scholarly journals Effect of Graphene Oxide as a Reinforcement in a Bio-Epoxy Composite

2021 ◽  
Vol 5 (3) ◽  
pp. 91
Author(s):  
Anthony Loeffen ◽  
Duncan E. Cree ◽  
Mina Sabzevari ◽  
Lee D. Wilson
Keyword(s):  
Graphene Oxide ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Scanning Calorimetry ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Materials Research ◽  
Improved Performance ◽  
Modified Hummers Method ◽  
Properties Of Composites

Graphene oxide (GO) has gained interest within the materials research community. The presence of functional groups on GO offers exceptional bonding capabilities and improved performance in lightweight polymer composites. A literature review on the tensile and flexural mechanical properties of synthetic epoxy/GO composites was conducted that showed differences from one study to another, which may be attributed to the oxidation level of the prepared GO. Herein, GO was synthesized from oxidation of graphite flakes using the modified Hummers method, while bio-epoxy/GO composites (0.1, 0.2, 0.3 and 0.6 wt.% GO) were prepared using a solution mixing route. The GO was characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscope (TEM) analysis. The thermal properties of composites were assessed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). FTIR results confirmed oxidation of graphite was successful. SEM showed differences in fractured surfaces, which implies that GO modified the bio-epoxy polymer to some extent. Addition of 0.3 wt.% GO filler was determined to be an optimum amount as it enhanced the tensile strength, tensile modulus, flexural strength and flexural modulus by 23, 35, 17 and 31%, respectively, compared to pure bio-epoxy. Improvements in strength were achieved with considerably lower loadings than traditional fillers. Compared to the bio-epoxy, the 0.6 wt.% GO composite had the highest thermal stability and a slightly higher (positive) glass transition temperature (Tg) was increased by 3.5 °C, relative to the pristine bio-epoxy (0 wt.% GO).

scholarly journals High-Tribological-Performance Polymer Nanocomposites: An Approach Based on the Superlubricity State of the Graphene Oxide Agglomerates

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2237
Author(s):  
Eder H. C. Ferreira ◽  
Angela Aparecida Vieira ◽  
Lúcia Vieira ◽  
Guilhermino J. M. Fechine
Keyword(s):  
Graphene Oxide ◽  
High Viscosity ◽  
Tribological Performance ◽  
Multilayer Graphene ◽  
High Concentration ◽  
Scanning Calorimetry ◽  
Mechanical Reinforcement ◽  
Transmission Electron ◽  
Twin Screw ◽  
Mechanical Tensile

Here, nanocomposites of high-molecular-weight polyethylene (HMWPE) and HMWPE-UHMWPE (80/20 wt.%) containing a low amount of multilayer graphene oxide (mGO) (≤0.1 wt.%) were produced via twin-screw extrusion to produce materials with a higher tribological performance than UHMWPE. Due to the high viscosity of both polymers, the nanocomposites presented a significant concentration of agglomerates. However, the mechanical (tensile) and tribological (volumetric loss) performances of the nanocomposites were superior to those of UHMWPE. The morphology of the nanocomposites was investigated using differential scanning calorimetry (DSC), microtomography, and transmission electron microscopy (TEM). The explanation for these results is based on the superlubricity phenomenon of mGO agglomerates. It was also shown that the well-exfoliated mGO also contained in the nanocomposite was of fundamental importance as a mechanical reinforcement for the polymer. Even with a high concentration of agglomerates, the nanocomposites displayed tribological properties superior to UHMWPE’s (wear resistance up to 27% higher and friction coefficient up to 57% lower). Therefore, this manuscript brings a new exception to the rule, showing that agglomerates can act in a beneficial way to the mechanical properties of polymers, as long as the superlubricity phenomenon is present in the agglomerates contained in the polymer.

The Synthesis and Characterization of the Graphene Oxide Covalent Modified Phenolic Resin Nanocomposites

2011 ◽  
Vol 327 ◽  
pp. 115-119 ◽  
Author(s):  
Duo Wang ◽  
Jie Gao ◽  
Wei Fang Xu ◽  
Feng Bao ◽  
Rui Ma ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Phenolic Resin ◽  
Synthesis And Characterization ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hummers Method ◽  
Modified Hummers Method ◽  
Thermal Stability Of

Graphene oxide (GO) was made by a modified Hummers method. Graphene oxide modified phenolic resin nanocomposites (GO/PF) were prepared by Steglich esterification, catalyzed by dicyclohexyl carbodiimide and 4-dimethylaminopyridine. The composites were characterized by Fourier transform infrared spectrometry, differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. The result revealed that the graphene oxide was absolutely exfoliated and covalent linked GO/PF composite was obtained. The thermal stability of PF is remarkably improved by modification with GO.

Influence of two novel compatibilizers on the properties of LDPE/organoclay nanocomposites

2014 ◽  
Vol 34 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Haydar U. Zaman ◽  
Dalour Hossen Beg
Keyword(s):  
Molecular Weight ◽  
Tensile Modulus ◽  
Low Molecular Weight ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Nucleation Effect ◽  
Transmission Electron ◽  
Linear Viscoelastic ◽  
Silicate Clay

Abstract In the present investigation, low density polyethylene (LDPE)/organoclay nanocomposites with various clay contents (1–7 wt%) were prepared via a melt mixing technique, using two different compatibilizers with various contents; low molecular weight trimethoxysilyl-modified polybutadiene (Organosilane) and low molecular weight oxidized polyethylene (OxPE). The effects of incorporation of compatibilizers and clay contents on the mechanical and thermal properties of the nanocomposites were investigated. The dispersibility of silicate clay in the nanocomposites was investigated by transmission electron microscopy (TEM). It was found that organosilane yielded better clay dispersion and a more exfoliated structure compared with the OxPE. Rheological behavior of the samples was examined by a dynamic oscillatory rheometer in the linear viscoelastic region. The organosilane compatibilized system conferred higher tensile strength, yield strength and tensile modulus than those of an uncompatibilized system, and even higher than those of the OxPE compatibilized case. The crystallization behaviors of uncompatibilized and compatibilized nanocomposites were investigated using differential scanning calorimetry (DSC). DSC results indicated that the addition of compatibilizers increased the crystallization temperature (Tc) as a result of heterogeneous nucleation effect of clay on LDPE.

HIGH-IMPACT PP NANOCOMPOSITES: INFLUENCE OF CLAY CONTENT ON MECHANICAL AND THERMAL PROPERTIES

2013 ◽  
Vol 12 (06) ◽  
pp. 1350039
Author(s):  
L. G. FURLAN ◽  
RICARDO V. B. OLIVEIRA ◽  
ANDRÉIA C. E. MELLO ◽  
SUSANA A. LIBERMAN ◽  
MAURO A. S. OVIEDO ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Impact Strength ◽  
Flexural Modulus ◽  
Clay Content ◽  
Mechanical Analysis ◽  
High Impact ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Izod Impact

The preparation of high-impact polypropylene nanocomposites with different organo-montmorillonite (O-MMT) contents by means of meltprocessing was investigated. The nanocomposite properties were evaluated by transmission electron microscopy (TEM), flexural modulus, izod impact strength, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was noticed that the PP/O-MMT nanocomposites properties were affected by clay content. Exceptional improvements in impact strength were obtained (maximum of 185%) by the use of low O-MMT content. The results showed that higher enhancement on mechanical/thermal properties was obtained by 3 wt.% of O-MMT instead of higher quantities.

scholarly journals Preparation and characterization of baicalein loaded phytosomes: Assessment of in vitro parameters

2020 ◽  
Vol 12 (4) ◽  
pp. 22-29
Author(s):  
KanchanV Zade ◽  
Alok Pal Jain
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Herbal Extracts ◽  
Scanning Calorimetry ◽  
Reverse Phase ◽  
Tem Analysis ◽  
Transmission Electron

Phytosome is a complex between natural active ingredient and a phospholipid. Further, phytosomes been applied to many popular herbal extracts or active molecules for augmenting oral dissolution. Therefore, in present investigation, orally administered Baicalein, atype of flavanoids, is poorly absorbed, and shows suboptimal dissolution. The phytosomes encapsulating baicalein (1:1 Mm) were prepared by reverse phase evaporation method followed by lyophilization. Transmission electron microscopy (TEM) analysis revealed that phytosomes were almost spherical in shape with particle size below 100 nm. The Powder ex-ray diffraction (PXRD) and differential scanning calorimetry (DSC) demonstrated that Baicalein loaded phytosomes were amorphous in nature. Amorphization of therapeutic moiety leads to improvement in dissolution. In conclusion, epigallocatechin loaded phytosomes exhibited promising results and warrant further in vitro andin vivo investigations under a set of stringent parameters for transforming in to a clinically viable products.

Synthesis of Graphene Oxide Nanosheets via Modified Hummers’ Method and Its Physicochemical Properties

2015 ◽  
Vol 74 (1) ◽  
Author(s):  
Mohamad Fahrul Radzi Hanifah ◽  
Juhana Jaafar ◽  
Madzlan Aziz ◽  
Ahmad Fauzi Ismail ◽  
Mukhlis A. Rahman ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Physicochemical Properties ◽  
Functional Groups ◽  
Interlayer Spacing ◽  
Graphene Oxide Nanosheets ◽  
Hummers Method ◽  
Exfoliated Graphene ◽  
Transmission Electron ◽  
Direct Methanol ◽  
Modified Hummers Method

The efficient synthesis of exfoliated graphene oxide nanosheets (GO) via modified Hummers’ method was successfully carried out. The physicochemical properties of GO were determined by Fourier transform infrared spectroscopy (FTIR), UV-visible spectrophotometry (UV-vis), x-ray diffraction analysis (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The graphite was fully oxidized by strong oxidizing agent caused the oxygen-containing functional groups such as C-O-C, C=O, and COOH were introduced into the graphite layers as analyzed by Raman and FTIR.  XRD pattern of GO showed 2θ of 12.0o with interlayer spacing ~ 7.37A which describe non uniform crystal structure with the addition of oxygen containing functional groups. UV-vis spectrum of GO exhibit maximum absorption peak at ~ 234 nm corresponding to the aromatic C=C bond with π-π* transition. The morphology of GO was observed to have flake-like shape and less transparent layers by TEM. The properties of synthesized GO suggest high potential in producing the high quality of graphene which is can be applied as the electrocatalyst support for direct methanol fuel cell application.              

scholarly journals Influence of Organo-Sepiolite on the Morphological, Mechanical, and Rheological Properties of PP/ABS Blends

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1493 ◽  
Author(s):  
Wang ◽  
Li ◽  
Xie ◽  
Wu ◽  
Huang ◽  
...  
Keyword(s):  
Loss Modulus ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Acrylonitrile Butadiene Styrene ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Poor ◽  
Poly Acrylonitrile ◽  
Butadiene Styrene

To improve the poor impact toughness of polypropylene (PP), organo-sepiolite (O-Sep) filled 80/20 (w/w) polypropylene/poly(acrylonitrile-butadiene-styrene) (PP/ABS) nanocomposites were fabricated. The contents of O-Sep were correlated with the morphological, mechanical, and rheological behavior of PP/ABS/O-Sep blends. Scanning electron microscopy (SEM) was applied to study the morphology and thermogravimetric analysis (TGA) was applied to study the thermal stability. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were applied to study the crystallinity. The obtained results show that O-Sep enhanced the dispersion of ABS in the PP matrix and increased the crystallinity of blends. The rheological results show that O-Sep could increase the viscosity, storage modulus, and loss modulus of blends. Moreover, the mechanical behavior shows that O-Sep (at proper content) simultaneously increased the tensile modulus, flexural modulus, and impact strength of PP/ABS/O-Sep blends.

scholarly journals Novel Bioactive and Antibacterial Acrylic Bone Cement Nanocomposites Modified with Graphene Oxide and Chitosan

2019 ◽  
Vol 20 (12) ◽  
pp. 2938 ◽  
Author(s):  
Mayra Eliana Valencia Zapata ◽  
José Herminsul Mina Hernandez ◽  
Carlos David Grande Tovar ◽  
Carlos Humberto Valencia Llano ◽  
José Alfredo Diaz Escobar ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Graphene Oxide ◽  
Cell Viability ◽  
Flexural Modulus ◽  
Hydrolytic Degradation ◽  
Biological Properties ◽  
Flexural Behavior ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Surgical Interventions

Acrylic bone cements (ABCs) have played a key role in orthopedic surgery mainly in arthroplasties, but their use is increasingly extending to other applications, such as remodeling of cancerous bones, cranioplasties, and vertebroplasties. However, these materials present some limitations related to their inert behavior and the risk of infection after implantation, which leads to a lack of attachment and makes necessary new surgical interventions. In this research, the physicochemical, thermal, mechanical, and biological properties of ABCs modified with chitosan (CS) and graphene oxide (GO) were studied. Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H-NMR) scanning electron microscopy (SEM), Raman mapping, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), compression resistance, mechanical dynamic analysis (DMA), hydrolytic degradation, cell viability, alkaline phosphatase (ALP) activity with human osteoblasts (HOb), and antibacterial activity against Gram-negative bacteria Escherichia coli were used to characterize the ABCs. The results revealed good dispersion of GO nanosheets in the ABCs. GO provided an increase in antibacterial activity, roughness, and flexural behavior, while CS generated porosity, increased the rate of degradation, and decreased compression properties. All ABCs were not cytotoxic and support good cell viability of HOb. The novel formulation of ABCs containing GO and CS simultaneously, increased the thermal stability, flexural modulus, antibacterial behavior, and osteogenic activity, which gives it a high potential for its uses in orthopedic applications.

scholarly journals Significant Enhancement of Mechanical and Thermal Properties of Thermoplastic Polyester Elastomer by Polymer Blending and Nanoinclusion

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Manwar Hussain ◽  
Young Hui Ko ◽  
Yong Ho Choa
Keyword(s):  
Electron Microscopy ◽  
Thermal Properties ◽  
Flexural Modulus ◽  
Tensile Elongation ◽  
Thermoplastic Elastomer ◽  
Melt Processing ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Polymer Blending ◽  
Tem Analysis

Thermoplastic elastomer composites and nanocomposites were fabricated via melt processing technique by blending thermoplastic elastomer (TPEE) with poly(butylene terephthalate) (PBT) thermoplastic and also by adding small amount of organo modified nanoclay and/or polytetrafluoroethylene (PTFE). We study the effect of polymer blending on the mechanical and thermal properties of TPEE blends with and without nanoparticle additions. Significant improvement was observed by blending only TPEE and virgin PBT polymers. With a small amount (0.5 wt.%) of nanoclay or PTFE particles added to the TPEE composite, there was further improvement in both the mechanical and thermal properties. To study mechanical properties, flexural strength (FS), flexural modulus (FM), tensile strength (TS), and tensile elongation (TE) were all investigated. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to analyze the thermal properties, including the heat distortion temperature (HDT), of the composites. Scanning electron microscopy (SEM) was used to observe the polymer fracture surface morphology. The dispersion of the clay and PTFE nanoparticles was confirmed by transmission electron microscopy (TEM) analysis. This material is proposed for use as a baffle plate in the automotive industry, where both high HDT and high modulus are essential.

scholarly journals Performance of Straw/Linear Low Density Polyethylene Composite Prepared with Film-Roll Hot Pressing

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 860
Author(s):  
Lei Zhang ◽  
Huicheng Xu ◽  
Weihong Wang
Keyword(s):  
Hot Pressing ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Thermoplastic Composites ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Scanning Calorimetry ◽  
Polyethylene Composite ◽  
Extrusion Method

Thermoplastic composites are usually prepared with the extrusion method, and straw reinforcement material must be processed to fiber or powder. In this study, film-roll hot pressing was developed to reinforce linear low density polyethylene (LLDPE) with long continuous straw stems. The long straw stems were wrapped with LLDPE film and then hot pressed and cooled to prepare straw/LLDPE composite. Extruded straw fiber/LLDPE composite was prepared as a control. The mechanical properties of these LLDPE-based composites were evaluated. The hot pressed straw/LLDPE composite provided higher tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength than the traditional extruded straw/LLDPE composite, by 335%, 107%, 68%, 57%, and 181%, respectively, reaching 35.1 MPa, 2.65 GPa, 3.8 MPa, 2.15 GPa, and 25.1 KJ/m2. The density of the hot pressed straw/LLDPE composite (0.83 g/cm3) was lower than that of the extruded straw/LLDPE composite (1.31 g/cm3), and the former had a higher ratio of strength-to-weight. Scanning electron microscopy indicated that the orientation of the straws in the composite was better with the new method. Differential scanning calorimetry tests revealed that in hot pressed straw/LLDPE composite, straw fibers have a greater resistance to the melting of LLDPE than extruded composite. Rotary rheometer tests showed that the storage modulus of the hot pressed straw/LLDPE was less affected by frequency than that of the extruded composite, and the better elastic characteristics were pronounced at 150 °C. The hot pressed straw/LLDPE composite absorbed more water than the extruded composite and showed a potential ability to regulate the surrounding relative humidity. Our results showed that straw from renewable sources can be used to produce composites with good performance.

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