Method for Estimating the Chemical Crosslink Densities of Cured Natural Rubber and Styrene-Butadiene Rubber

1994 ◽  
Vol 67 (5) ◽  
pp. 854-864 ◽  
Author(s):  
Shirley Lee ◽  
Henry Pawlowski ◽  
A. Y. Coran
Keyword(s):  
Chemical Analysis ◽  
Natural Rubber ◽  
Dynamic Properties ◽  
Loss Modulus ◽  
Styrene Butadiene Rubber ◽  
Dicumyl Peroxide ◽  
Butadiene Rubber ◽  
Chemical Crosslinks ◽  
Styrene Butadiene ◽  
Crosslink Densities

Abstract Chemical crosslink densities of gum and carbon black-filled natural rubber (NR) and styrene-butadiene rubber (SBR) were estimated by using a newly developed rheometer. The rheometer is the Rubber Process Analyzer (RPA 2000) which is designed specifically to measure dynamic properties such as shear storage modulus G′ and shear loss modulus G″ in cured and uncured rubber. It was found that the differences between the G′ values of dicumyl peroxide-cured NR and those of uncured samples yielded estimates of the crosslink densities which were nearly the same as the values inferred by chemical analysis. For TMTD-cured SBR, the same procedure yielded estimates of chemical crosslinks very close to those estimated by a tensile stress-strain method and by NMR. In addition, accelerated sulfur-cured natural rubber was also investigated. The agreement between the crosslink densities of these stocks determined from G′ values and from a solvent-swelling method was very good.

Alpha (Vitrea) Transition in Vulcanized Natural Rubber/Styrene Butadiene Rubber Blends Prepared by Mechanical and Solution Mixing

2012 ◽  
Vol 184 ◽  
pp. 405-410 ◽  
Author(s):  
M. A. Mansilla ◽  
A.A. Ghilarducchi ◽  
H.R. Salva ◽  
A. J. Marzocca
Keyword(s):  
Natural Rubber ◽  
Preparation Method ◽  
Dynamic Properties ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Preparation Methods ◽  
Rubber Blends ◽  
Blend Composition ◽  
Rouse Theory ◽  
Styrene Butadiene

The preparation method of an elastomeric blend can influence the mechanical properties of the vulcanized compound. In this research elastomeric blends composed by natural rubber and styrene butadiene rubber were mixed using two different methods: by mixing in a roll mill and by dissolution of both elastomers in toluene, mixing of both solutions with the curatives and the evaporation of the solvent. Samples with different Natural Rubber/Styrene Butadiene Rubber relation were prepared by both methods and vulcanized at 433K with a system based on sulphur and accelerator (N-t-butyl-2-benzothiazole sulfenamide) up to the time of optimum cure. The blend composition and the preparation methods have a strong influence in the mechanical dynamic properties. Scanning Electron Microscopy observations indicate that, in the blends prepared by the dissolution method, the samples show better miscibility of the constitutive phases than those prepared by the roll milling method. The temperature dependence of the internal friction was studied for each sample using a subresonant forced pendulum at 1 Hz between 190K and 250K. Depending on the blend composition, one or two glass transition temperatures (Tg) associated to the α-relaxation were measured. In the last case each Tgcorresponds to each elastomeric phase of the compound. The loss tangent data for each compound was analyzed using a mixture law of two phases in the frame of the Rouse theory. The adjustment of the data to the proposed model was very good for both preparation method and the whole composition range of the compounds. Then it was possible to obtain the Tg, the main relaxation time and the activation energy values of each compound and, in some samples, the respective values for each elastomeric phase.

Evaluation of Isobutylene-Based Elastomers in a Model Winter Tire Tread

2003 ◽  
Vol 76 (2) ◽  
pp. 348-364 ◽  
Author(s):  
Walter H. Waddell ◽  
Julie H. Kuhr ◽  
Robert R. Poulter
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Dynamic Properties ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Model Compounds ◽  
Styrene Butadiene

Abstract The performance of butyl, chlorobutyl, bromobutyl, and brominated isobutylene-co-para-methylstyrene (BIMS) rubbers were evaluated versus a solution-polymerized styrene-butadiene rubber with 20% bound styrene in model winter tire tread formulations containing natural rubber and butadiene rubber. Isobutylene-based elastomer performance was compared in carbon black-filled and silane-coupled silica-filled systems. Based on laboratory dynamic properties predictive of wet and winter traction, and on DIN abrasion index values, BIMS is the elastomer of choice affording increased tangent delta values between 0 °C and −40 °C, and the highest DIN abrasion index values of the isobutylene-based elastomers. Evaluation of BIMS / NR / BR blends in model compounds show its utility as a tread polymer for improving winter performance.

Effect of Carbon Black Structures towards Heat Build-Up Measurements and its Dynamic Properties

2015 ◽  
Vol 1134 ◽  
pp. 131-137 ◽  
Author(s):  
Mohd Ismail Rifdi Rizuan ◽  
Mohammad Azizol Abdul Wahab ◽  
Ahmad Zafir Romli
Keyword(s):  
Carbon Black ◽  
Dynamic Properties ◽  
Loss Modulus ◽  
Rolling Resistance ◽  
Testing Procedure ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
High Carbon ◽  
Heat Build Up ◽  
Styrene Butadiene

The aim of this study is to investigate the effect of different carbon black structures towards heat build-up measurements and its dynamic properties such as tangent delta, loss modulus and storage modulus on the industrial rubber compounds containing Natural Rubber (NR) and Styrene Butadiene Rubber (SBR). Different carbon black structures were used and characterised with respect to their rheological and physical properties. Heat Build-up test is a testing procedure which is used to measure the rate of heat generated by the rubber vulcanisates when subjected to rapidly oscillating compressive stresses or strain under controlled conditions. It was found that NR compound containing low and high carbon black structures; N375 and N339 produced lower heat generation compared to NR/SBR blends that filled with the same type of carbon black fillers. It shows that NR with low and high carbon black structures exhibits low heat build-up (surface and intrinsic) with a balance of good traction and low rolling resistance for application in tyre.

Tensile Behavior after Oxidative Aging of Gum and Black-Filled Vulcanizates of SBR and NR

1999 ◽  
Vol 72 (4) ◽  
pp. 721-730 ◽  
Author(s):  
G. R. Hamed ◽  
J. Zhao
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Tensile Behavior ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Oxidative Aging ◽  
Prolonged Aging ◽  
Aging Period ◽  
Early Aging ◽  
Styrene Butadiene

Abstract Typical sulfur-cured vulcanizates of styrene-butadiene rubber (SBR) and natural rubber (NR) were prepared, and subjected to air-oven aging at 100 °C. Gum specimens exhibited an initial aging period in which stiffness was unchanged, while tensile strength and strain-to-break were significantly reduced. In contrast, black-filled vulcanizates stiffened during early aging. After intermediate aging times, NR specimens softened, while SBR stiffened. With prolonged aging, all compositions became hard and inextensible.

scholarly journals Dynamo-mechanical analysis of rubbers with mineral fillers in comparison with fillers widely used in the tire industry

2021 ◽  
pp. 05-13
Author(s):  
Oleg K. Garishin ◽  
◽  
Anton Y. Beliaev ◽  
Keyword(s):  
Experimental Testing ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Operating Conditions ◽  
Styrene Butadiene Rubber ◽  
Structural Level ◽  
Butadiene Rubber ◽  
Tire Industry ◽  
Mineral Fillers ◽  
Styrene Butadiene

The work is devoted to the study of nanocomposites based on synthetic (styrene-butadiene) rubber with different fillers not previously used. The issue of using composites with alternative fillers is being investigated. The results of experimental testing and analysis of thermo-visco-elastic behav-ior of styrene-butadiene rubbers filled by various mineral particles of micro and nanosize, as well as pyrolysis products of organic food waste, are presented. The filled elastomers discussed in this work are mainly used in the tire industry to improve the performance of tires. All samples were tested on a dynamo-mechanical analyzer (DMA). Temperature and frequency dependences of the dynamic modulus and loss modulus are plotted for each of the composites. The frequency charac-teristics corresponded to the real range of rotation speeds of the car wheel, and the temperature var-ied from –50 to +50ºC. A comparative analysis of the results obtained was carried out. The struc-tural mechanisms of the filler are not investigated. It is assumed that the principles of operation of the investigated fillers at the structural level are similar to those described in many works for clas-sical fillers. Based on the test results a conclusion about the preferable operating conditions for the considered materials was made.

Thermal conductivity of styrene butadiene rubber compounds with natural rubber prophylactics waste as filler

1999 ◽  
Vol 35 (9) ◽  
pp. 1687-1693 ◽  
Author(s):  
N.S. Saxena ◽  
P. Pradeep ◽  
G. Mathew ◽  
S. Thomas ◽  
M. Gustafsson ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Natural Rubber ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Rubber Compounds ◽  
Styrene Butadiene
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