Optimization of Organic Fibres%[Kevlar/Arobocel/Acrylic] in NAO Brake Pad Application and its Effect on Thermal Stability & Friction Characteristics

2012 ◽  
Vol 531-532 ◽  
pp. 8-12
Author(s):  
M.A. Sai Balaji ◽  
K. Kalaichelvan
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Minimum Weight ◽  
Friction Material ◽  
Brake Pad ◽  
Temperature Zone ◽  
Good Thermal Stability ◽  
Friction Testing ◽  
Brake Application ◽  
The Stability

Organic fibres (Kevlar/ Arbocel / Acrylic) have good thermal stability, higher surface area and bulk density. The optimization of organic fibres percentage for thermal behaviour is considered using TGA. The temperature raise during brake application will be between 150-4000 C and this temperature zone is very critical to determine the fade characteristics during friction testing. Hence, three different friction composites are developed with the same formulation varying only the Kevlar, Arbocel and Acrylic fibres which are compensated by the inert filler namely the barites and are designated as NA01, NA02 and NA03 respectively. After the fabrication, the TGA test reveals that the composite NA03 has minimum weight loss. The friction coefficient test rig is then used to test the friction material as per SAE J661a standards. The results prove that the brake pad with minimum weight loss during TGA has higher friction stability. Thus, we can correlate the thermal stability with the stability of friction.

Influence of Steel Fiber on Thermal Stability and Thermal Conductivity in a Semi Metallic Disc Brake Pad Formulation

2012 ◽  
Vol 622-623 ◽  
pp. 1545-1549 ◽  
Author(s):  
V. Thiyagarajan ◽  
K. Kalaichelvan
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Weight Loss ◽  
Steel Fiber ◽  
Minimum Weight ◽  
Testing Machine ◽  
Vital Role ◽  
Brake Pad ◽  
Good Thermal Stability ◽  
Friction Testing

Thermal conductivity and thermal stability plays a vital role on the performance of NAO brake pads . The Steel fiber a semi metallic composition is carried out in this paper to prepare the Non Asbestos Brake Pad. Steel fiber has good thermal stability and bulk density. So the optimization of steel fiber percentage for thermal behaviour is considered using TGA. The temperature rise during brake application will be between 150-4000C and this zone of temperature is very critical to determine the fade characteristics during friction testing. Less weight loss between 150 – 400°C during TGA testing means that it is a better thermally stable product. Hence, three different friction composites were developed with same formulation varying the steel fiber content with the inert filler namely barites and designated as NA01, NA02 and NA03 respectively. After the fabrication of the friction composites, the TGA test revealed that the composite NA01 had minimum weight loss during 160 - 4500C. The composites were then tested for Tribo performance using Constant speed testing machine following SAE J 661a standards. Thus we can correlate the thermal stability with the stability of friction based on minimum weight loss using TGA testing. Hence composite NA01 proved to be the best performer.On another aspect the NA01 has more rotor wear when compared to the other composition in that aspect of rotor wear NA03 is best.

Synthesis, characterization and thermal crosslinking behavior of new poly(aryl ether sulfone)s based on naphthalene isomers

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Zhang Ying ◽  
Zhang Yunhe ◽  
Niu Yaming ◽  
Na Ying ◽  
Jiang Zhenhua
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Glass Transition ◽  
Free Radicals ◽  
Crosslinking Reaction ◽  
Transition Temperatures ◽  
Aryl Ether ◽  
Glass Transition Temperatures ◽  
Good Thermal Stability ◽  
Thermal Crosslinking

AbstractFour new poly(aryl ether sulfone)s containing naphthalene rings were synthesized from 1,5- and 2,7-bis-(4-fluorosulfonyl)naphthalene isomers with different diphenols. These polymers exhibited high glass transition temperatures and good thermal stability. The glass transition temperatures ranged from 220 to 236°C and the 5% weight-loss temperatures were above 423°C. As the four polymers were treated at 300°C, the glass transition temperatures of polymer series a obviously increased and the polymers became insoluble in common organic solvents including NMP, DMAc, and chloroform, etc., but the series b did not, which indicate that a thermal crosslinking reaction via free radicals happened leading to crosslinked polymers

scholarly journals Study of structures and properties of ZnO-Sb2O3-P2O5-Na2O glasses

2014 ◽  
Vol 32 (3) ◽  
pp. 414-418 ◽  
Author(s):  
Yajun Qi ◽  
Zhiqiang Wang ◽  
Shangru Zhai ◽  
Shuwen Jiang ◽  
Hai Lin
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Weight Loss ◽  
Deionized Water ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Structures And Properties ◽  
Thermal Stability Of

AbstractThe influence of ZnO substitution by 0–12 wt.% Na2O on the properties of ZnO-Sb2O3-P2O5-Na2O glasses has been investigated. The structure and properties of the glasses with the composition of (13.86-x)ZnO-57.93Sb2O3-28.21P2O5−x Na2O (x = 0–12 wt.%) were characterized by infrared spectra (IR), X-ray diffraction and differential thermal analysis (DTA). The results of IR indicated an increase in the intensity of symmetric vibrations of P-O-P bond, which was confirmed by the improvement of water durability with the increasing amount of Na2O in the range of 0–10 wt.%. Substitution of 10 wt.% Na2O led to the weight loss of the glass to 5.93 mg/cm−2 after immersion in deionized water at 50 °C for 24 h. The results of XRD showed that the ability of crystallization decreased, indicating the good thermal stability of the glass. The glass containing 8 wt.% Na2O had the best properties in every respect and might be an alternative to lead based glasses for the applications, providing further composition improvement.

scholarly journals Characteristics and kinetic analysis of β-glucosidase (MaBgl) from Mucor ardhlaengiktus RSC1

BioResources ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 1626-1638
Author(s):  
Zhihai Yang ◽  
Liping Wu ◽  
Mingjia Fu ◽  
Qin Li ◽  
Dexiao Ye
Keyword(s):  
Thermal Stability ◽  
Ph Value ◽  
Fermentation Broth ◽  
Hydrolytic Enzymes ◽  
Maximum Velocity ◽  
Exchange Chromatography ◽  
Cellulolytic Enzymes ◽  
Good Thermal Stability ◽  
Initial Ph ◽  
The Stability

Cellulolytic enzymes from fungi are complex compound enzyme structures that generally include three kinds of hydrolytic enzymes, which are called endo-β-1,4-glucanases, exo-β-1,4-glucanases, and β-1,4-glucosidases (β-glucosidases). The fungus Mucor ardhlaengiktus isolated from field rice straw produced a β-glucosidase (MaBgl). Maximal MaBgl production occurred when M. ardhlaengiktus was incubated for 6 days in fermentation liquor at 30 °C and an initial pH of 6. Purified MaBgl was obtained from M. ardhlaengiktus fermentation broth by ammonium sulfate fractional precipitation and DEAE-Sepharose FF ion exchange chromatography. The molecular weight of MaBgl as determined by SDS-PAGE electrophoresis was approximately 72 kDa. The kinetic parameters, Michaelis constant (Km) and maximum velocity (Vmax), of MaBgl were 78.2 μmol/L and 28.5 μmol/(L·min), respectively. Assays of MaBgl produced by M. ardhlaengiktus RSC1 under different conditions were investigated by the 3,5-dinitrosalicylic acid (DNS) assay for glucose. The pH and temperature optima for catalytic activity of MaBgl were pH 4.8 and 50 °C, respectively. MaBgl exhibited good thermal stability in the range of 20 to 30 °C, but the thermal stability of MaBgl decreased rapidly over 60 °C. MaBgl had better pH stability between pH 4.6 and 5.0, and the stability of MaBgl decreased when the pH value was lower or higher than this range.

Organosoluble and transparent cardo polyimides with high Tg derived from 9,9-bis(4-aminophenyl)xanthene

2018 ◽  
Vol 31 (8) ◽  
pp. 909-918 ◽  
Author(s):  
Xiao-Lan Zhang ◽  
Cheng Song ◽  
Mei-Hong Wei ◽  
Zhen-Zhong Huang ◽  
Shou-Ri Sheng
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Glass Transition ◽  
Amic Acid ◽  
Dielectric Constants ◽  
Cutoff Wavelength ◽  
One Pot ◽  
Glass Transition Temperatures ◽  
Good Thermal Stability ◽  
Step Procedure

9,9-Bis(4-aminophenyl)xanthene (BAPX) was prepared simply and effectively via one-pot, two-step procedure using xanthenone and aniline as main substrates. The monomer BAPX was reacted with six aromatic dianhydrides in N, N-dimethylacetamide (DMAc) to yield the corresponding polyimides (PIs) via the poly(amic acid) precursors and subsequent thermal or chemical imidization. The resulting PIs exhibited good thermal stability with glass transition temperatures of 308–348°C, initial decomposition temperatures of 470–510°C, 10% weight loss temperatures of 540–565°C, and char yields of 55–59% at 800°C in nitrogen, respectively. All polymers were amorphous and readily soluble in organic solvents such as N-methyl-2-pyrrolidone and DMAc. The PI films had tensile strengths of 71–92 MPa, tensile moduli of 1.91–2.35 GPa, and elongations at break of 5–13%. Meanwhile, these polymer films also had high optical transparency with a cutoff wavelength in the range of 367–415 nm, lower dielectric constants (3.02–3.34 at 10 MHz), and low water uptake of 0.30–0.52%.

Preparation of sustained-release fragrance based on the cavity structure of β-cyclodextrin and its application in cotton fabric

2018 ◽  
Vol 89 (17) ◽  
pp. 3466-3474 ◽  
Author(s):  
Zuobing Xiao ◽  
Juan Deng ◽  
Yunwei Niu ◽  
Guangyong Zhu ◽  
Jiancai Zhu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Surface Morphology ◽  
Inclusion Complexes ◽  
Slow Release ◽  
Cotton Fabrics ◽  
Gas Chromatography Mass Spectrometry ◽  
Release Time ◽  
Good Thermal Stability ◽  
Cavity Structure ◽  
The Stability

The present study reported the formation of fragrance/β-cyclodextrin (β-CD) inclusion complexes aimed to promote thermal stability and controlled release. Then, the fragrance/β-CD inclusion complexes were applied in cotton fabrics through impregnation to obtain aromatic cotton fabrics. The surface morphology and structures of the fragrance/β-CD inclusion complexes were examined via scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy; these analysis results confirmed the formation of inclusion complexes. The stability tests were performed by thermogravimetric analysis and the results confirmed these inclusion complexes had good thermal stability. The surface morphology of the cotton fabrics impregnated by fragrance/β-CD inclusion complexes were tested by SEM. Slow-release experiments of the aromatic cotton fabrics performed by gas chromatography-mass spectrometry and an electronic nose proved that the cotton fabrics impregnated by fragrance/β-CD inclusion complexes had excellent slow-release properties. Moreover, the continuous aroma release time of the cotton fabrics impregnated by fragrance/β-CD inclusion complexes reached up to 80 days.

Thermal and Fade Aspects of a Non Asbestos Semi Metallic Disc Brake Pad Formulation with Two Different Resins

2012 ◽  
Vol 622-623 ◽  
pp. 1559-1563
Author(s):  
M.A. Sai Balaji ◽  
K. Kalaichelvan
Keyword(s):  
Thermal Stability ◽  
Friction And Wear ◽  
Phenolic Resin ◽  
Structural Integrity ◽  
Friction Material ◽  
Performance Criteria ◽  
Brake Pad ◽  
Friction Materials ◽  
Brake Pads ◽  
Thermal Stability Of

The formulation of a brake pad requires the optimization of multiple performance criteria. To achieve a stable and adequate friction (µ), the brake pad materials should have low fade and higher recovery characteristics coupled with less wear and noise. Among the properties mentioned, resistance to fade is very difficult to achieve. The type and amount of resin in the friction material is very critical for structural integrity of the composites. The binder should not deteriorate under any diverse conditions. The thermal stability of friction materials and its capacity to bind its ingredients collectively under diverse conditions depend upon the quality and proportion of resin. The current work evaluates the fade and recovery behaviour of developed friction composites from two different resins which are traditional straight phenolic resin and the alkyl benzene modified phenolic resin. Two brake pads with these different resins were fabricated as per Industrial Standard. TGA is carried between 150 – 4000 C as this zone of temperature is very critical which accounts for the weight loss (Thermal degradation). Friction and wear studies were carried out on a friction coefficient test rig as per SAE J661a standard. The results showed that the fade and wear of the friction materials were closely related to the thermal decomposition of the binder resin and durability of the contact plateaus, which were produced by the compaction of wear debris around hard ingredients on the rubbing surface. It was clearly observed that the friction materials with modified resin showed significant reduction in fade %. Friction materials made with higher thermal stability showed resistance to fade. However wear didn’t show much noticeable changes.

scholarly journals Performance Evaluation of Cellulose Nanofiber with Residual Hemicellulose as a Nanofiller in Polypropylene-Based Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1064
Author(s):  
Mohd Nor Faiz Norrrahim ◽  
Hidayah Ariffin ◽  
Tengku Arisyah Tengku Yasim-Anuar ◽  
Mohd Ali Hassan ◽  
Nor Azowa Ibrahim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Weight Loss ◽  
Tensile Strength ◽  
Performance Evaluation ◽  
Flexural Strength ◽  
Decomposition Temperature ◽  
Cellulose Nanofiber ◽  
Hemicellulose Removal ◽  
Reinforcement Material

Residual hemicellulose could enhance cellulose nanofiber (CNF) processing as it impedes the agglomeration of the nanocellulose fibrils and contributes to complete nanofibrillation within a shorter period of time. Its effect on CNF performance as a reinforcement material is unclear, and hence this study seeks to evaluate the performance of CNF in the presence of amorphous hemicellulose as a reinforcement material in a polypropylene (PP) nanocomposite. Two types of CNF were prepared: SHS-CNF, which contained about 11% hemicellulose, and KOH-CNF, with complete hemicellulose removal. Mechanical properties of the PP/SHS-CNF and PP/KOH-CNF showed an almost similar increment in tensile strength (31% and 32%) and flexural strength (28% and 29%) when 3 wt.% of CNF was incorporated in PP, indicating that hemicellulose in SHS-CNF did not affect the mechanical properties of the PP nanocomposite. The crystallinity of both PP/SHS-CNF and PP/KOH-CNF nanocomposites showed an almost similar value at 55–56%. A slight decrement in thermal stability was seen, whereby the decomposition temperature at 10% weight loss (Td10%) of PP/SHS-CNF was 6 °C lower at 381 °C compared to 387 °C for PP/KOH-CNF, which can be explained by the degradation of thermally unstable hemicellulose. The results from this study showed that the presence of some portion of hemicellulose in CNF did not affect the CNF properties, suggesting that complete hemicellulose removal may not be necessary for the preparation of CNF to be used as a reinforcement material in nanocomposites. This will lead to less harsh pretreatment for CNF preparation and, hence, a more sustainable nanocomposite can be produced.

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