scholarly journals Barrier Properties of GnP–PA-Extruded Films

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 669
Author(s):  
Regine Boldt ◽  
Andreas Leuteritz ◽  
Daniela Schob ◽  
Matthias Ziegenhorn ◽  
Udo Wagenknecht
Keyword(s):  
Filler Content ◽  
Barrier Properties ◽  
Permeation Rate ◽  
Graphene Nanoplatelets ◽  
Laboratory Scale ◽  
Morphological Properties ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Extruded Films ◽  
Different Temperatures

It is generally known that significant improvements in the properties of nanocomposites can be achieved with graphene types currently commercially available. However, so far this is only possible on a laboratory scale. Thus, the aim of this study was to transfer results from laboratory scale experiments to industrial processes. Therefore, nanocomposites based on polyamide (PA) and graphene nanoplatelets (GnP) were prepared in order to produce membranes with improved gas barrier properties, which are characterized by reduced permeation rates of helium. First, nanocomposites were prepared with different amounts of commercial availably graphene nanoplatelets using a semi-industrial-scale compounder. Subsequently, films were produced by compression molding at different temperatures, as well as by flat film extrusion. The extruded films were annealed at different temperatures and durations. In order to investigate the effect of thermal treatment on barrier properties in correlation to thermal, structural, and morphological properties, the films were characterized by differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS), optical microscopy (OM), transmission electron microscopy (TEM), melt rheology measurements, and permeation measurements. In addition to structural characterization, mechanical properties were investigated. The results demonstrate that the permeation rate is strongly influenced by the processing conditions and the filler content. If the filler content is increased, the permeation rate is reduced. The annealing process can further enhance this effect.

Preparation and Property of Al87Ce3Ni8.5Mn1.5 Nanophase Amorphous Composites

2011 ◽  
Vol 412 ◽  
pp. 263-266
Author(s):  
Hong Wei Zhang ◽  
Li Li Zhang ◽  
Feng Rui Zhai ◽  
Jia Jin Tian ◽  
Can Bang Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Phase ◽  
Volume Fraction ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures

The higher mechanical strength of Al87Ce3Ni8.5Mn1.5 nanophase amorphous composites has been obtained with two methods. The first nanophase amorphous composites are directly produced by the single roller spin quenching technology. The method taken for the second nanophase amorphous composites is at first to obtain amorphous single-phase alloy, followed by annealed at different temperatures .The formative condition, the microstructure, the particle size, the volume fraction of α-Al phase and microhardness of nanophase amorphous composites etc have been investigated and compared by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The microstructure of composites produced by the second method is higher than the former, the fabricated material structure of the system is more uniform and the process is easier to control.

scholarly journals Nucleation of the β-polymorph in Composites of Poly(propylene) and Graphene Nanoplatelets

2019 ◽  
Vol 3 (2) ◽  
pp. 38 ◽  
Author(s):  
Valentina Guerra ◽  
Chaoying Wan ◽  
Tony McNally
Keyword(s):  
Graphene Nanoplatelets ◽  
Laboratory Scale ◽  
Degree Of Crystallinity ◽  
Mixing Efficiency ◽  
Scanning Calorimetry ◽  
Dsc Measurements ◽  
Β Phase ◽  
A Value ◽  
Twin Screw ◽  
Poly Propylene

The effects of graphene nanoplatelets (GNPs) on the nucleation of the β-polymorph of polypropylene (PP) were studied when melt-mixed at loadings of 0.1–5 wt % using a laboratory scale twin-screw (conical) extruder and a twin-screw (parallel) extruder with L/D = 40. At low GNP loadings (i.e., ≤0.3 wt %), the mixing efficiency of the extruder used correlated with the β-nucleating activity of GNPs for PP. GNP agglomeration at low loadings (<0.5 wt %) resulted in an increase in the β-phase fraction (Kβ) of PP, as determined from X-ray diffraction measurements, up to 37% at 0.1 wt % GNPs for composites prepared using a laboratory scale twin-screw (conical) extruder. The level of GNP dispersion and distribution was better when the composites were prepared using a 16-mm twin-screw (parallel) extruder, giving a Kβ increase of 24% upon addition of 0.1 wt % GNPs to PP. For GNP loadings >0.5 wt %, the level of GNP dispersion in PP did not influence the growth of β-crystals, where Kβ reached a value of 24%, regardless of the type of extruder used. From differential scanning calorimetry (DSC) measurements, the addition of GNPs to PP increased the crystallization temperature (Tc) of PP by 14 °C and 10 °C for the laboratory scale extruder and 16-mm extruder, respectively, confirming the nucleation of PP by GNPs. The degree of crystallinity (Xc%) of PP increased slightly at low GNP additions (≤0.3 wt %), but then decreased with increasing GNP content.

Superplastic Deformation and Viscous Flow in an Zr-Based Metallic Glass at 410°C

1998 ◽  
Vol 554 ◽  
Author(s):  
T. G. Nieh ◽  
J. G. Wang ◽  
J. Wadsworth ◽  
T. Mukai ◽  
C. T. Liu
Keyword(s):  
Strain Rate ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Single Strain ◽  
Transmission Electron ◽  
Heat Treated ◽  
Different Temperatures

AbstractThe thermal properties of an amorphous alloy (composition in at.%: Zr-10Al-5Ti-17.9Cu-14.6Ni), and particularly the glass transition and crystallization temperature as a function of heating rate, were characterized using Differential Scanning Calorimetry (DSC). X-ray diffraction analyses and Transmission Electron Microscopy were also conducted on samples heat-treated at different temperatures for comparison with the DSC results. Superplasticity in the alloy was studied at 410°C, a temperature within the supercooled liquid region. Both single strain rate and strain rate cycling tests in tension were carried out to investigate the deformation behavior of the alloy in the supercooled liquid region. The experimental results indicated that the alloy did not behave like a Newtonian fluid.

Analysis of Ageing Precipitation Behavior of an Aluminum Alloy

2014 ◽  
Vol 488-489 ◽  
pp. 243-247
Author(s):  
Hong Xing Liu ◽  
Jian Bo Zhang ◽  
Qi Ming Liang ◽  
Hai Jun Hu
Keyword(s):  
Electrical Conductivity ◽  
Ageing Time ◽  
Precipitation Behavior ◽  
Scanning Calorimetry ◽  
Exothermic Reactions ◽  
Transmission Electron ◽  
Different Temperatures ◽  
One Step ◽  
Electrical Conductivity Change

The characterization of Al-Cu-Mg-Ag alloy with high Cu:Mg in the process of one-step ageing at the different temperatures has been studied by hardness, electrical conductivity test combining with transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results show that one endothermic and three exothermic reactions are involved in the curve of DSC experiment for a sample quenched from 520°C. Four samples were aged at the different temperatures greater or less than the peak temperatures of the four reactions. Hardness and electrical conductivity change slowly with ageing time at the low temperature and change fast at the high temperature. GP zones at {100} ɑ planes are the main precipitates in the microstructure of the sample aged at 80°C. Ω and θ phases dominant the microstructure of the samples aged at 170°C, 230°C and 280°C. In addition, the size of precipitates increases fast when the sample aged at higher temperatures.

scholarly journals Application Properties Analysis as a Dielectric Capacitor of End-of-Life Tire-Reinforced HDPE

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2675 ◽  
Author(s):  
Marc Marín-Genescà ◽  
Jordi García-Amorós ◽  
Ramon Mujal-Rosas ◽  
Lluís Massagués Vidal ◽  
Xavier Colom Fajula
Keyword(s):  
Carbon Black ◽  
End Of Life ◽  
Polymeric Composite ◽  
Interfacial Polarization ◽  
Morphological Properties ◽  
Electrical Behavior ◽  
Scanning Calorimetry ◽  
Low Frequencies ◽  
Vulcanized Rubber ◽  
Different Temperatures

The purpose of the present research is to obtain waste of polymeric composite as an insulator capacitive application. Rubber materials, once they end their useful life, may be difficult to reuse or recycle. At present, research only uses one tire recycling method, which involves grinding and separating steel and fibers from vulcanized rubber, and then using the rubber particles for industrial capacitors. The methodology for this research is to compare the permittivity (ε′ and ε″) between high-density polyethylene (HDPE) and the polymer matrix compound, consisting of an HDPE polymeric matrix blended with end-of-life tire particles (ground tire rubber (GTR)), to analyze the feasibility of using such tires as electrically insulating materials (dielectrics). The incorporation of carbon black in the GTR compounds modifies conductivity; GTRs carry a significant amount of carbon black, and therefore some electrical properties may change significantly compared to highly insulating polymer substrates. The performed experimental study is based on a dynamic electric analysis (DEA) test developed in the frequency range of 10−2 Hz to 3 MHz and at different temperatures (from 35 to 70 °C) of different samples type: HDPE neat and HDPE compounds with 10%, 20% and 40% of GTR loads. A sample’s electrical behavior is checked for its dependence on frequency and temperature, focused on the permittivity property; this is a key property for capacitive insulators and is key for examining the possible applications in this field, for HDPE + GTR blends. Results for the permittivity behavior and the loss factor show different electrical behavior. For a neat HDPE sample, no dependence with frequency nor temperature is shown. However, with the addition of 10%, 20%, and 40% amount of GTR the HDPE compounds show different behaviors: for low frequencies, interfacial polarization relaxation is seen, due to the Maxwell–Wagner–Sillars (MWS) effect, performed in heterogeneous materials. In order to analyze thermal and morphological properties the differential scanning calorimetry (DSC) test and scanning electron microscopy (SEM) have been used. Results obtained show that adding waste tire particles in an HDPE matrix allows HDPE + 40% GTR blends to act as a dielectric in capacitors, increasing the capacitor dielectric efficiency in the low frequencies due to the MWS effect, which increases the dielectric constant.

scholarly journals Ethylene-Octene Copolymers/Organoclay Nanocomposites: Preparation and Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Alice Tesarikova ◽  
Dagmar Merinska ◽  
Jiri Kalous ◽  
Petr Svoboda
Keyword(s):  
Barrier Properties ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Uv Aging ◽  
Dynamical Mechanical Analysis ◽  
Elongation At Break ◽  
X Ray ◽  
Transmission Electron ◽  
Nucleation Agents

Two ethylene-octene copolymers with 17 and 45 wt.% of octene (EOC-17 and EOC-45) were compared in nanocomposites with Cloisite 93A. EOC-45 nanocomposites have a higher elongation at break. Dynamical mechanical analysis (DMA) showed a decrease oftan⁡δwith frequency for EOC-17 nanocomposites, but decrease is followed by an increase for EOC-45 nanocomposites; DMA showed also increased modulus for all nanocomposites compared to pure copolymers over a wide temperature range. Barrier properties were improved about 100% by addition of organoclay; they were better for EOC-17 nanocomposites due to higher crystallinity. X-ray diffraction (XRD) together with transmission electron microscopy (TEM) showed some intercalation for EOC-17 but much better dispersion for EOC-45 nanocomposites. Differential scanning calorimetry (DSC) showed increased crystallization temperatureTcfor EOC-17 nanocomposite (aggregates acted as nucleation agents) but decreaseTcfor EOC-45 nanocomposite together with greatly influenced melting peak. Accelerated UV aging showed smaller C=O peak for EOC-45 nanocomposites.

scholarly journals Preparation and Properties of SBR Composites Containing Graphene Nanoplatelets Modified with Pyridinium Derivative

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5407
Author(s):  
Magdalena Gaca ◽  
Cyril Vaulot ◽  
Magdalena Maciejewska ◽  
Magdalena Lipińska
Keyword(s):  
Ionic Liquid ◽  
Textural Properties ◽  
Barrier Properties ◽  
Sem Analysis ◽  
Graphene Nanoplatelets ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Styrene Butadiene ◽  
The Impact

The goal of this work was to study the effect of graphene nanoplatelets (GnPs) modified with ionic liquid (IL) on properties of styrene–butadiene rubber (SBR) composites. GnPs were decorated with IL or were modified in bulk directly during rubber mix preparation. The ionic liquid used was 1-butyl-4-methylpyridinium tetrafluoroborate (BMPFB). The textural properties were studied to confirm surface modification of GnPs with BMPFB. In these investigations, the impact of the concentration of GnPs and the effect of the method of GnPs’ modification with IL on elastomers properties are described. Some thermal measurements (e.g., differential scanning calorimetry and thermogravimetry) were conducted to characterize the thermal stability or the vulcanization process of the investigated samples. Complementary experimental techniques were used to investigate the properties of the obtained elastomers, specifically tensile testing, and electrical and barrier property measurements. The deposition of IL on the GnPs’ surface positively influenced the mechanical and barrier properties of elastomers. However, samples containing graphene nanoplatelets modified from solution were characterized by less electrical conductivity. SEM analysis was additionally performed to investigate GnPs’ dispersion within SBR composites.

Characterization of Al2(WO4)3 Synthesized by Co-Precipitation Method

2014 ◽  
Vol 798-799 ◽  
pp. 85-89 ◽  
Author(s):  
E.S.G. Junior ◽  
P.M . Jardim
Keyword(s):  
Precipitation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Co Precipitation ◽  
Alpha Alumina

Al2(WO4)3was synthesized by co-precipitation using Na2WO4and Al (NO3)3as precursors. After drying the precipitate, it was calcined at different temperatures between 500°C and 800°C. The crystallization and degradation temperatures of the samples were evaluated by means of Differential Scanning Calorimetry (DSC), Thermogravimetry (TG) and X-Ray Diffraction (XRD). It was observed that the crystallization starts at around 600°C, however Transmission Electron Microscopy (TEM) analysis showed that at this temperature the sample is partially amorphous. The degradation of the material starts at around 1200°C and at 1400°C the tungsten oxide has almost completely evaporated and the material is transformed mainly in alpha-alumina.

Effects of polypropylene-g-dibutyl maleate on mechanical and rheological properties of PP/PA6 blends

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Duxin Li ◽  
Baoli Ou ◽  
Demin Jia
Keyword(s):  
Electron Microscopy ◽  
Morphological Properties ◽  
Scanning Calorimetry ◽  
Flow Activation Energy ◽  
Rheological Measurements ◽  
Transmission Electron ◽  
End Groups ◽  
Reactive Groups ◽  
Flow Activation ◽  
Dibutyl Maleate

AbstractThe effects of polypropylene-grafted-dibutyl maleate (PP-g-DBM) used as compatibilizer on mechanical, rheological and morphological properties of polypropylene (PP) and nylon 6 (PA6) blends was systematically investigated in this paper. The results of Molau test, solvent extraction and differential scanning calorimetry (DSC) indicated the formation of PP-g-PA6 in vicinity of interfaces during melting extrusion. Owing to the reaction between the reactive groups of PPg- DBM and amine (-NH2) end groups of PA6, the tensile and impact strength of the PP-g-DBM compatibilized PP/PA6 blends were much higher than that of the uncompatibilized PP/PA6 blends. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results indicated that the domain sizes of the dispersed phase in the compatibilized PP/PA6 blends decreased and the interfaces become more indistinct, which indicated a clear compatibiliting effect was induced by the PP-g-DBM in the immiscible PP/PA6 blends, i.e. the PP-g-DBM was an effective compatibilizer for the PP/PA6 blends. In addition, the rheological measurements showed the PP-g-DBM compatibilized PP/PA6 blends possessed higher pseudo plasticity, melt viscosity and flow activation energy.

Effect of Flow Fields on Morphology of PP/Nano/CaCO3 Composite and Its Rheological Behavior

Materials ◽  
2005 ◽  
Author(s):  
Han-Xiong Huang ◽  
Guo Jiang ◽  
Shan-Qiang Mao
Keyword(s):  
Crystallization Behavior ◽  
Filler Content ◽  
Melt Flow Index ◽  
Flow Fields ◽  
Flow Index ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Twin Screw

Polypropylene (PP)/nano-calcium carbonate (nano-CaCO3) composite was prepared using a co-rotating, intermeshing twin-screw extruder. The effect of flow fields on the morphology of the nanocomposite was investigated. Transmission electron microscopy (TEM) was used for the determination of the morphology in the nanocomposite. The crystallization behavior of the nanocomposite was studied by using differential scanning calorimetry (DSC) and the melt shear viscosity was investigated by a melt flow index tester. The study showed that the flow field, through appropriately combining the type of the screw elements in this work, plays an important role in developing morphology of the nanocomposite. In addition, it was shown that the melt viscosity for the nanocomposite at the filler content less than 10 wt% is lower than that of neat PP.

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