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![Reaction mechanism of sulfuric acid with low density polyethylene , introducing sulfuric groups and carbon-to-carbon double bonds [86].](profile/Hyemin-Lee-3/publication/281687108/figure/fig16/AS:428482086871045@1479169498539/Reaction-mechanism-of-sulfuric-acid-with-low-density-polyethylene-introducing-sulfuric.png)
Reaction mechanism of sulfuric acid with low density polyethylene , introducing sulfuric groups and carbon-to-carbon double bonds [86].
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In recent decades, there has been an increasing interest in the use of carbon fiber reinforced plastic (CFRP) in aerospace, renewable energy and other industries, due to its low weight and relatively good mechanical properties compared with traditional metals. However, due to the high cost of petroleum-based precursors and their associated processi...
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... In terms of radiation sources, the molecular weight of LDPE appears to be sensitive to the irradiation source, as statistically significant differences were ascertained between the effects of E-beam and gamma radiation (Table 8). Kim et al. found that the exhaustion of cross-linkable sites occurs in ion-beam irradiated samples of LDPE that led to the subsequent predominance of scission [48]. It is quite possible that a similar phenomenon occurs here in our E-beam, X-ray, and gamma irradiated specimens. ...
... All peaks in that region are primarily attributed to C -H bending. The breakage of these C-H bonds may produce significant numbers of free radicals that form cross-links between adjacent molecular chains [48,58]. This phenomenon is further corroborated by the significant increase of the molecular weight of irradiated POE in all the irradiation methods. ...
... The DMA results of CIIR showed an increase of M c for all radiation technologies, i.e., a decrease in the cross-linking density, which correspondingly led to decreases in modulus and tensile strength of CIIR. FTIR peak changes also indicate chain scission through cleavage of quaternary carbon bonds [48]. ...
... Some well documented methods, such as peroxide crosslinking, silane crosslinking, and irradiative methods without sulfonation, yield crosslinking densities too low for carbonization [136], whereas others, such as halogenation, ammoxidation, and sulfurization have shown potential. Fig. 9. Example of a continuous fiber sulfonation reactor system for sulfonating tows of polyethylene fibers for carbon fiber production [135]. ...
Carbon fiber composites are prohibitively expensive for a wide array of applications that would greatly benefit from their superior specific strength and specific stiffness. Replacing the market-dominant carbon fiber precursor material, polyacrylonitrile, with a low-cost alternative would significantly reduce the cost of carbon fiber production. Commodity polymers may provide such an alternative thanks to their abundance and ease of production into fibers. This review presents state-of-the-art carbon fiber production from polyacrylonitrile, an overview of melt-spinnable alternative precursors broadly, and an in-depth review of the latest advances in the synthesis of carbon fibers from low-cost, commodity thermoplastics such as polyethylene, polyamide, polystyrene, polyester, and poly(vinyl chloride).
... Several studies have examined polyethylene-based carbon bers and various attempts to improve the tensile strength of polyethylene-based carbon bers have been made [19][20][21][22][23][24][25][26][27][28]. J. Kim and J. Lee examined polyethylene-derived carbon bers using LLDPE. ...
Carbon fibers were prepared using polyethylene fibers. The draw ratio of the polyethylene fibers and the sulfonation mechanism were investigated under hydrostatic pressures of 1 and 5 bar. The influence of the melt flow index of polyethylene on the sulfonation reaction was studied. Carbon fibers were prepared through the sulfonation of linear low-density polyethylene (LLDPE) fibers possessing side chains with a high melt flow index. The polyethylene fibers, which exhibited thermoplastic properties and plastic behavior, were cross-linked through the sulfonation process. Their thermal properties and mechanical properties changed to thermoset properties and elastic behavior. Although sulfonation was performed under a hydrostatic pressure of 5 bar, it was difficult to convert the highly oriented polyethylene fibers because of their high crystallinity, but partially oriented polyethylene fibers could be converted to carbon fibers. Therefore, sulfonation was performed using partially oriented LLDPE fibers with a melt flow index of 20 at 130°C for 2.5 hours under a hydrostatic pressure of 5 bar. The resulting fibers were carbonized under the following conditions: 1000°C, 5°C/min, and five minutes. Carbon fibers with a tensile strength of 2.03 GPa, a tensile modulus of 143.63 GPa, and an elongation at break of 1.42% were prepared.
... Fibres from high molecular weight PE with high values for of tensile strength and elastic modulus are readily obtainable [89]. Textile grade polyethylene has a simple chemical composition, and is attractive as a precursor for carbon fibre production as it could decrease manufacturing cost by as much as 50% compared to PAN [18,[90][91][92][93]. ...
... Peroxides have advantages compared to radiation-based crosslinking. For instance, radiation cross-linking induces the crosslinking process only on the surface of a polymer, whereas peroxide-based crosslinking can induce the crosslinking process both on the surface and inside the bulk of the polyethylene sample [91]. ...
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... For these reasons, EMI shielding materials having a low density, the ability to weaken EMI, and ease of manufacture are very important [5,6]. Recently, carbon materials have been recognized as an appropriate alternative for EMI shielding materials compared to ordinary ferrite and magnetic metals, since carbon materials provide good performance such as high strength, good electrical properties, and light weight [7,8]. Among carbon materials, carbon fibers (CFs) are suitable EMI shielding material that can absorb electromagnetic waves and withstand loads [9]. ...
In this study, an electroplating method was used to obtain good electromagnetic interference shielding efficiency (EMI-SE) of Ni-Co/carbon fibers-reinforced composites. The carbon fibers (CFs) were plated with different current density in a plating solution to observe the effects of grain size and composition rate of the alloy coating on the EMI-SE of the composites. The structural properties and morphologies of CFs were observed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). An energy dispersive spectroscopy (EDS) with an attached SEM was used for elemental analysis. The EMI-SE of the composite was measured according to ASTM D4935 and increased in proportion to the current density because of the role of Ni-Co content.
... This shows that the oxygen functional groups and surface free energy values can determine the resulting adhesion strengths of the carbon fiber/polarized polypropylene matrix in this system. Practically, the well-known ring-opening crosslinking reaction between amino-silane coupling agents (APS) and polypropylene-co-maleic anhydride can dramatically enhance the mechanical interfacial strength [29][30][31][32][33][34] of a composite. However, we used partially polarized polypropylene (Ma 0.2 -PP 99.8 ) as a matrix. ...
Thermoplastic composites are used in a variety of applications such as mass transit, automotive parts, and military structures [1-6]. Their appeal compared to conventional materials such as aluminum, steel, and thermoset composites for these applications lies in their high specific strength, corrosion resistance, superior impact resistance, high toughness, and ease of recycling [1-7].
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A patterned carbon film was produced from Linear Low-Density Polyethylene (LLDPE) by the implementation of a novel method named Chemical Masking Perforation (CMP). The following paper describes this procedure, starting with the sulfonation of the precursor polymer LLDPE with Chlorosulphonic acid to stabilize the material, followed by Fourier-transform infrared spectroscopy (FTIR) evaluation to compare the atomic bonds from the stabilized film as well as from the masked sections of the film. To finalize, the cross-linked film was carbonized in an oven at 950 °C. The outcome of this process was a carbon film with a thickness similar to a carbon fiber diameter of 8 µm with controllable size and distribution.
