by varying crystallization conditions. Both polyethylene and Nylon 66 were successfully decorated on single-walled carbon nanotubes (SWNTs), multiwalled carbon nanotubes (MWNTs), as well as vapor grown carbon nanofibers (CNFs). The formation mechanism was attributed to \"size-dependent soft epitaxy\". Because NHSK formation conditions depend on CNT structures, it further provides a unique opportunity for CNT separation. The reported method opens a gateway to periodically patterning polymers and different functional groups on individual CNTs in an ordered and controlled manner, an attractive research field that is yet to be explored.
16 citations
TL;DR: In this article, branching polyesters based on polyethylene terephthalate were synthesized by incorporating isophthalic acid (IPA) and trimellitic anhydride (TMA).
Abstract: Branched polyesters based on the polyethylene terephthalate were synthesized by incorporating isophthalic acid (IPA) and trimellitic anhydride (TMA). TMA has the branching agent role. During the esterification step, only terephthalic acid, IPA, and ethylene glycol were reacted and TMA was added at the beginning of the polycondensation step. Reaction progress was studied using water production and mixing torque increase during esterification and polycondensation steps, respectively. Polycondensation time increases with IPA and decreases with TMA. Fourier transform infrared spectroscopy spectrum shows the production of polyester. Randomness and sequence length were studied using 13CNMR. Results reveal that randomness increases with TMA. Crystallinity and morphology of samples were studied using differential scanning microscopy (DSC). DSC thermograms show that samples turn to an amorphous structure by adding IPA and TMA with decreasing glass transition temperature, Tg. X-ray diffraction spectra approve changing nature similar to DSC results. Dynamic light scattering results present that with an increase in TMA, some size-increasing particles were detected. The rheological behavior of samples was studied using RMS. By adding TMA, the elastic behavior of samples changes to viscous behaviors.
3 citations
References
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NEC1
TL;DR: Iijima et al. as mentioned in this paper reported the preparation of a new type of finite carbon structure consisting of needle-like tubes, which were produced using an arc-discharge evaporation method similar to that used for fullerene synthesis.
Abstract: THE synthesis of molecular carbon structures in the form of C60 and other fullerenes1 has stimulated intense interest in the structures accessible to graphitic carbon sheets. Here I report the preparation of a new type of finite carbon structure consisting of needle-like tubes. Produced using an arc-discharge evaporation method similar to that used for fullerene synthesis, the needles grow at the negative end of the electrode used for the arc discharge. Electron microscopy reveals that each needle comprises coaxial tubes of graphitic sheets, ranging in number from 2 up to about 50. On each tube the carbon-atom hexagons are arranged in a helical fashion about the needle axis. The helical pitch varies from needle to needle and from tube to tube within a single needle. It appears that this helical structure may aid the growth process. The formation of these needles, ranging from a few to a few tens of nanometres in diameter, suggests that engineering of carbon structures should be possible on scales considerably greater than those relevant to the fullerenes. On 7 November 1991, Sumio Iijima announced in Nature the preparation of nanometre-size, needle-like tubes of carbon — now familiar as 'nanotubes'. Used in microelectronic circuitry and microscopy, and as a tool to test quantum mechanics and model biological systems, nanotubes seem to have unlimited potential.
39,086 citations
[...]
TL;DR: Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena can now be mimicked and tested in table-top experiments.
Abstract: Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.
35,293 citations
TL;DR: The bottom-up chemical approach of tuning the graphene sheet properties provides a path to a broad new class of graphene-based materials and their use in a variety of applications.
Abstract: The remarkable mechanical properties of carbon nanotubes arise from the exceptional strength and stiffness of the atomically thin carbon sheets (graphene) from which they are formed. In contrast, bulk graphite, a polycrystalline material, has low fracture strength and tends to suffer failure either by delamination of graphene sheets or at grain boundaries between the crystals. Now Stankovich et al. have produced an inexpensive polymer-matrix composite by separating graphene sheets from graphite and chemically tuning them. The material contains dispersed graphene sheets and offers access to a broad range of useful thermal, electrical and mechanical properties. Individual sheets of graphene can be readily incorporated into a polymer matrix, giving rise to composite materials having potentially useful electronic properties. Graphene sheets—one-atom-thick two-dimensional layers of sp2-bonded carbon—are predicted to have a range of unusual properties. Their thermal conductivity and mechanical stiffness may rival the remarkable in-plane values for graphite (∼3,000 W m-1 K-1 and 1,060 GPa, respectively); their fracture strength should be comparable to that of carbon nanotubes for similar types of defects1,2,3; and recent studies have shown that individual graphene sheets have extraordinary electronic transport properties4,5,6,7,8. One possible route to harnessing these properties for applications would be to incorporate graphene sheets in a composite material. The manufacturing of such composites requires not only that graphene sheets be produced on a sufficient scale but that they also be incorporated, and homogeneously distributed, into various matrices. Graphite, inexpensive and available in large quantity, unfortunately does not readily exfoliate to yield individual graphene sheets. Here we present a general approach for the preparation of graphene-polymer composites via complete exfoliation of graphite9 and molecular-level dispersion of individual, chemically modified graphene sheets within polymer hosts. A polystyrene–graphene composite formed by this route exhibits a percolation threshold10 of ∼0.1 volume per cent for room-temperature electrical conductivity, the lowest reported value for any carbon-based composite except for those involving carbon nanotubes11; at only 1 volume per cent, this composite has a conductivity of ∼0.1 S m-1, sufficient for many electrical applications12. Our bottom-up chemical approach of tuning the graphene sheet properties provides a path to a broad new class of graphene-based materials and their use in a variety of applications.
11,866 citations
NEC1
TL;DR: In this article, the authors reported the synthesis of abundant single-shell tubes with diameters of about one nanometre, whereas the multi-shell nanotubes are formed on the carbon cathode.
Abstract: CARBON nanotubes1 are expected to have a wide variety of interesting properties. Capillarity in open tubes has already been demonstrated2–5, while predictions regarding their electronic structure6–8 and mechanical strength9 remain to be tested. To examine the properties of these structures, one needs tubes with well defined morphologies, length, thickness and a number of concentric shells; but the normal carbon-arc synthesis10,11 yields a range of tube types. In particular, most calculations have been concerned with single-shell tubes, whereas the carbon-arc synthesis produces almost entirely multi-shell tubes. Here we report the synthesis of abundant single-shell tubes with diameters of about one nanometre. Whereas the multi-shell nanotubes are formed on the carbon cathode, these single-shell tubes grow in the gas phase. Electron diffraction from a single tube allows us to confirm the helical arrangement of carbon hexagons deduced previously for multi-shell tubes1.
8,018 citations
TL;DR: In this article, a detailed analysis of the thermal expansion mechanism of graphite oxide to produce functionalized graphene sheets is provided, where it is shown that the decomposition rate of the epoxy and hydroxyl sites exceeds the diffusion rate of evolved gases, yielding pressures that exceed the van der Waals forces holding the graphene sheets together.
Abstract: A detailed analysis of the thermal expansion mechanism of graphite oxide to produce functionalized graphene sheets is provided. Exfoliation takes place when the decomposition rate of the epoxy and hydroxyl sites of graphite oxide exceeds the diffusion rate of the evolved gases, thus yielding pressures that exceed the van der Waals forces holding the graphene sheets together. A comparison of the Arrhenius dependence of the reaction rate against the calculated diffusion coefficient based on Knudsen diffusion suggests a critical temperature of 550 °C which must be exceeded for exfoliation to occur. As a result of their wrinkled nature, the functionalized and defective graphene sheets do not collapse back to graphite oxide but are highly agglomerated. After dispersion by ultrasonication in appropriate solvents, statistical analysis by atomic force microscopy shows that 80% of the observed flakes are single sheets.
3,340 citations