Development of Porous Polyacrylonitrile Composite Fibers: New Precursor Fibers with High Thermal Stability

2021 ◽  
Vol 2 (4) ◽  
pp. 454-465
Author(s):  
Ehsan Samimi-Sohrforozani ◽  
Sara Azimi ◽  
Alireza Abolhasani ◽  
Samira Malekian ◽  
Shahram Arbab ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Carbon Fibers ◽  
High Performance ◽  
Ternary Phase Diagram ◽  
Decomposition Temperature ◽  
High Thermal Stability ◽  
Composite Fibers ◽  
Porous Composite ◽  
Scanning Calorimetry ◽  
Pan Fibers

Polyacrylonitrile (PAN) fibers with unique properties are becoming increasingly important as precursors for the fabrication of carbon fibers. Here, we suggest the preparation of porous PAN composite fibers to increase the homogeneity and thermal stability of the fibers. Based on the thermodynamics of polymer solutions, the ternary phase diagram of the PAN/H2O/Dimethylformamide (DMF) system has been modeled to introduce porosity in the fibers. Adding a conscious amount of water (4.1 wt.%) as a non-solvent to the PAN solution containing 1 wt.% of graphene oxide (GO), followed by wet spinning, has led to the preparation of porous composite fibers with high thermal stability and unique physicochemical properties. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) results elucidate that PAN/GO/H2O porous composite fibers have a higher thermal decomposition temperature, increased residual weight, reduced heat release rate, and higher crystallinity in comparison with the pristine PAN fibers, being a promising precursor for the development of high-performance carbon fibers. The results show a promising application window of the synthesized PAN fibers in electronic and electrochemical devices.

scholarly journals Effect of Nanofiller Content on Dynamic Mechanical and Thermal Properties of Multi-Walled Carbon Nanotube and Montmorillonite Nanoclay Filler Hybrid Shape Memory Epoxy Composites

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 700
Author(s):  
Muhamad Hasfanizam Mat Yazik ◽  
Mohamed Thariq Hameed Sultan ◽  
Mohammad Jawaid ◽  
Abd Rahim Abu Talib ◽  
Norkhairunnisa Mazlan ◽  
...  
Keyword(s):  
Shape Memory ◽  
High Performance ◽  
Loss Modulus ◽  
Decomposition Temperature ◽  
Hybrid Nanocomposites ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Hybrid Filler ◽  
Dynamic Mechanical ◽  
Tan Δ

The aim of the present study has been to evaluate the effect of hybridization of montmorillonite (MMT) and multi-walled carbon nanotubes (MWCNT) on the thermal and viscoelastic properties of shape memory epoxy polymer (SMEP) nanocomposites. In this study, ultra-sonication was utilized to disperse 1%, 3%, and 5% MMT in combination with 0.5%, 1%, and 1.5% MWCNT into the epoxy system. The fabricated SMEP hybrid nanocomposites were characterized via differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis. The storage modulus (E’), loss modulus (E”), tan δ, decomposition temperature, and decomposition rate, varied upon the addition of the fillers. Tan δ indicated a reduction of glass transition temperature (Tg) for all the hybrid SMEP nanocomposites. 3% MMT/1% MWCNT displayed best overall performance compared to other hybrid filler concentrations and indicated a better mechanical property compared to neat SMEP. These findings open a way to develop novel high-performance composites for various potential applications, such as morphing structures and actuators, as well as biomedical devices.

scholarly journals A Characteristic Study of Polylactic Acid/Organic Modified Montmorillonite (PLA/OMMT) Nanocomposite Materials after Hydrolyzing

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 376
Author(s):  
Su-Mei Huang ◽  
Jiunn-Jer Hwang ◽  
Hsin-Jiant Liu ◽  
An-Miao Zheng
Keyword(s):  
Thermal Stability ◽  
Polylactic Acid ◽  
Decomposition Temperature ◽  
Material Strength ◽  
Scanning Calorimetry ◽  
Hydrolysis Process ◽  
Twin Screw ◽  
Thermal Pressing ◽  
Organophilic Clay ◽  
Mmt Clay

In this study, the montmorillonite (MMT) clay was modified with NH4Cl, and then the structures were exfoliated or intercalated in a polylactic acid (PLA) matrix by a torque rheometer in the ratio of 0.5, 3.0, 5.0 and 8.0 wt%. X-ray diffraction (XRD) revealed that the organic modified-MMT(OMMT) was distributed successfully in the PLA matrix. After thermal pressing, the thermal stability of the mixed composites was measured by a TGA. The mixed composites were also blended with OMMT by a co-rotating twin screw extruder palletizing system, and then injected for the ASTM-D638 standard specimen by an injection machine for measuring the material strength by MTS. The experimental results showed that the mixture of organophilic clay and PLA would enhance the thermal stability. In the PLA mixed with 3 wt% OMMT nanocomposite, the TGA maximum decomposition temperature (Tmax) rose from 336.84 °C to 339.08 °C. In the PLA mixed with 5 wt% OMMT nanocomposite, the loss of temperature rose from 325.14 °C to 326.48 °C. In addition, the elongation rate increased from 4.46% to 10.19% with the maximum loading of 58 MPa. After the vibrating hydrolysis process, the PLA/OMMT nanocomposite was degraded through the measurement of differential scanning calorimetry (DSC) and its Tg, Tc, and Tm1 declined.

Tetragonal CoMn2O4 nanocrystals on electrospun carbon fibers as a high–performance battery–type supercapacitor electrode material

2021 ◽  
Author(s):  
Daniel M. Mijailovic ◽  
Vuk V. Radmilović ◽  
Uros C. Lacnjevac ◽  
Dusica B Stojanovic ◽  
Karen Bustillo ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Electrode Material ◽  
High Performance ◽  
Redox Activity ◽  
Composite Fibers ◽  
Supercapacitor Electrode ◽  
Step Procedure

We herein report a simple two–step procedure for fabricating tetragonal CoMn2O4 spinel nanocrystals on carbon fibers. The battery–type behavior of these composite fibers arises from the redox activity of CoMn2O4...

scholarly journals High-performance La-doped BCZT thin film capacitors on LaNiO3/Pt composite bottom electrodes with ultra-high efficiency and high thermal stability

2019 ◽  
Vol 45 (9) ◽  
pp. 11749-11755 ◽  
Author(s):  
Shangkai He ◽  
Biaolin Peng ◽  
Glenn J.T. Leighton ◽  
Christopher Shaw ◽  
Ningzhang Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
High Performance ◽  
High Efficiency ◽  
High Thermal Stability ◽  
Thin Film Capacitors ◽  
La Doped

scholarly journals Curing Kinetics and Thermal Stability of Epoxy Composites Containing Newly Obtained Nano-Scale Aluminum Hypophosphite (AlPO2)

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 644 ◽  
Author(s):  
Farimah Tikhani ◽  
Shahab Moghari ◽  
Maryam Jouyandeh ◽  
Fouad Laoutid ◽  
Henri Vahabi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
High Performance ◽  
Frequency Factor ◽  
Curing Temperature ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Nano Scale ◽  
Aluminum Hypophosphite ◽  
Thermal Stability Of

For the first time, nano-scale aluminum hypophosphite (AlPO2) was simply obtained in a two-step milling process and applied in preparation of epoxy nanocomposites varying concentration (0.1, 0.3, and 0.5 wt.% based on resin weight). Studying the cure kinetics and thermal stability of these nanocomposites would pave the way toward the design of high-performance nanocomposites for special applications. Scanning electron microscopy (SEM) and transmittance electron microscopy (TEM) revealed AlPO2 particles having domains less than 60 nm with high potential for agglomeration. Excellent (at heating rate of 5 °C/min) and Good (at heating rates of 10, 15 and 20 °C/min) cure states were detected for nanocomposites under nonisothermal differential scanning calorimetry (DSC). While the dimensionless curing temperature interval (ΔT*) was almost equal for epoxy/AlPO2 nanocomposites, dimensionless heat release (ΔH*) changed by densification of polymeric network. Quantitative cure analysis based on isoconversional Friedman and Kissinger methods gave rise to the kinetic parameters such as activation energy and the order of reaction as well as frequency factor. Variation of glass transition temperature (Tg) was monitored to explain the molecular interaction in the system, where Tg increased from 73.2 °C for neat epoxy to just 79.5 °C for the system containing 0.1 wt.% AlPO2. Moreover, thermogravimetric analysis (TGA) showed that nanocomposites were thermally stable.

scholarly journals Structural Transformation of Polyacrylonitrile (PAN) Fibers during Rapid Thermal Pretreatment in Nitrogen Atmosphere

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 63 ◽  
Author(s):  
Wei Dang ◽  
Jie Liu ◽  
Xiaoxu Wang ◽  
Kaiqi Yan ◽  
Aolin Zhang ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Low Cost ◽  
Structural Evolution ◽  
Structural Difference ◽  
Nitrogen Atmosphere ◽  
Thermal Pretreatment ◽  
Scanning Calorimetry ◽  
Light Yellow ◽  
Time And Energy ◽  
Pan Fibers

The modification before the stabilization process could tune the exothermic behavior and the structural evolution of PAN fibers during stabilization. In this study, we demonstrate that a rapid thermal pretreatment in nitrogen can effectively mitigate the exothermic behavior of PAN fibers, such as decreasing the initial temperature, broadening the exothermal peak, and decreasing the nominal heat release during heating the fibers in air. The color of fibers has shown gradual changes from white to light yellow, yellow and brown during thermal pretreatment in nitrogen with the increase of pretreating temperature and time. The differential scanning calorimetry (DSC), Fourier Transform Infrared Spectrometer (FTIR), X-ray diffraction (XRD), and Thermogravimetric Analysis (TG) characterization have been applied to analyze the thermal properties, chemical and physical structural difference between PAN, and thermally pretreated PAN fibers. The thermal pretreatment of PAN fibers in nitrogen could induce cyclization, dehydrogenation, and cross-linking reactions, in which the cyclization play an important role on improving the cyclization index of stabilized PAN fibers. Meanwhile, the pretreatment can result in noticeable changes of the aggregation structure of PAN fibers, as indicated by the increase of crystallinity and crystalline size. These structural modifications can benefit the main cyclization reaction during stabilization and enhance the carbon yield in resultant carbon fibers. The rapid thermal pretreatment in nitrogen could increase efficiency of modification on PAN fibers, and that could save much time and energy. It is beneficial to manufacture low-cost carbon fibers and to spread the applications of carbon fibers.

scholarly journals Effect of Compatibilizer on the Interface Bonding of Graphene Oxide/Polypropylene Composite Fibers

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1283 ◽  
Author(s):  
Miao Miao ◽  
Chunyan Wei ◽  
Ying Wang ◽  
Yongfang Qian
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Loss Modulus ◽  
Composite Fiber ◽  
Mechanical Analysis ◽  
Interfacial Bonding ◽  
Composite Fibers ◽  
Scanning Calorimetry ◽  
Blending Method ◽  
Thermal Stability Of

To improve the interfacial bonding and thermal stability of graphene oxide (GO)/polypropylene (PP) composite fibers, a composite fiber with PP as the matrix, GO as reinforcement and maleic anhydride-grafted PP (PP-g-MAH) as a compatibilizer was prepared by a simple and efficient melt-blending method. The GO content was 0.0–5.0 wt %. According to the Fourier Transform Infrared (FT-IR) spectroscopy results, the interfacial bonding in the PP/MAH/GO composite fibers was improved. The Dynamic Mechanical Analysis (DMA) results show that the addition of GO resulted in better interfacial adhesion and higher storage modulus (E′). The loss modulus (E′′) of the PP/MAH/GO-x composite fibers increased with increasing amount of added GO, whereas the loss factor (tan δ) decreased. GO and PP-g-MAH were analyzed by Thermogravimetric Analysis (TGA). The thermal stability of the composite fibers was improved compared to PP. Differential Scanning Calorimetry (DSC) analysis showed that the addition of PP-g-MAH to the composite fiber improved the interfacial bonding of GO in the PP matrix. Thus, compatibility between the two components was obtained. Based on the Scanning Electron Microscopy (SEM) results, the PP fibers exhibited relative orientation due to the strong crystalline morphology. The rough section, PP/GO blend fiber exhibits a very clear phase separation morphology due to the incompatibility between the two and the compatibility of GO and PP in PP/MAH/GO-3 composite fiber is improved, resulting in the interface between the two has improved.

Heat-resistant and photoluminescent indole-based poly(ether sulfone)s

2017 ◽  
Vol 30 (4) ◽  
pp. 475-479 ◽  
Author(s):  
Wenxuan Wei ◽  
Li Yang ◽  
Guanjun Chang
Keyword(s):  
Thermal Stability ◽  
High Performance ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Condensation Polymerization ◽  
High Glass Transition Temperature ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
High Performance Polymers ◽  
Good Agreement

Indole-based poly(ether sulfone)s (PINESs), as novel high-performance polymers, have been obtained by the condensation polymerization of 4-hydroxyindole and hydroquinone with activated difluoro monomers via a catalyst-free nucleophilic substitution reaction. The structures of the polymers are characterized by means of Fourier transform infrared and proton nuclear magnetic resonance spectroscopy, and the results show good agreement with the proposed structures. Differential scanning calorimetry and thermogravimetric analysis measurements exhibit that polymers possess high glass transition temperature ( Tgs > 245°C) and good thermal stability with high decomposition temperatures ( Tds > 440°C). In addition, due to their special structure, PINESs are endowed with significantly strong photonic luminescence in N, N-dimethylformamide.

Development of Low Phosphorous Engine Oils

2005 ◽  
Author(s):  
K. Patel ◽  
P. B. Aswath ◽  
R. L. Elsenbaumer
Keyword(s):  
Active Ingredient ◽  
High Performance ◽  
Decomposition Temperature ◽  
Fixed Number ◽  
Engine Oil ◽  
Additive Package ◽  
Scanning Calorimetry ◽  
Base Oil ◽  
Lower Weight ◽  
Wear Protection

ZDDP is the industry standard anti wear additive used by oil formulators for the past 50 years to provide the antiwear and load bearing capacity of engine oil. The breakdown of ZDDP results in the formation of sulfides and phosphates which provide anti-wear protection. In addition to its role as an anti-wear additive ZDDP also performs the role of an antioxidant. The performance of ZDDP is reduced by other parts of the additive package which include dispersants, pH stabilizers, and detergents. These constituents stabilize ZDDP and reduce its activity. The breakdown of ZDDP also creates S and P that can poison catalytic converters resulting in higher hydrocarbon and NOx emissions. GF-4 oils have lower ZDDP content to meet federal emission standards. In addition, to meet CAFE´ fuel economy standards, the industry is moving towards lower weight 5W-20 oil. The lower weight base oil coupled with lower ZDDP content have put additional constraints in developing high performance GF-4 oil. An additive package developed by Platinum Research Organization and the Tribology Group at University of Texas at Arlington is evaluated. This additive package enhances the activity of ZDDP and increases its anti-wear performance. This paper presents results from bench top tribology tests that were conducted to evaluate the performance of GF-4 oils with different amounts of ZDDP, additive package and an Fe based active ingredient. Results are discussed with respect to the extent of wear for a fixed number of wear cycles in a ball on cylinder test conducted under boundary conditions. In the presence of FeF3 active ingredient fully formulated oils with as little as 0.01% P exhibits antiwear performance comparable to oils with as much as 0.05% P and oils with 0.05%P are comparable to oils with 0.1%P. Differential scanning calorimetry indicates that the decomposition temperature of ZDDP is reduced by as much as 20°C in the presence of FeF3. This reduced decomposition temperature results in the efficient formation of anti-wear films even with lower ZDDP amounts.

TOUGHMET 2

Alloy Digest ◽  
2013 ◽  
Vol 62 (5) ◽  
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Fracture Toughness ◽  
Wear Resistance ◽  
High Performance ◽  
Mechanical Performance ◽  
High Thermal Stability ◽  
Lead Free ◽  
Plain Bearing ◽  
Ni Alloy

Abstract ToughMet 2 is a high performance, wrought, heat treatable, lead-free strip Cu-Ni alloy that imparts superior mechanical performance and high thermal stability to plain bearing applications. Parts are easily formed and they can be machined either before or after heat treatment. ToughMet alloys are a line of spinodal hardened Cu-Ni anti-galling alloys for bearings capable of performing with a variety of shafting materials and lubricants. The alloys combine a high lubricity with wear resistance in these severe loading conditions. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming and machining. Filing Code: Cu-724. Producer or source: Materion Brush Performance Alloys. Originally published September 2004, revised May 2013.

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