Degradation of Hydrogenated Styrene—Butadiene Rubber at High Temperature

1997 ◽  
Vol 70 (5) ◽  
pp. 855-870 ◽  
Author(s):  
Mousumi De Sarkar ◽  
P. G. Mukunda ◽  
Prajna P. De ◽  
Anil K. Bhowmick
Keyword(s):  
Chain Scission ◽  
Anomalous Behavior ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Ir And Nmr Spectroscopy ◽  
Wide Range ◽  
Styrene Butadiene ◽  
Different Levels ◽  
Thermal Stability Of

Abstract Degradation of hydrogenated styrene—butadiene rubber (HSBR) having different levels of unsaturation has been studied over a wide range of temperatures under anaerobic and aerobic conditions using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), IR and NMR spectroscopy. TGA data indicate higher thermal stability of hydrogenated rubber as compared to SBR in nitrogen, although an anomalous behavior is observed in air due to crosslinking and oxidation of styrene—butadiene rubber (SBR). Isothermal data confirm the above observations. IR and NMR results reveal thermal isomerization, cyclization, oxidation, depolymerization, and chain scission processes. The nature and amount of products formed depend on the time and temperature of degradation and also on the level of hydrogenation of SBR.

scholarly journals Analysis of the Impact on the Mechanical Properties of Modification of Oligohydroxyethers in Organic Solvent Solution with Rubbers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 519
Author(s):  
Vitalii Bezgin ◽  
Agata Dudek ◽  
Adam Gnatowski
Keyword(s):  
Mechanical Properties ◽  
Scientific Paper ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Molecular Weights ◽  
Wide Range ◽  
Strength Tests ◽  
Materials Used ◽  
Styrene Butadiene ◽  
The Impact

This paper proposes and presents the chemical modification of linear hydroxyethers (LHE) with different molecular weights (380, 640, and 1830 g/mol) with the addition of three types of rubbers (polysulfide rubber (PSR), polychloroprene rubber (PCR), and styrene-butadiene rubber (SBR)). The main purpose of choosing this type of modification and the materials used was the possibility to use it in industrial settings. The modification process was conducted for a very wide range of modifier additions (rubber) per 100 g LHE. The materials obtained in the study were subjected to strength tests in order to determine the effect of the modification on functional properties. Mechanical properties of the modified materials were improved after the application of the modifier (rubber) to polyhydroxyether (up to certain modifier content). The most favorable changes in the tested materials were registered in the modification of LHE-1830 with PSR. In the case of LHE-380 and LHE-640 modified in cyclohexanol (CH) and chloroform (CF) solutions, an increase in the values of the tested properties was also obtained, but to a lesser extent than for LHE-1830. The largest changes were registered for LHE-1830 with PSR in CH solution: from 12.1 to 15.3 MPa for compressive strength tests, from 0.8 to 1.5 MPa for tensile testing, from 0.8 to 14.7 MPa for shear strength, and from 1% to 6.5% for the maximum elongation. The analysis of the available literature showed that the modification proposed by the authors has not yet been presented in any previous scientific paper.

scholarly journals Best Practice for De-Vulcanization of Waste Passenger Car Tire Rubber Granulate Using 2-2′-dibenzamidodiphenyldisulfide as De-Vulcanization Agent in a Twin-Screw Extruder

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1139
Author(s):  
Hans van Hoek ◽  
Jacques Noordermeer ◽  
Geert Heideman ◽  
Anke Blume ◽  
Wilma Dierkes
Keyword(s):  
Best Practice ◽  
Chain Scission ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Passenger Car ◽  
Tire Rubber ◽  
Twin Screw ◽  
Styrene Butadiene

De-vulcanization of rubber has been shown to be a viable process to reuse this valuable material. The purpose of the de-vulcanization is to release the crosslinked nature of the highly elastic tire rubber granulate. For present day passenger car tires containing the synthetic rubbers Styrene-Butadiene Rubber (SBR) and Butadiene Rubber (BR) and a high amount of silica as reinforcing filler, producing high quality devulcanizate is a major challenge. In previous research a thermo-chemical mechanical approach was developed, using a twin-screw extruder and diphenyldisulfide (DPDS) as de-vulcanization agent.The screw configuration was designed for low shear in order to protect the polymers from chain scission, or uncontrolled spontaneuous recombination which is the largest problem involved in de-vulcanization of passenger car tire rubber. Because of disadvantages of DPDS for commercial use, 2-2′-dibenzamidodiphenyldisulfide (DBD) was used in the present study. Due to its high melting point of 140 °C the twin-screw extruder process needed to be redesigned. Subsequent milling of the devulcanizate at 60 °C with a narrow gap-width between the mill rolls greatly improved the quality of the devulcanizate in terms of coherence and tensile properties after renewed vulcanization. As the composition of passenger car tire granulate is very complex, the usefulness of the Horikx-Verbruggen analysis as optimization parameter for the de-vulcanization process was limited. Instead, stress-strain properties of re-vulcanized de-vulcanizates were used. The capacity of the twin-screw extruder was limited by the required residence time, implying a low screw speed. A best tensile strength of 8 MPa at a strain at break of 160% of the unblended renewed vulcanizate was found under optimal conditions.

Higher tear strength of EPDM/SBR/TPR composites foam based on double foaming system

2020 ◽  
pp. 009524432093398
Author(s):  
Fuquan Deng ◽  
Hua Jin ◽  
Li Zhang ◽  
Yuxin He
Keyword(s):  
Cell Size ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Polymeric Foam ◽  
Tear Strength ◽  
Crystallization Property ◽  
Plastic Foams ◽  
Styrene Butadiene

Polymeric foam with lightweight and higher impact strength has been used in many fields due to cost reduction and higher toughness. However, it is often difficult to improve their mechanical property especially tear strength. Here, a double foaming system was designed to increase the tear strength of the foamed ethylene–propylene–diene monomer, styrene–butadiene rubber, and thermoplastic rubber (EPDM/SBR/TPR) materials. The cell size of EPDM/SBR/TPR foam and cell distribution were investigated by scanning electron microscopy, which showed that the cells present a bimodal structure. Besides, the tear strength can reach up to 10 N/mm when the density is about 0.40 g/cm3, which is much superior to those of most engineering plastic foams. Meanwhile, the crystallization property of EPDM/SBR/TPR foams was also demonstrated by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry, which indicates that the double foaming system can reduce the crystallization of EPDM/SBR/TPR molecular chains. In addition, the variation of thermal conductivity values depends on the gradual decrease effect of the cell size.

INFLUENCES OF THE COMPATIBILITY OF NR/SSBR AND PHASE-SELECTIVE DISTRIBUTION OF SILICA ON ITS STATIC AND DYNAMIC PROPERTIES

2019 ◽  
pp. 000-000
Author(s):  
Qing-Yuan Han ◽  
Xu Li ◽  
Yu-Chun Li ◽  
You-Ping Wu
Keyword(s):  
Dynamic Properties ◽  
Rolling Resistance ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Bound Rubber ◽  
Tan Δ ◽  
Styrene Butadiene ◽  
Wet Skid Resistance

ABSTRACT The compatibility between solution polymerized styrene–butadiene rubber (SSBR 2466) and natural rubber (NR) is characterized by differential scanning calorimetry and dynamic mechanical thermal analysis. The single glass transition in the entire temperature range of all NR/SSBR blends and good correlation between Tg and SSBR fraction prove the excellent compatibility between SSBR 2466 and NR. With increasing SSBR content, a reduced Payne effect, more homogeneous dispersion of silica, stronger rubber–filler interaction, and more silica selectively distributed in the SSBR phase were determined via rubber-processing analysis, transmission electron microscopy, bound rubber, and thermogravimetric analysis, respectively. The high vinyl content, low styrene content, and end-functionalized structure of SSBR play vital roles in promoting its compatibility with NR and a stronger rubber–silica linkage. The resulting increased tan δ at 0 °C and low tan δ at 60 °C indicates good wet-skid resistance and low rolling resistance by blending SSBR 2466, and 70/30 NR/SSBR is the best balance for producing a “green tire” tread.

A novel chemical technique for compatibility of ethylene-propylene-diene monomer rubber and styrene-butadiene rubber in their blends

2016 ◽  
Vol 49 (4) ◽  
pp. 298-314 ◽  
Author(s):  
Sara Estagy ◽  
Saeed Ostad Movahed ◽  
Soheil Yazdanbakhsh ◽  
Majid Karim Nezhad
Keyword(s):  
Mechanical Properties ◽  
Heat Flow ◽  
Classical Problem ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Ethylene Propylene Diene Monomer ◽  
Scanning Calorimetry ◽  
Covalent Bonds ◽  
Ethylene Propylene ◽  
Styrene Butadiene

The market for commercial polymer blends has grown steadily. A good blend should have strong interphases between different parts of the constituted polymers. Lack of strong interphases is a classical problem of the blend industry. Ethylene-propylene-diene monomer rubber (EPDM)/styrene-butadiene rubber (SBR) blends have a very good aging resistance and good compression sets. However, these rubbers are partially miscible. To improve the miscibility of EPDM and SBR in their blends, a Lewis acid, AlCl3, was used to form EPDM–g–SBR copolymer through Friedel–Crafts reactions. The existence of covalent bonds between EPDM and SBR macromolecules was studied by the cure traces of the blends, that is, ΔTorque, Fourier transform infrared spectrums, differential scanning calorimetry (DSC) heat flow curves, thermogravimetric analysis curves, and scanning electron (SEM) micrographs. Subsequently, several blends with EPDM/SBR ratio of 40/60 and with various AlCl3 amounts were prepared and after curing, their mechanical properties were measured and compared. The results showed covalent bonds formed between SBR–EPDM and SBR–SBR macromolecules. An exothermic change in heat flow in the DSC curve was observed around 111.28°C, which can be attributed to the formation of carbocations in Friedel–Crafts reactions. Adding 2 phr AlCl3 had an efficient effect on EPDM–SBR and or SBR–SBR linkages. The mechanical properties of the cured blends, that is, tensile strength were lower when compared with corresponding values for prepared compound with SBR. Excellent compatibility between the two polymers and strong interphases were observed in SEM micrograph of the cured blend with 1 phr AlCl3.

scholarly journals Dispersibility of Kaolinite-Rich Coal Gangue in Rubber Matrix and the Mechanical Properties and Thermal Stability of the Composites

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1388
Author(s):  
Kenan Zhang ◽  
Hao Zhang ◽  
Linsong Liu ◽  
Yongjie Yang ◽  
Lihui Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Coal Gangue ◽  
Rubber Matrix ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Laser Scattering ◽  
X Ray ◽  
Thermal Stability Of

The aim of this work was to investigate the dispersibility of kaolinite-rich coal gangue in rubber matrix, the mechanical properties and thermal stability of coal gangue/styrene butadiene rubber (SBR) composites, and to compare these properties to those of the same coal gangue but had undergone thermal activation and modification. Several experimental techniques, such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric-differential scanning calorimetry (TG-DSC), laser-scattering particle analyzer were adopted to characterize the coal gangue particles and then the obtained composites. The results demonstrated the raw coal gangue (RCG) was mainly composed of kaolinite. Calcination led to amorphization of thermal activated coal gangue (ACG), increased hydrophilicity and void volume, and decreased pH. The grain size of ACG became coarser than RCG, but ACG turned loose confirmed by higher degree of refinement after grinding. Modification enhanced the hydrophobicity of the coal gangue and improved its dispersibility than fillers without modification. Calcined samples had better dispersibility than uncalcined fillers. Additionally, the coal gangue treated by calcinating, grinding and modifying (MGA) had the best dispersion in rubber matrix. Either calcination or modification could improve the mechanical properties and thermal stability of coal gangue filled rubber, while the performance of MGA reinforced SBR (MGA-SBR) was the best. The enhanced performance of the MGA-SBR was owed to better dispersion of particles as well as stronger interactions between particles and rubber macromolecules.

Preferential Media for Abrasive Flow Machining

2009 ◽  
Vol 131 (1) ◽  
Author(s):  
Kamal K. Kar ◽  
N. L. Ravikumar ◽  
Piyushkumar B. Tailor ◽  
J. Ramkumar ◽  
D. Sathiyamoorthy
Keyword(s):  
Rheological Properties ◽  
Testing Machine ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Abrasive Flow Machining ◽  
Wide Range ◽  
Good Improvement ◽  
Temperature Shear ◽  
Styrene Butadiene ◽  
Surface Improvement

The abrasive flow machining (AFM) is used to deburr, radius, polish and remove recast layer of components in a wide range of applications. Material is removed from the workpiece by a flowing semisolid mass across the surface to be finished. In this study a medium for AFM has been developed from the various viscoelastic carriers and has been contrasted through experimental investigation. The viscoelastic media are selected on the basis of existing media through the studies of thermogravimetric analysis and are characterized by mechanical, as well as rheological, properties with the help of a universal testing machine and a rheometer. The performance of the medium is evaluated through the finishing criteria on a two-way AFM setup. The investigation reveals that the styrene butadiene rubber (SBR) medium gives a good improvement in surface finish. The surface improvement through SBR media is 88%. It is also found that the strain, temperature, shear rate, time of applied constant stress, cyclic loading, etc. have an impact on the mechanical and rheological properties of the newly developed medium, which are ultimately governed by the performance of the medium in the target applications.

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