Preparation and properties of polyamide 6 nanocomposites covalently linked with amide functional graphene oxide

2016 ◽  
Vol 31 (2) ◽  
pp. 162-180 ◽  
Author(s):  
Aidan O’Neill ◽  
David Bishop ◽  
Brendan Dalton ◽  
Edward Archer ◽  
Alistair McIlhagger ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
In Situ Polymerization ◽  
Single Layer ◽  
Polyamide 6 ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Covalently Linked ◽  
Thermal Analysis Techniques ◽  
Functional Graphene Oxide

Chemically engineered polyamide 6 (PA6)/graphene oxide (GO) nanocomposites were produced via the functionalization of GO with an amide (CONH2) functional group, in order to produce amide-GO with improved interfacial bonding and dispersion in the host polymer matrix. In situ polymerization of ε-caprolactam was carried out in the presence of amide-GO to create PA6/amide-GO nanocomposites. The nanomaterial (pre- and post-polymerization) and the composites were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and tensile testing. The single-layer nature of GO was attested by TEM. FTIR, XPS, XRD and thermal analysis techniques confirmed the successful amide modification of GO. The expected attachment of PA6 to the surface of GO is demonstrated, along with the reduction of GO during polymerization. Some reduction of GO during the chemical functionalization process was also observed. The thermal stability of the nanocomposites was confirmed, while promotion of α-phase crystallite formation and a molecular weight change of attached PA6 are observed. A linear improvement in stiffness and yield strength was observed as functionalized GO content increased from 0.1 wt% to 0.75 wt%. A levelling off of mechanical properties ensued once the GO content reached 1 wt%, and a decrease was seen at 2 wt%.

In Situ Fabrication of Nanoscale Graphene Oxide/Polyaniline Composite and its Electrochemical Properties

2010 ◽  
Vol 148-149 ◽  
pp. 1547-1550 ◽  
Author(s):  
Hua Lan Wang ◽  
Qing Li Hao ◽  
Xi Feng Xia ◽  
Zhi Jia Wang ◽  
Jiao Tian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
In Situ Polymerization ◽  
Ammonium Persulfate ◽  
Polymerization Process ◽  
Electrochemical Test ◽  
X Ray ◽  
Transmission Electron

A graphene oxide/polyaniline composite was synthesized by an in situ polymerization process. This product was simply prepared in an ethylene glycol medium, using ammonium persulfate as oxidant in ice bath. The composite was characterized by field emission scanning electron microscopy, transmission electron microscopy, X-Ray photoelectron spectroscopy, Raman spectroscopy and electrochemical test. The composite material showed a good electrochemical performance.

scholarly journals Fabrication of silane-grafted graphene oxide and its effect on the structural, thermal, mechanical, and hysteretic behavior of polyurethane

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Joo Hyung Lee ◽  
Seong Hun Kim
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Testing Machine ◽  
Hysteretic Behavior ◽  
Hexamethylene Diisocyanate ◽  
Scanning Calorimetry ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Ft Ir

Abstract Incorporation of nanofillers into polyurethane (PU) is a promising technique for enhancing its thermal and mechanical properties. Silane grafting has been used as a surface treatment for the functionalization of graphene oxide (GO) with numerous reactive sites dispersed on its basal plane and edge. In this study, amine-grafted GO was prepared using silanization of GO with (3-aminopropyl)triethoxysilane. The functionalized graphene oxide (fGO) was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy. Next, it was introduced in PU fabricated using polycaprolactone diol, castor oil, and hexamethylene diisocyanate. The fGO–PU nanocomposites were in turn characterized by FT-IR, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and a universal testing machine. The results obtained from these analyses showed changes in structural thermal properties, as well as improved thermal stability and mechanical properties because of the strong interfacial adhesion between the fGO and the PU matrix.

scholarly journals Porphyrin–Nanodiamond Hybrid Materials—Active, Stable and Reusable Cyclohexene Oxidation Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1402
Author(s):  
Lucas D. Dias ◽  
Fábio M. S. Rodrigues ◽  
Mário J. F. Calvete ◽  
Sónia A. C. Carabineiro ◽  
Marisa D. Scherer ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Allylic Oxidation ◽  
Reusable Catalyst ◽  
Turnover Number ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Amine Functionalized ◽  
Major Loss ◽  
Covalently Linked ◽  
Catalytic Cycles

The quest for active, yet “green” non-toxic catalysts is a continuous challenge. In this work, covalently linked hybrid porphyrin–nanodiamonds were prepared via ipso nitro substitution reaction and characterized by X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, infrared spectroscopy (IR) and thermogravimetry-differential scanning calorimetry (TG-DSC). The amine-functionalized nanodiamonds (ND@NH2) and 2-nitro-5,10,15,20-tetra(4-trifluoromethylphenyl)porphyrin covalently linked to nanodiamonds (ND@βNH-TPPpCF3) were tested using Allium cepa as a plant model, and showed neither phytotoxicity nor cytotoxicity. The hybrid nanodiamond–copper(II)–porphyrin material ND@βNH-TPPpCF3-Cu(II) was also evaluated as a reusable catalyst in cyclohexene allylic oxidation, and displayed a remarkable turnover number (TON) value of ≈265,000, using O2 as green oxidant, in the total absence of sacrificial additives, which is the highest activity ever reported for said allylic oxidation. Additionally, ND@βNH-TPPpCF3-Cu(II) could be easily separated from the reaction mixture by centrifugation, and reused in three consecutive catalytic cycles without major loss of activity.

On polyamide 6-montmorillonite nanocomposites obtained by in-situ polymerization

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Orietta Monticelli ◽  
Zenfira Musina ◽  
Francesca Ghigliotti ◽  
Saverio Russo ◽  
Valerio Causin
Keyword(s):  
In Situ Polymerization ◽  
Active Role ◽  
Polyamide 6 ◽  
Layered Silicates ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Close Relationship ◽  
Restricted Mobility

AbstractNanocomposites based on polyamide 6 (PA6) and montmorillonite-type (MMT) commercial clays, either unmodified or organically modified, were prepared by in-situ polymerization of ε-caprolactam (CL). The above materials were characterized in detail by a number of experimental techniques, including transmission electron microscopy (TEM), wide angle X-ray diffraction (WAXD), infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The formation of nanostructured systems was checked not only for the commonly used ω-aminoacid-modified clay, but also for other types of organoclays. In general, a correlation was found between nanoscopic swelling of the clay in molten CL, measured by X-ray diffraction, and level of clay dispersion in PA6. Specifically, with the most swellable clays, completely exfoliated nanocomposites were obtained. However, also layered silicates modified by compatibilizers having carboxy groups, because of the active role of latter in CL polymerization, formed delaminated nanocomposites despite their low degree of swelling in CL monomer. Both molecular mass and crystallinity of the polyamide matrix were found to be strongly influenced by the presence of specific layered silicates. In particular, some characterization techniques (WAXD, FTIR) have evidenced a close relationship between the MMT used and PA6 crystal structure. Namely, PA6 γ-form is promoted by clay with compatibilizer bearing the carboxy group, which is able to induce the polymer to be tethered on the silicate layers, thus provoking conditions of restricted mobility to occur.

Structure and Phase Transformations in Thermoelastic Ni(1−x)TiCux) Thin Films Prepared by D.C. Magnetron Sputtering.

1990 ◽  
Vol 187 ◽  
Author(s):  
L. Chang ◽  
C. Hu-Simpsono ◽  
D. S. Grummon ◽  
W. Pratt ◽  
R. loloee
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Phase Transformations ◽  
Photoelectron Spectroscopy ◽  
Single Layer ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sputtered Films ◽  
Transmission Electron ◽  
Shape Memory Effects

AbstractThe intermetallic compound NiTi and its copper containing variants, Ni(1−x)TiCu(x), are capableof stress induced displacive tansformations which give rise to superelasticity and shape-memory effects. Thin films of these alloys, which may find use as sensors, microactuators, or as protective surface microalloys, are of increasing interest. In this study, thin films in the Ni(1−x)TiCUx) system, ranging in thickness from 250 nm to 5 μm, were prepared with a triode-type D.C. magnetron sputtering apparatus using a ternary alloy target. Both homogeneous films and periodic multilayer structures (with interspersed Ti-rich layers) were fabricated. of particular interest were shifts in composition with respect to the target, and the structural and phase transformation characteristics of the sputtered films. These phenomena were examined using transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray microanalysis. Transformation temperatures and enthalpies were determined by differential scanning calorimetry and confirmed by 4-point D.C. resistivity measurements. The as-sputtered films were amorphousbut crystallized during annealing at 923K. Electron diffraction and XPS data suggested the presence of oxygen. Single layer film compositions were shifted to slightly lower Ti fractions which depressed the onset of the transformation sequence by ˜35K and degraded phase stability during annealing. It was possible, however, to produce periodic multilayer films which showed evidence of thermoelastic phase transformations during DSC, resistivity, and in-situ TEM experiments. These films were stable with respect to vacuum annealing at 923 K for 6 h.

scholarly journals Investigation on the Effect of Hyperbranched Polyester Grafted Graphene Oxide on the Crystallization Behaviors of β-Nucleated Isotactic Polypropylene

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1988 ◽  
Author(s):  
Yansong Yu ◽  
Xi Jiang ◽  
Yiwei Fang ◽  
Jinyao Chen ◽  
Jian Kang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Isotactic Polypropylene ◽  
Photoelectron Spectroscopy ◽  
Crystallization Process ◽  
Hyperbranched Polyester ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystallization Behaviors ◽  
Transmission Electron

In this article, hyperbranched polyester grafted graphene oxide (GO) was successfully prepared. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) were performed for its characterizations. On the other hand, differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) were also performed to study its influences on non-isothermal crystallization behaviors of β-nucleated isotactic polypropylene (β-iPP). The grafting ratios of hyperbranched polyester with different supermolecular structures were calculated to be 19.8–24.0 wt %, which increase with the degree of branching. The results showed that the grafting of hyperbranched polyester was advantageous in increasing the crystallization peak temperature Tp and decreasing the crystallization activation energy ΔE of β-iPP/GO composites, which contributed to the iPP’s crystallization process. Moreover, under all cooling rates (2, 5, 10, 20, 40 °C/min), crystallinities of β-iPP/GO were greatly improved after being grafted with hyperbranched polyester, because of the increase of the relative contents of α-phase αc and the average α-crystal sizes.

Preparation and characterization of conducting nylon 6 fibers

2009 ◽  
Vol 24 (8) ◽  
pp. 2728-2735 ◽  
Author(s):  
A. Saritha Chandran ◽  
Sunil K. Narayanankutty
Keyword(s):  
Photoelectron Spectroscopy ◽  
In Situ Polymerization ◽  
Fiber Surface ◽  
Nylon 6 ◽  
Etching Time ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

Conducting nylon 6 fibers were prepared by in situ polymerization of aniline on to the fiber surface, after providing a chemical etching treatment to the fibers using chromic acid. The properties of the etched and polyaniline (PANI) coated fibers were evaluated using scanning electron microscopy, x-ray photoelectron spectroscopy, infrared spectroscopy, x-ray diffraction, thermogravimetry, and differential scanning calorimetry. Though the etching process caused a marginal decline in the mechanical properties of the fiber, it provided a reasonably rough surface for PANI adhesion and enhanced the conductivity of the fiber. The conductivity increased from 4.22 × 10−2 to 3.72 × 10−1 S/cm at an etching time of 4 h.

scholarly journals X-ray Photoelectron Spectroscopy Analysis of Chitosan–Graphene Oxide-Based Composite Thin Films for Potential Optical Sensing Applications

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 478
Author(s):  
Wan Mohd Ebtisyam Mustaqim Mohd Daniyal ◽  
Yap Wing Fen ◽  
Silvan Saleviter ◽  
Narong Chanlek ◽  
Hideki Nakajima ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Functional Group ◽  
Optical Sensing ◽  
Composite Thin Films ◽  
Cobalt Ions ◽  
X Ray ◽  
Sensing Applications

In this study, X-ray photoelectron spectroscopy (XPS) was used to study chitosan–graphene oxide (chitosan–GO) incorporated with 4-(2-pyridylazo)resorcinol (PAR) and cadmium sulfide quantum dot (CdS QD) composite thin films for the potential optical sensing of cobalt ions (Co2+). From the XPS results, it was confirmed that carbon, oxygen, and nitrogen elements existed on the PAR–chitosan–GO thin film, while for CdS QD–chitosan–GO, the existence of carbon, oxygen, cadmium, nitrogen, and sulfur were confirmed. Further deconvolution of each element using the Gaussian–Lorentzian curve fitting program revealed the sub-peak component of each element and hence the corresponding functional group was identified. Next, investigation using surface plasmon resonance (SPR) optical sensor proved that both chitosan–GO-based thin films were able to detect Co2+ as low as 0.01 ppm for both composite thin films, while the PAR had the higher binding affinity. The interaction of the Co2+ with the thin films was characterized again using XPS to confirm the functional group involved during the reaction. The XPS results proved that primary amino in the PAR–chitosan–GO thin film contributed more important role for the reaction with Co2+, as in agreement with the SPR results.

scholarly journals pH-controlled synthesis of sustainable lauric acid/SiO2 phase change material for scalable thermal energy storage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shafiq Ishak ◽  
Soumen Mandal ◽  
Han-Seung Lee ◽  
Jitendra Kumar Singh
Keyword(s):  
Electron Microscopy ◽  
Phase Change ◽  
Lauric Acid ◽  
Photoelectron Spectroscopy ◽  
Phase Change Materials ◽  
Precursor Solution ◽  
Thermal Reliability ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heating And Cooling

AbstractLauric acid (LA) has been recommended as economic, eco-friendly, and commercially viable materials to be used as phase change materials (PCMs). Nevertheless, there is lack of optimized parameters to produce microencapsulated PCMs with good performance. In this study, different amounts of LA have been chosen as core materials while tetraethyl orthosilicate (TEOS) as the precursor solution to form silicon dioxide (SiO2) shell. The pH of precursor solution was kept at 2.5 for all composition of microencapsulated LA. The synthesized microencapsulated LA/SiO2 has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The SEM and TEM confirm the microencapsulation of LA with SiO2. Thermogravimetric analysis (TGA) revealed better thermal stability of microencapsulated LA/SiO2 compared to pure LA. PCM with 50% LA i.e. LAPC-6 exhibited the highest encapsulation efficiency (96.50%) and encapsulation ratio (96.15%) through Differential scanning calorimetry (DSC) as well as good thermal reliability even after 30th cycle of heating and cooling process.

X-Ray Photoelectron Spectroscopy Study on Reduction of Graphene Oxide with Hydrazine Hydrate

2011 ◽  
Vol 287-290 ◽  
pp. 539-543 ◽  
Author(s):  
Wen Shi Ma ◽  
Jun Wen Zhou ◽  
Xiao Dan Lin
Keyword(s):  
Graphene Oxide ◽  
Hydrazine Hydrate ◽  
Photoelectron Spectroscopy ◽  
Reduction Rate ◽  
Reduction Reaction ◽  
Chemical Compositions ◽  
Total Oxygen ◽  
Graphene Oxides ◽  
X Ray ◽  
Oxygen Groups

Graphene oxide was prepared through Hummers' method，then different reduced graphenes were prepared via reduction of graphene oxide with hydrazine hydrate for 1h、12h and 24h. X-ray photoelectron spectroscopy (XPS) was used for the characterization of graphene oxide and the reduced graphenes. The variation of the contents of carbon in carbon and oxygen functional groups and chemical compositions of graphene oxides were investigated through analysis the content of different carbon atoms in different reduced graphenes. The results showed that the reduction reaction was very fast in the first 1 h, the content of total oxygen bonded carbon atoms decreased from 83.6% to 22.1%, and then after the reduction rate became very slow. After 12h, the content of total oxygen bonded carbon atom is 19.56%, only 2.54% lower than that of 1h’s. At the same time, C-N was introduced in the graphene oxides; this increased the stereo-hindrance for hydrazine hydrate attacking the C-Oxygen groups, thus reduced the reduction rate. After reduction for 24h, there still exists 16.4% oxygen bonded carbon atoms and the total conversion ratio of graphene approaches 70%.

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