ENHANCING THE REVERSION RESISTANCE, CROSSLINKING DENSITY AND THERMO-MECHANICAL PROPERTIES OF ACCELERATED SULFUR CURED CHLOROBUTYL RUBBER USING 4,4′-BIS (MALEIMIDO) DIPHENYL METHANE

2019 ◽  
Vol 92 (1) ◽  
pp. 110-128 ◽  
Author(s):  
Shibulal Gopisathi ◽  
Changsin Park ◽  
Yang Il Huh ◽  
Jinseok Jeon ◽  
Chang Hyun Yun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Crosslink Density ◽  
Kinetic Studies ◽  
Crosslinking Density ◽  
Low Level ◽  
Compression Set ◽  
Higher Temperature ◽  
Chlorobutyl Rubber

ABSTRACT Vulcanizates of chlorobutyl rubber (CIIR) with the accelerated sulfur generally exhibit poor crosslinking density owing to the low level of unsaturation in the backbone of CIIR. Therefore, the sulfur cured CIIR shows inferior thermo-mechanical properties at elevated temperature. In addition to this, the vulcanization of CIIR with accelerated sulfur is limited at higher temperature due to reversion. To solve these problems, 4,4′-bis (maleimido) diphenyl methane (BMDM) was applied as a crosslinking additive along with the accelerated sulfur. The detailed curing studies have proved that the presence of BMDM greatly enhanced the rheometric torque and the reversion resistance while curing CIIR with accelerated sulfur even at higher vulcanization temperature. Moreover, the crosslinking densities of the sulfur cured CIIR have increased by 109% with the use of 1 phr BMDM and further rose to 380% with 5 phr BMDM. The improved crosslink density could enable reduction of the compression set of the sulfur cured CIIR to around 40% at 100 °C when it was vulcanized in the presence of 5 phr BMDM. The kinetic studies revealed that incorporation of this additive does not adversely affect the original vulcanization behavior of CIIR with accelerated sulfur, instead it marginally improved the speed of the vulcanization.

Influence of the micro-structural factors upon thermal and mechanical properties of various bag leathers

2017 ◽  
Vol 52 (3) ◽  
pp. 167-176 ◽  
Author(s):  
AK Mondal ◽  
PK Chattopadhyay
Keyword(s):  
Mechanical Properties ◽  
Morphological Characteristics ◽  
Crosslinking Density ◽  
Structural Factors ◽  
Melamine Formaldehyde ◽  
Elongation At Break ◽  
Indian Origin ◽  
Higher Temperature ◽  
Temperature And Pressure ◽  
Vegetable Tannins

Four different bag leathers, such as, Sheep Bag Leather (SBL), Buffalo Vegetable Tanned Leather (BVTL), Cow Drum Dyed Dry Milled Leather (CDDDML), and Cow Crocodile Print Leather (CCPL), were processed by different methods from respective wet-blues of Indian origin. Thermal degradation pro?le and mechanical properties of the samples were evaluated, and crosslink densities of each sample were measured by ?tment of Mooney-Rivlin equation on stress-strain plots. Morphological characteristics (e.g. ?bre structure, ?bre thickness, splitting etc.) of all the specimens were investigated by image analyses of SEM photomicrographs. The highest crosslinking density for BVTL was attributed to its higher ?bre and ?bril thicknesses coupled with rigorous retanning by vegetable tannins and syntans. Embossing at higher temperature and pressure reduced CCPL’s elongation-at-break value and hence stretchiness possibly due to the development of set properties within the CCPL matrix. SBL was noted to contain huge void spaces that increased its stretchiness, and melamine formaldehyde syntans showed pronounced in?uence in increasing the thermal resistance of both CCPL and CDDDML.Bangladesh J. Sci. Ind. Res. 52(3), 167-176, 2017

scholarly journals Influence of filler system on the cure characteristics and mechanical properties of butyl reclaimed rubber

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6045-6060
Author(s):  
Zafirah Zainal Abidin ◽  
Siti Nur Liyana Mamauod ◽  
Siti Salina Sarkawi ◽  
Nurshamimi Shahirah Binti Saimi
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Crosslink Density ◽  
Rubber Content ◽  
Elongation At Break ◽  
Cure Characteristics ◽  
Compression Set ◽  
Roll Mill ◽  
Mooney Viscosity

This research aimed to elucidate the effect of black and non-black filler systems on the cure characteristics and mechanical properties of butyl reclaimed rubber (BRR). In this study, BRR800 was the BRR investigated. Since reclaimed rubber is not entirely 100% rubber, actually being a mixture of rubber, carbon black, oil, zinc oxide, stearic acid and other compounding ingredients used in the original compounds, the reclaimed rubber content in each system was fixed at 161 parts per hundred (pphr). Each mixture was mixed using a two-roll mill. The fillers used in this study were carbon black and calcium carbonate. The Mooney viscosity, cure characteristics, crosslink density, and mechanical properties, such as hardness, abrasion resistance, compression set, tear strength, rebound resilience, and the tensile properties of the vulcanizates were investigated. The results showed that the Mooney viscosity of BRR800 filled with carbon black was increased effectively and had a faster curing time and higher crosslink density than BRR filled with calcium carbonate. In addition, except for compression set and elongation at break, the mechanical properties of BRR800 with a black filler system were higher than those of BRR800 with a non-black filler system.

scholarly journals A Review of the Concrete Performance at Elevated Temperature Mixed with Rice Husk and Polypropylene Fibre

2021 ◽  
Vol 9 (VII) ◽  
pp. 2083-2090
Author(s):  
Gaurav Pandey
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
Flexural Strength ◽  
Rice Husk ◽  
Vapour Pressure ◽  
Polypropylene Fibre ◽  
Advantages And Disadvantages ◽  
Optimum Content ◽  
Higher Temperature

This paper deals with the effect of addition of various proportion of polypropylene (PP) fibre and rice husk on the properties of concrete. A lot of experiments were conducted by different authors to explore the effect of raw rice husk and PP fibre and rice husk on tensile, compressive, flexural strength under different temperature condition. The objective of these experiments was to study the effect of polypropylene fibre and raw rice husk at different varying content and to find the optimum content of such admixtures. Concrete specimens were tested at different curing level to check mechanical properties of concrete. A detailed study was carried out at different high temperature conditions. Result shows polypropylene fibre provide a scape matrix to scape excess vapour pressure developed at higher temperature along with reinforcing properties. Rice husk works as a great insulating agent and also enhances the inert properties of concrete. With the various advantages and disadvantages of PP fibre and RRH, this paper is focusing on how there can be an establishment of a certain proportion which makes concrete thermally insulated maintaining higher strength.

850.0 and 852.0 ALUMINUM ALLOY BEARING BARS

Alloy Digest ◽  
1988 ◽  
Vol 37 (9) ◽  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Heat Treating ◽  
Light Metal ◽  
General Purpose ◽  
High Ductility ◽  
Higher Temperature ◽  
Bearing Alloy

Abstract 850.0 ALUMINUM Alloy can be considered the general purpose light metal bearing alloy. Its good thermal conductivity keeps operating temperatures low. It has high ductility. In many applications it has been found to be superior to steel backed bearings. 852.0 ALUMINUM Alloy has higher mechanical properties making it suitable for heavier load and higher temperature applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength. It also includes information on corrosion resistance as well as heat treating and machining. Filing Code: Al-290. Producer or source: Federated Bronze Products Inc..

scholarly journals Effect of Elevated Temperature on Mechanical Properties of High-Volume Fly Ash-Based Geopolymer Concrete, Mortar and Paste Cured at Room Temperature

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1473
Author(s):  
Jun Zhao ◽  
Kang Wang ◽  
Shuaibin Wang ◽  
Zike Wang ◽  
Zhaohui Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Residual Strength ◽  
Elevated Temperatures ◽  
High Volume ◽  
Sem Analysis ◽  
Geopolymer Concrete ◽  
Ordinary Concrete ◽  
Exposure Temperature

This paper presents results from experimental work on mechanical properties of geopolymer concrete, mortar and paste prepared using fly ash and blended slag. Compressive strength, splitting tensile strength and flexural strength tests were conducted on large sets of geopolymer and ordinary concrete, mortar and paste after exposure to elevated temperatures. From Thermogravimetric analyzer (TGA), X-ray diffraction (XRD), Scanning electron microscope (SEM) test results, the geopolymer exhibits excellent resistance to elevated temperature. Compressive strengths of C30, C40 and C50 geopolymer concrete, mortar and paste show incremental improvement then followed by a gradual reduction, and finally reach a relatively consistent value with an increase in exposure temperature. The higher slag content in the geopolymer reduces residual strength and the lower exposure temperature corresponding to peak residual strength. Resistance to elevated temperature of C40 geopolymer concrete, mortar and paste is better than that of ordinary concrete, mortar and paste at the same grade. XRD, TGA and SEM analysis suggests that the heat resistance of C–S–H produced using slag is lower than that of sulphoaluminate gel (quartz and mullite, etc.) produced using fly ash. This facilitates degradation of C30, C40 and C50 geopolymer after exposure to elevated temperatures.

scholarly journals The Effect of Long-Term Impact of Elevated Temperature on Changes in Microstructure and Mechanical Properties of HR3C Steel

2016 ◽  
Vol 61 (2) ◽  
pp. 761-766 ◽  
Author(s):  
A. Zieliński ◽  
M. Sroka ◽  
A. Hernas ◽  
M. Kremzer
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
X Ray ◽  
Qualitative And Quantitative ◽  
Microstructure And Mechanical Properties ◽  
Transmission Electron ◽  
Quantitative Identification ◽  
Working Parameters ◽  
Long Term Impact

Abstract The HR3C is a new steel for pressure components used in the construction of boilers with supercritical working parameters. In the HR3C steel, due to adding Nb and N, the compounds such as MX, CrNbN and M23C6 precipitate during service at elevated temperature, resulting in changes in mechanical properties. This paper presents the results of microstructure investigations after ageing at 650, 700 and 750 °C for 5,000 h. The microstructure investigations were carried out using scanning and transmission electron microscopy. The qualitative and quantitative identification of the existing precipitates was carried out using X-ray analysis of phase composition. The effect elevated temperature on microstructure and mechanical properties of the examined steel was described.

Microstructure Evolution and Mechanical Properties of an Al-Cu-Mg Alloy at Elevated Temperature

2014 ◽  
Vol 1004-1005 ◽  
pp. 148-153
Author(s):  
Min Hao ◽  
Ji Gang Ru ◽  
Ming Liu ◽  
Kun Zhang ◽  
Liang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Shear Fracture ◽  
S Phase ◽  
Mg Alloy ◽  
Transmission Electron ◽  
Fracture Features ◽  
Scanning Electron

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to study the microstructure and mechanical behavior of an Al-Cu-Mg alloy after tensile test at 125°C, 150°C, 175°C and 200 °C, respectively. The yield strength and ultimate tensile strength decreased with the increase of temperature, while the elongation increased firstly and then decreased. The S and S′ precipitate after tension at elevated temperatures. When the temperature was higher than 175°C, the precipitate coarsens rapidly. The alloys displayed a shear fracture features at elevated temperature. The larger S′ and S phase coarsened and dropped which forming crack in the grain boundaries and precipitate interfaces, resulting in the decrease of the elongation of the alloy.

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