A Master Curve for Amorphous Elastomers Derived from Small and Large Deformations Using Various Instruments

1975 ◽  
Vol 48 (1) ◽  
pp. 69-78 ◽  
Author(s):  
N. Nakajima ◽  
E. A. Collins
Keyword(s):  
Steady State ◽  
Viscoelastic Properties ◽  
High Speed ◽  
Master Curve ◽  
Large Deformations ◽  
Stress Strain ◽  
Strain Measurements ◽  
Mechanical Measurements ◽  
Single Master Curve ◽  
Butadiene Styrene

Abstract Dynamic mechanical measurements, stress—strain measurements, and steady-shear measurements made over a range of temperatures and frequencies or deformation rates are used to characterize the viscoelastic properties of raw elastomers. The measurements involve both small and large deformations. It is shown that the results on either butadiene—acrylonitrile (NBR) or butadiene—styrene (SBR) can be reduced to a single master curve. The instruments and ranges covered included Instron stress—strain (0.2–20 in./min; 25–75°C), Instron capillary (100−104sec −1; 100°C), Rheovibron (110 Hz; 23–156°C), Rheometrics (4×10−2−2.6×102 sec−1; 100°C), MTS high speed tester (267-26 700%/sec; 25–97°C), steady-state Mooney (0.05–20 rpm; 25–150°C) and transient Mooney (0.05 rpm; 25–150°C).

Dynamic Viscoelastic Properties of Raw Butadiene—Acrylonitrile Elastomers

1974 ◽  
Vol 47 (4) ◽  
pp. 778-787 ◽  
Author(s):  
N. Nakajima ◽  
E. A. Collins ◽  
P. R. Kumler
Keyword(s):  
Shear Stress ◽  
Tensile Stress ◽  
Viscoelastic Properties ◽  
High Speed ◽  
Master Curve ◽  
Viscoelastic Behavior ◽  
Master Curves ◽  
Stress Strain ◽  
Strain Measurements ◽  
Using Data

Abstract The dynamic viscoelastic properties of four samples of butadiene—acrylonitrile raw elastomers, were obtained with a Rheovibron at 110 Hz and temperature range of −80 to 160°C. The complex properties were in agreement with the master curves obtained previously from stress-strain measurements. A master curve encompassing 13 decades of time was constructed using data from Mooney rheometer shear stress-strain, MTS high speed tensile stress-strain, and the Rheovibron. The master curve represents the rubbery region of viscoelastic behavior in terms of time, temperature, and the magnitude of deformation up to the breaking point. This study demonstrates that corresponding states can be found between small (ca. 1 per cent) and large deformation up to break (e.g., 1400 per cent).

Master Curve for Tensile Stress—Strain Behavior of Amorphous Elastomers at Small and Large Deformations

1974 ◽  
Vol 47 (2) ◽  
pp. 318-332 ◽  
Author(s):  
N. Nakajima ◽  
E. A. Collins ◽  
H. H. Bowerman
Keyword(s):  
Tensile Stress ◽  
Master Curve ◽  
Large Deformations ◽  
Strain Rates ◽  
Stress Strain ◽  
Strain Behavior

Abstract A master curve scheme for small and large deformations was developed for tensile stress-strain behavior of butadiene—acrylonitrile uncrosslinked elastomers. Measurements were carried out at strain rates of 267 to 26,700 per cent/sec at temperatures of 25 to 97° C.

Rupture Process During Drop Coalescence

2005 ◽  
Author(s):  
H. Aryafar ◽  
H. P. Kavehpour
Keyword(s):  
Physical Properties ◽  
High Speed ◽  
Master Curve ◽  
Digital Camera ◽  
Planar Interface ◽  
Dimensionless Time ◽  
Film Rupture ◽  
Hole Radius ◽  
Dependent Behavior ◽  
Single Master Curve

During the coalescence of a drop with a planar interface, a hole is generated in a microscopic film that separates the drop from the interface. An experimental study has been performed to investigate the time dependent behavior of the radius of the hole generated during coalescence. The study consisted of placing drops of various sizes and physical properties on a planar interface. The coalescence process was recorded from underneath the interface with the aid of a high speed digital camera and a prism. The experiment captured two separate processes, film rupture and the closing of the hole. During the film rupture, the hole radius demonstrated a power law time dependence. Dimensional analysis showed the percentage of time the hole used to reach its maximum radius was approximately constant for all drops. Moreover, all dimensionless drop rupture radii and times fit onto a single master curve and were independent of their physical properties during the opening. However during the closing of the hole, the dimensionless time and radii did not fit a master curve analogous to the hole rupture. The closing of the hole is an entirely different event from the opening and is governed by different parameters.

Viscoelastic and Ultimate Tensile Properties of Styrene-Butadiene-Styrene Block Copolymers

1969 ◽  
Vol 42 (5) ◽  
pp. 1257-1276 ◽  
Author(s):  
T. L. Smith ◽  
R. A. Dickie
Keyword(s):  
Tensile Strength ◽  
Block Copolymers ◽  
High Speed ◽  
Extension Rate ◽  
Stress Strain ◽  
Simple Tension ◽  
Ultimate Properties ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

Abstract A study was made of the stress—strain and ultimate properties in simple tension of an elastomeric styrene—butadiene—styrene block copolymer (Kraton 101) and also of a similar material (Thermolastic 226) that contains about 35% plasticizer as well as inorganic pigments. Stress—strain data were obtained at crosshead speeds from 0.02 to 20 in./min at temperatures from − 40 to 60° C. The relaxation rate, derived from the data at constant extension rates, was about 8% per decade of time for both materials at temperatures from − 40 to about 40° C and at extensions from about 20% up to 400%. Above − 30° C, the shift factor log aT was found to vary linearly with temperature. These findings indicate that the time and temperature dependence of the mechanical properties results primarily from the plastic (or viscoelastic) characteristics of the styrene domains. The tensile strength for Kraton 101 below 40° C is somewhat greater than 4000 psi, sensibly independent of extension rate and temperature. For the highly plasticized Thermolastic 226, the tensile strength at an extension rate of 1.0 min−1 increases from 2200 psi at 0° C to 3600 psi at − 40° C. Above 40° C for Kraton 101 and above 0° C for Thermolastic 226, the tensile strengths are dependent on extension rate and temperature owing to the increased ductility of the styrene domains. The high strength of these materials results from the uniformly dispersed styrene domains of colloidal dimensions. To obtain a crack of sufficient size to satisfy an energetic criterion for self-sustained high-speed propagation, domains must be disrupted. The plastic characteristics of the domains have a controlling effect on crack growth and thus on the ultimate properties of the materials. The strength and extensibility of other elastomers are considered in relation to those of the block copolymers.

Deformational Behavior of Rubber in a Variable Speed “Mooney” Rheometer

1974 ◽  
Vol 47 (2) ◽  
pp. 333-341 ◽  
Author(s):  
N. Nakajima ◽  
E. A. Collins
Keyword(s):  
Steady State ◽  
Master Curve ◽  
Complex Viscosity ◽  
Stress Strain ◽  
Time Curve ◽  
Fundamental Parameters ◽  
Strain Behavior ◽  
Viscosity Curve ◽  
High Shear Rates ◽  
Transient Data

Abstract Because the Mooney Rheometer is widely used and accepted in the laboratory and the plant a closer examination of what it measures is warranted. Although the steady torque value has been converted to steady-state viscosity, the “Mooney torque—time curve” has not been reduced to fundamental parameters. This work, carried out with SBR 1500, treats the initial torque rise as the shear stress-strain behavior analogous to tensile stress-strain. A master curve was constructed from such data obtained at various speeds using a principle of corresponding states. The master curve closely resembles the steady-state viscosity curve and at high shear rates joins the complex viscosity curve measured with the Rheovibron. In addition the use of the transient data enables one to extend the low shear end of the viscosity-rate curve by two decades. The peaks of the torque—time curves strongly suggest that they represent failure points of the material.

The Relation between the Friction and Viscoelastic Properties of Rubber

1964 ◽  
Vol 37 (2) ◽  
pp. 386-403 ◽  
Author(s):  
K. A. Grosch
Keyword(s):  
Viscoelastic Properties ◽  
Master Curve ◽  
Frictional Heating ◽  
Fine Powder ◽  
Molecular Adhesion ◽  
Jump Distance ◽  
Wide Range ◽  
Rubber Surface ◽  
Single Master Curve ◽  
Two Peaks

Abstract This paper describes a study of the friction of several types of rubber against hard surfaces over a wide range of temperatures and sliding velocities. The highest velocity did not exceed a few centimeters per second so that frictional heating was negligible. The results show that the friction increases with the sliding velocity to a maximum value and then falls. The application of the Williams, Landel and Ferry transform shows that the frictional behavior of a rubber sliding at various velocities and temperatures on a given surface can entirely be described by a single master curve and the glass transition temperature of the material. The master curve on a rough abrasive track shows, in general, two peaks—one of these occurs at a velocity related to the frequency with which the track asperities deform the rubber surface. This maximum is absent on a smooth track and thus reflects the deformation losses produced by the passage of the asperities over the rubber surface. The other peak occurs in general at much lower velocities; it coincides in position with the single maximum obtained on a smooth surface. Introduction of a fine powder (MgO) into the interface between the rubber and track eliminates this peak on both smooth and rough surfaces; it is therefore attributed to molecular adhesion. Comparison with the relaxation spectrum of the rubber gives a fundamental jump distance of the order of 60 A. It appears, therefore, that friction arises from adhesion and deformation losses, and that both are directly related to the viscoelastic properties of the rubber.

scholarly journals Astral hydrogels mimic tissue mechanics by aster-aster interpenetration

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qingqiao Xie ◽  
Yuandi Zhuang ◽  
Gaojun Ye ◽  
Tiankuo Wang ◽  
Yi Cao ◽  
...  
Keyword(s):  
Common Core ◽  
Self Assembly ◽  
Master Curve ◽  
Soft Tissues ◽  
Tissue Mechanics ◽  
Fresh Perspective ◽  
Single Master Curve ◽  
Unique Mechanism ◽  
Gel Network

AbstractMany soft tissues are compression-stiffening and extension-softening in response to axial strains, but common hydrogels are either inert (for ideal chains) or tissue-opposite (for semiflexible polymers). Herein, we report a class of astral hydrogels that are structurally distinct from tissues but mechanically tissue-like. Specifically, hierarchical self-assembly of amphiphilic gemini molecules produces radial asters with a common core and divergently growing, semiflexible ribbons; adjacent asters moderately interpenetrate each other via interlacement of their peripheral ribbons to form a gel network. Resembling tissues, the astral gels stiffen in compression and soften in extension with all the experimental data across different gel compositions collapsing onto a single master curve. We put forward a minimal model to reproduce the master curve quantitatively, underlying the determinant role of aster-aster interpenetration. Compression significantly expands the interpenetration region, during which the number of effective crosslinks is increased and the network strengthened, while extension does the opposite. Looking forward, we expect this unique mechanism of interpenetration to provide a fresh perspective for designing and constructing mechanically tissue-like materials.

scholarly journals An Improved Lagrangian-Inverse Method for Evaluating the Dynamic Constitutive Parameters of Concrete

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1871
Author(s):  
Xinlu Yu ◽  
Yingqian Fu ◽  
Xinlong Dong ◽  
Fenghua Zhou ◽  
Jianguo Ning
Keyword(s):  
High Speed ◽  
Inverse Method ◽  
Image Correlation ◽  
Analysis Method ◽  
Stress Strain ◽  
Optical Techniques ◽  
Element Simulation ◽  
Non Linear ◽  
Constitutive Parameters ◽  
Inverse Analysis Method

The dynamic constitutive behaviors of concrete-like materials are of vital importance for structure designing under impact loading conditions. This study proposes a new method to evaluate the constitutive behaviors of ordinary concrete at high strain rates. The proposed method combines the Lagrangian-inverse analysis method with optical techniques (ultra-high-speed camera and digital image correlation techniques). The proposed method is validated against finite-element simulation. Spalling tests were conducted on concretes where optical techniques were employed to obtain the high-frequency spatial and temporal displacement data. We then obtained stress–strain curves of concrete by applying the proposed method on the results of spalling tests. The results show non-linear constitutive behaviors in these stress–strain curves. These non-linear constitutive behaviors can be possibly explained by local heterogeneity of concrete. The proposed method provides an alternative mean to access the dynamic constitutive behaviors which can help future structure designing of concrete-like materials.

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