Interaggregate Interaction in Filled Rubber

1990 ◽  
Vol 63 (4) ◽  
pp. 554-566 ◽  
Author(s):  
C. M. Roland ◽  
G. F. Lee

Abstract Measurements of the dynamic properties of carbon-black-filled rubber can be carried out on most instrumentation at strains within the limits of linear behavior; thus, assessments of acoustic performance can readily be made. The equivalence of small-strain dynamic-mechanical testing and acoustic measurements has been demonstrated herein. Blends of NR with a high concentration of 1,2-BR are attractive candidates for damping applications because of the extended frequency range of the glass to rubber transition. One approach to improving the magnitude of the damping is to incorporate high levels of carbon black into the material. Significant interaggregate interaction, promoted for example by a low degree of carbon-black dispersion, will amplify the energy dissipation. The strain dependence of the dynamic properties implicit in such an approach can result in a damping performance sensitive to deformation. The loss tangent rises significantly after such a deformation, while the loss modulus experiences a barely measurable decline. This sensitivity to deformation will thus impact more on constrained layer damping applications than on simple extensional damping. For the materials tested in the present study, complete recovery of the damage to the carbon-black network (which engenders the changes in dynamic mechanical properties) required more than a day at room temperature.

1996 ◽  
Vol 69 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Alan I. Kasner ◽  
Eberhard A. Meinecke

Abstract Cylindrical samples of different levels of porosity were prepared from a model carbon black filled rubber and tested in compression. Dynamic properties were determined with dynamic loads and dynamic displacements superimposed on static loads. Nonlinear stress-strain curves of porous rubber blocks produced a dependence of dynamic properties on the mode of testing. Both storage and loss moduli as well as tan γ were found to depend on the levels of porosity. The loss modulus was found to increase with higher strain levels in porous samples, while the storage modulus changed because of reduced sample stiffness. The dynamic data was in agreement with the results of Goodrich flexometer tests on porous and solid samples. The results suggest that the introduction of porosity reduces service life of rubber parts by providing stress raisers for crack initiation, rather than through changing the dynamic properties.


1996 ◽  
Vol 69 (1) ◽  
pp. 15-47 ◽  
Author(s):  
J. D. Ulmer

Abstract The strain dependencies of dynamic mechanical properties of carbon black-filled rubber compounds have been modeled by Kraus. Evaluation of the Kraus model with carbon black loadings up to 110 phr shows that it provides a fairly good overall description of elastic modulus, G′, as a function of strain, γ. The model description of G′ strain dependence improves with decreased carbon black loading, and is very good with carbon black loadings of 50 phr and less. The model description of viscous modulus strain dependence, G″(γ), is less successful than the G′(γ) description. Several empirical modifications of the viscous modulus model are examined. The most improved model is a very good approximation to viscous modulus over a wide experimental strain-range. Its utility, and that of the Kraus G′(γ) model, are illustrated through calculation of simple shear dynamic properties from torsion property measurements on a solid cylinder, where the strain amplitude varies across the specimen radius. The models allow transformation of the apparent moduli, reported as functions of strain amplitude at the cylinder's outer edge, to their true counterparts, G′(γ) and G″(γ), as functions of uniform strain amplitude. Although the G′(γ) and modified G″(γ) models apply to a wide range of experimental strains, some uncertainties associated with each model's accuracy remain, and there are inconsistencies in the relation of one model to the other. Reservations associated with the models might be resolved through refined treatments of the test specimen geometries.


1982 ◽  
Vol 55 (5) ◽  
pp. 1547-1568 ◽  
Author(s):  
Edwin R. Fitzgerald

Abstract The results reported here demonstrate the feasibility of investigating the dynamic mechanical properties of carbon black-agglomeration networks over wide ranges of temperature and frequency by measurements on carbon black mixed with oil. From the data displayed in Figures 3, 4, 5, and 6, it is evident that the general levels of audiofrequency elastic compliance and modulus, J′ and G′, change more than two orders of magnitude as the temperature is varied between − 12.2 and 50.6°C; the general levels of loss compliance and loss modulus, J″ and G″, change almost as much. A comparison of measurements at 25.2°C made at the beginning and after the conclusion of the measurements at various temperatures (Figure 7) shows little change except for an increase in low frequency values of J″ which are tentatively ascribed to water absorption due to condensation within the sealed measurement apparatus at low temperatures. From this close agreement of before and after compliance values, it is concluded that the large effects of temperature change on the measured dynamic mechanical properties are reversible and essentially independent of thermal history and/or time. The general level of measured dynamic compliance and modulus of the sample of 50 parts by wt. of N299 carbon black in 100 parts by wt. of process oil are also close to those observed for this same carbon black in a cured tire stock for similar temperatures and amounts of black, although the frequency dependences are different. This result agrees with the measurements previously reported by Payne where room temperature values of G′ at 0.1 Hz for carbon black in paraffin oil and for carbon black-butyl rubber were about the same for the same proportion of carbon black. Thus, at low dynamic stress (or strain) amplitudes, the independent carbon-carbon agglomeration network can evidently influence the dynamic mechanical properties of a tire stock as much or more than the cured rubber matrix. The observed broad retardation/relaxation dispersions of compliance and modulus at each temperature clearly cannot be reduced to a common reference temperature by shifts along the frequency axis so that superposition to give composite functions of compliance or modulus over an extended range of frequency is not possible. However, approximate superposition of some compliance and modulus vs. frequency curves to a common reference temperature can be accomplished by vertical shifts indicating that temperature-magnitude reduction may be successful; such reduced curves are shown and treated more extensively in a separate article.


1987 ◽  
Vol 60 (4) ◽  
pp. 591-599 ◽  
Author(s):  
S. Akhtar ◽  
S. S. Bhagawan

Abstract Dynamic mechanical properties such as storage modulus, loss modulus, and loss tangent have been evaluated over a wide range of temperatures for thermoplastic elastomers prepared from blends of NR and HDPE. It was observed that above room temperature, both storage and loss moduli increased and loss tangent decreased as the HDPE content in the blend increased. The effects of dynamic crosslinking and carbon black filler on dynamic mechanical behavior of 70/30 NR/HDPE blend were also examined. Carbon black increased the storage and loss moduli but lowered and broadened the tan δ peak. On the other hand, crosslinking increased storage modulus and decreased the loss modulus and loss tangent, particularly after the NR Tg. The tan δ peak area which appeared at Tg for NR was proportional to the rubber content in the blends.


1995 ◽  
Vol 68 (2) ◽  
pp. 259-266 ◽  
Author(s):  
C. A. Sierra ◽  
C. Galán ◽  
J. M. Gómez Fatou ◽  
V. Ruíz Santa Quiteria

Abstract The interaction between rubber and carbon black in compounds for road tire treads has been analyzed by using mechanical and dynamical measurements in three cured compounds based on SBRs. The rubbers were prepared in solution by anionic polymerization, and coupled with tin compounds in which the carbon-tin bond at the end of the chain may correspond to styryl or butadienyl terminations. The interaction parameter, defined by the ratio of mechanical and dynamic terms, has been used for the first time for the evaluation of the compounds. The SBRs with tin-butadienyl bonds exhibit an improved interaction with the filler, with increasing tin content.


2017 ◽  
Vol 54 (3) ◽  
pp. 543-545 ◽  
Author(s):  
Yusrina Mat Daud ◽  
Kamarudin Hussin ◽  
Azlin Fazlina Osman ◽  
Che Mohd Ruzaidi Ghazali ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
...  

Preparation epoxy based hybrid composites were involved kaolin geopolymer filler, organo-montmorillonite at 3phr by using high speed mechanical stirrer. A mechanical behaviour of neat epoxy, epoxy/organo-montmorillonite and its hybrid composites containing 1-8phr kaolin geopolymer filler was studied upon cyclic deformation (three-point flexion mode) as the temperature is varies. The analysis was determined by dynamic mechanical analysis (DMA) at frequency of 1.0Hz. The results then expressed in storage modulus (E�), loss modulus (E�) and damping factor (tan d) as function of temperature from 40 oC to 130oC. Overall results indicated that E�, E�� and Tg increased considerably by incorporating optimum 1phr kaolin geopolymer in epoxy organo-montmorillonite hybrid composites.


2020 ◽  
Vol 3 (2) ◽  
pp. 36-45 ◽  
Author(s):  
O. Tarasova ◽  
Yu. Yurkin ◽  
A. Toroschin

this work is devoted to the problem of developing vibration-damping polymer materials with high damping properties in a wide temperature range. The study of the effect of modifying additives on the strength, damping, adhesive and cohesive properties of a butyl rubber composite is the aim of this work. The task is to identify the actual temperature, frequency, dynamic and mechanical characteristics of a composite material based on butyl rubber depending on the type and concentration of resins. The key methods for studying this problem is the dynamic mechanical analysis method, aimed at obtaining information about changes in the dynamic properties of polymer materials (bond strength with metal when peeling samples of composites, determining the flow resistance of samples, determining the migration of plasticizer). Due to the established experimental dependences, it was found that the addition of resins (3% by weight) in the composition based on butyl rubber leads to an increase in the damping properties of composite materials, and an increase to (4.25% by weight) leads to their decrease. It was established that the obtained filled mixtures with a high damping peak and good adhesive and strength properties are mixtures with the addition of alkyl phenol-formaldehyde resins.


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