Waste NR latex based-precursors as carbon source for CNTs eco-fabrications

In this work, the potential of utilizing a waste latex‐based precursor (i.e., natural rubber glove (NRG)) as a carbon source for carbon nanotube (CNT) fabrication via chemical vapor deposition has been demonstrated. Gas chromatography‐mass spectroscopy (GC‐MS) analysis reveals that the separation of the lightweight hydrocarbon chain from the heavier long chain differs in hydrocarbon contents in the NRG fraction (NRG‐L). Both solid NRG (NRG‐S) and NRG‐L samples contain >63% carbon, <0.6% sulfur and <0.08% nitrogen content, respectively, as per carbon‐nitrogen‐sulfur (CNS) analysis. Growth of CNTs on the samples was confirmed by Raman spectra, SEM and TEM images, whereby it was shown that NRG‐S is better than NRG‐L in terms of synthesized CNTs yield percentage with similar quality. The optimum vaporization and reaction temperatures were 350 and 800 °C, respectively, considering the balance of good yield percentage (26.7%) and quality of CNTs (ID/IG = 0.84 ± 0.08, diameter ≈ 122 nm) produced. Thus, utilization of waste NRG as a candi-date for carbon feedstock to produce value‐added CNTs products could be a significant approach for eco‐technology

Associations between knowledge on optimal control of serum phosphate, perceived social support, dietary phosphorus intake and phosphate compliance among hemodialysis patients

Introduction: Hyperphosphatemia is common among hemodialysis patients, often accompanies with unfavourable clinical outcomes. Several factors affect phosphate compliance among hemodialysis patients, with lack of such information at the local context. Thus, this cross-sectional study aimed to determine the associations of sociodemographic factors, knowledge on optimal control of serum phosphate, perceived social support from family, dietary phosphorus intake and phosphate compliance among hemodialysis patients. Methods: Structured questionnaire was used to obtain information on socioeconomic factors, knowledge, family social support and dietary phosphorus intakes of hemodialysis patients, with serum phosphate level was used as the surrogate marker for phosphate compliance. Results: A total of 76 patients (Mean age of 52 years old) were recruited. Hyperphosphatemia was prevalent with approximately 60% of the patients failed to achieve the target. Approximately 90% of the patients perceived low level of family social support. Young patients had significant higher serum phosphate compared to their older counterparts (r = -0.297, p =0.009). Serum phosphate was positively correlated with dietary intake of phosphorus, dialysis vintage (r = 0.301, p = 0.006) and comorbidity score (r = 0.325, p = 0.008) while negatively correlated with dialysis dose (r = -0.582, p = 0.002) and family social support (r = -0.263, p = 0.024). Conclusion: The promising role of dietary phosphorus intake in managing hyperphosphatemia deserves further attention. Innovative approaches are needed to promote self-adherence on serum phosphate especially the younger patients. It is imperative to promote family social support in the management of hyperphosphatemia among hemodialysis patients

Recent developments in carbon nanotubes-reinforced ceramic matrix composites: A review on dispersion and densification techniques

Ceramic matrix composites (CMCs) are well-established composites applied on commercial, laboratory, and even industrial scales, including pottery for decoration, glass–ceramics-based light-emitting diodes (LEDs), commercial cooking utensils, high-temperature laboratory instruments, industrial catalytic reactors, and engine turbine blades. Despite the extensive applications of CMCs, researchers had to deal with their brittleness, low electrical conductivity, and low thermal properties. The use of carbon nanotubes (CNTs) as reinforcement is an effective and efficient method to tailor the ceramic structure at the nanoscale, which provides considerable practicability in the fabrication of highly functional CMC materials. This article provides a comprehensive review of CNTs-reinforced CMC materials (CNTs-CMCs). We critically examined the notable challenges during the synthesis of CNTs-CMCs. Five CNT dispersion processes were elucidated with a comparative study of the established research for the homogeneity distribution in the CMCs and the enhanced properties. We also discussed the effect of densification techniques on the properties of CNTs-CMCs. Additionally, we synopsized the outstanding microstructural and functional properties of CNTs in the CNTs-CMCs, namely stimulated ceramic crystallization, high thermal conductivity, bandgap reduction, and improved mechanical toughness. We also addressed the fundamental insights for the future technological maturation and advancement of CNTs-CMCs

Effect of reaction temperature on the growth of carbon nanotubes from waste natural rubber glove

Natural rubber (NR) glove disposal is not environmentally appropriate and a range of approaches have been suggested to overcome the problem. Herein we indicate a simple method for producing high-value nanotubes from waste NR glove as a partial solution to the environmental problem. The laboratory-based waste NR glove was selected as a carbon precursor. Carbon nanotubes (CNTs) were synthesized using chemical vapor deposition (CVD) method comprising ferrocene over SiO2 substrate, which acted as a catalyst and surface for the carbon conversion process. The growth temperature was varied using 500, 600 and 700°C. The carbon precursor was analyzed using thermogravimetric analysis (TGA) to determine the optimum thermal decomposition of the waste. The CNTs collected after CVD process were analyzed using Raman spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM). Optimization studies to determine the effect of temperature showed that the highest yield of CNTs was produced under a reaction temperature of 700°C (yield % = 5.47%, Raman ID/IG ratio = 0.82). The nanomaterials formed confirmed as CNTs and amorphous carbon under TEM images of the tubular structure of the products with a diameter range of 13 – 16 nm

Study of structural and electrical behavior of silicon-carbon nanocomposites via in situ transmission electron microscopy

In this work, we have studied the structural and electrical behavior of Si-incorporated carbon nanostructures (Si-CNS) by performing current-voltage (I-V) measurements using in situ transmission electron microscopy (TEM). The I-V measurement and TEM observation of the corresponding Si-CNS structural transformation during the process were investigated in detail. Structural transformation of Si-CNS was occurred at high electric current flow (~µA), and reached its peak before electrical breakdown damaging the nanostructures. The formation of few graphene layer from initially amorphous structure were observed with embedded Si particles. The graphitic structures significantly improve the Si-CNS electrical properties depending on the nanostructure shape and Si-C composition. The current increased up to ~24.8 μA for nanofiber, and ~3 mA for nanocone, indicating the improvement of Si-C matrix crystallinity and decrement of Si composition from sublimation due to current-induced Joule heating. In situ heating technique revealed that Si particle begin to agglomerate at ~500 °C and the graphitization on the Si surface occurred at > 700 °C in a low pressure environment (~10−5 Pa). The combination of the in situ TEM study can be promising for further understanding of Si-C structural and electrical behavior towards the future development of next-generation electronic and energy applications

Tuning the optical bandgap of multi-walled carbon nanotube-modified zinc silicate glass-ceramic composites

Novel glass-ceramic composites with optical bandgap tunability were synthesised. Zinc silicate powder (ZS) was mixed with multi-walled carbon nanotubes (MWCNTs) at various mass fractions (0, 1, 2, and 3 wt %), followed by argon sintering. X-ray diffraction (XRD) analysis revealed the structural change from an amorphous ZS phase to a crystalline willemite phase (Zn2SiO4) by adding MWCNTs, and the largest crystallite size was obtained for ZS with 2.0 wt% MWCNTs. Although the agglomeration of ZS and MWCNTs was observed by field emission scanning electron microscopy (FESEM), there was no chemical interaction between ZS and MWCNTs as confirmed by Fourier transform infrared spectroscopy (FTIR). MWCNTs enhanced the crystallisation, which led to the green emission of Zn2SiO4 blue-shifting from 572 nm to 557 nm. The narrowed optical bandgap of Zn2SiO4 was attributed to the MWCNT-induced exciton localised between the valence band and conduction band of Zn2SiO4. The bandgap tuning effect of MWCNTs potentially paved new ways to mass fabricate zinc silicate-based semiconductors with desirable optical bandgap energy Eg, which significantly benefits the sensor and laser-related industry

Effect of CNT on microstructural properties of Zn2SiO4/CNT composite via dry powder processing

This work focused on the influence of carbon nanotubes(CNT)to the microstructural properties of Zn2SiO4/CNT (ZSO/CNT) composite. CNT was synthesized via alcohol catalytic chemical vapor deposition (ACCVD) using cobalt oxide as catalyst and ethanol as carbon source. Zinc silicate (ZSO)glass was prepared from quenching the melted commercial waste glass bottle with zinc oxide powder. ZSO/CNT-x composites with various CNT concentration (0, 1, 2 and 3 wt%)was prepared through introducing CNT into ZSO glass via dry processing technique followed by sintering process in Argon gas(Ar) environment and atmospheric (atm) environment, respectively. FESEM, XRD and EDS were employed to determine the surface morphology, phase composition and elemental distribution of sintered sample. Crystallite trigonal willemite (Zn2SiO4) phase was observed from argon sintered sample and the crystallite size of willemite phase in ZSO/CNT-3/Ar showed the most reduced lattice strain of 22.85% compared to ZSO/CNT-0/Ar. In contrast, semi crystalline phase exhibited in atmospheric sintered sample resulted in high lattice strain. It is concluded that dry powder processing and inert gas thermal treatment can be an effective technique in fabricating strain-reduced ceramics/ CNT composite without alternating the domain phase. Least internal strain in crystal lattice have potential on enhancing the luminescence properties of phosphor material and lattice thermal conductivity of thermoelectric material