The Variation with Temperature of the Dynamic Properties of Rubber and Synthetic Rubberlike Materials

1945 ◽  
Vol 18 (2) ◽  
pp. 306-317
Author(s):  
W. P. Fletcher ◽  
J. R. Schofield
Keyword(s):  
Natural Rubber ◽  
Freezing Point ◽  
Dynamic Properties ◽  
Dynamic Compression ◽  
Smooth Curves ◽  
The Subject ◽  
Region 10 ◽  
Increasing Temperature ◽  
Straight Lines ◽  
Rubberlike Materials

Abstract (1) Over the range from 5° to 40° C, the temperature coefficients of the dynamic compression moduli of all the rubber and rubberlike materials studied are negative and fall numerically with increasing temperature. (2) The highest numerical value of this coefficient for natural rubber is −2.7×10−3 per ° C. Neoprene-Gn has a coefficient 3 to 4 times this value and Buna-S about 5 times. Hycar OR-15 shows the highest coefficient of −1.3×10−1 per ° C from 10 to 20° C, the value changing sharply at 20.2° C to −0.14×10−1, which is maintained up to 40° C. (3) Results for Neoprene-E were not reproducible, owing to a type of slow freezing effect. (4) In all cases but Thiokol-RD resilience tended to increase with increasing temperature throughout the range. (5) Resilience-temperature curves for natural rubber, Neoprene-GN, Neoprene-YD, and Buna-S take the form of straight lines intersecting at 20° to 22.5° C. Neoprene-Z shows a similar effect with intersection at 30.5° C. and Hycar OR-15 similarly at 31.5° C. (6) Copolymers of butadiene and acrylonitrile show increasing modulustemperature coefficient, and in the region 10° to 20° C decreasing resilience with increasing acrylonitrile content. The resilience-temperature diagrams for these polymers, except Hycar OR-15, are smooth curves which appear to reach steady values towards the upper end of the temperature range. (7) Thiokol-RD appears to have a freezing-point, under the dynamic conditions employed, somewhere in the region of 15–20° C; there is evidence that Hycar OR-15 shows a similar effect between 0° and 10° C. (8) The relationships enumerated above refer to basic compounds of the various materials. How far the temperature effects may be reduced or modified by suitable compounding is the subject of continuing investigation.

Vibration Properties of Rubberlike Materials Dependence on Temperature

1943 ◽  
Vol 16 (2) ◽  
pp. 400-416 ◽  
Author(s):  
R. B. Stambaugh
Keyword(s):  
Internal Friction ◽  
Natural Rubber ◽  
Critical Temperatures ◽  
Cohesive Forces ◽  
Exponential Law ◽  
Vibration Properties ◽  
Inverse Effect ◽  
Similar Materials ◽  
Straight Lines ◽  
Rubberlike Materials

Abstract 1. The vibration modulus and resilience are independent of the frequency of vibration if the temperature is constant. 2. The internal friction is approximately inversely proportional to the frequency. 3. The modulus decreases as temperature increases. Curves for synthetic stocks at high temperatures are not very different from those of rubber at low temperatures. 4. Resilience rises linearly with temperature. Rubber shows a transition from one slope to another at about 25° C. 5. The dependence of the internal friction of rubber and similar materials on temperature follows the same exponential law as the viscosity of liquids. At certain critical temperatures sudden changes occur in the cohesive forces, which cause a transition from one curve to another. For the natural rubber sample this occurs at about 17° C. 6. The amplitude of vibration has a large inverse effect on the modulus and friction, which cannot be explained by the temperature rise of the sample due to heat generated in it. The effect may be due to nonlinearity of the stress-strain curves. 7. Modulus and friction are affected by temperature in the same way, indicating the dependence of both on some fundamental characteristic of the molecular structure. Natural rubber requires two straight lines for representation on the modulus-friction plot, the junction occurring at about 25° C.

Investigation of Fluid Dynamic Properties of Liquid Field’s Metal

2013 ◽  
Author(s):  
Adam Lipchitz ◽  
Theophile Imbert ◽  
Glenn D. Harvel
Keyword(s):  
Numerical Modeling ◽  
Liquid Metal ◽  
Linear Dependence ◽  
Dynamic Properties ◽  
Fluid Dynamic ◽  
Weight Percent ◽  
Rotational Viscometer ◽  
Liquid States ◽  
Increasing Temperature ◽  
Solid And Liquid States

The density and viscosity Field’s metal is measured in this work and compared to traditional liquid metal coolants such as sodium and lead-bismuth eutectic. Field’s metal is a eutectic of the ternary In-Bi-Sn system. The alloy is by weight percent is 51% indium, 32.5% bismuth and 16.5% tin and possesses a melting temperature of 333 K. This work experimentally measures the density and viscosity of Field’s metal for numerical modeling and thermal hydraulic applications. The density of Field’s metal is measured using a pycnometer. The density is determined for both its solid and liquid states. In its liquid state Field’s metal is found to have a linear dependence with respect to increasing temperature. The viscosity of Field’s metal is measured using a rotational viscometer. The viscosity is measured is to be 27 mPa-s at 353 K, however further investigation is required to determine a trend at higher temperatures.

scholarly journals Dynamics and Protein–Solvent Interactions of Hemoglobin in T and R Quaternary Conformation

2002 ◽  
Vol 16 (3-4) ◽  
pp. 227-233 ◽  
Author(s):  
Chiara Caronna ◽  
Antonio Cupane
Keyword(s):  
Quaternary Structure ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Helical Structure ◽  
Blue Shift ◽  
Peak Frequency ◽  
The Other ◽  
Solvent Interactions ◽  
Reported Data ◽  
Increasing Temperature

In this work we report the thermal behaviour of the amide I′ band of carbonmonoxy and deoxy hemoglobin in 65% v/v glycerolD8/D2O solutions and in the temperature interval 10–295 K. Following recent suggestions in the literature, we analyze the amide I′ band in terms of two components, one at about 1630 cm−1and the other at about 1650 cm−1, that are assigned to solvent‒exposed and buried α‒helical regions, respectively.For deoxy hemoglobin (in T quaternary structure) both components are narrower with respect to carbonmonoxy hemoglobin (in R quaternary structure), while the peak frequency blue shift observed, upon increasing temperature, for the component at about 1630 cm−1is smaller. The reported data provide evidence of the dependence of hemoglobin dynamic properties upon the protein quaternary structure and suggest a more compact α‒helical structure of hemoglobin in T conformation, with reduced population of low‒frequency modes involving the solvent and protein.

Thermoplastic Natural Rubber of Co-Polyamide: Effect of Blend Ratios on Mechanical, Swelling, Dynamic and Morphological Properties

2013 ◽  
Vol 844 ◽  
pp. 89-92
Author(s):  
Boripat Sripornsawat ◽  
Azizon Kaesaman ◽  
Charoen Nakason
Keyword(s):  
Natural Rubber ◽  
Dynamic Properties ◽  
Complex Viscosity ◽  
Continuous Phase ◽  
Morphological Properties ◽  
Elongation At Break ◽  
Degree Of Swelling ◽  
Tan Δ ◽  
Thermoplastic Natural Rubber ◽  
Blend Ratios

Maleated natural rubber (MNR) was synthesized and formulated to prepare thermoplastic natural rubber (TPNR) by blending with co-polyamide (COPA). It was found that 100% modulus, tensile strength, elongation at break, hardness and degree of swelling increased with increasing proportion of COPA. However, degree of swelling and tension set value decreased which reflects enhancing of rubber elasticity. Dynamic properties were also determined by a rotor less oscillating shear rheometer (Rheo Tech MDpt). It was found that increasing proportion of MNR caused increasing of storage modulus and complex viscosity but decreasing tan δ value. Morphological properties were also determined by SEM technique. It was found that the MNR/COPA simple blends with the proportion of rubber 40, 50 and 60 wt% exhibited the co-continuous phase structures.

Effect of Aging Treatment on Dynamic Behavior of Mg-Gd-Y Alloy

2012 ◽  
Vol 13 (2) ◽  
pp. 111-116
Author(s):  
Lin Wang ◽  
Qiao-Yun Qin ◽  
Fan Zhang ◽  
Cheng-Wen Tan
Keyword(s):  
Plastic Deformation ◽  
Rare Earth ◽  
Magnesium Alloy ◽  
Dynamic Behavior ◽  
Deformation Mechanism ◽  
Dynamic Properties ◽  
Dynamic Compression ◽  
Aging Treatment ◽  
Dislocation Slip ◽  
Plastic Deformation Mechanism

Abstract Magnesium alloy is very attractive in many industrial applications due to its low density. The structure-property relationships of the magnesium alloy under quasi-static loading have been extensively investigated. However, the dynamic behavior, particularly the mechanism of high-rate plastic deformation, of the magnesium alloy requires more in-depth investigations. In this paper, the effect of aging treatment on the quasi-static and dynamic properties of a typical rare earth Mg-Gd-Y magnesium alloy is investigated. In particular, the plastic deformation mechanism under dynamic compression loading is discussed. Split Hopkinson Pressure Bar (SHPB) was used to carry out dynamic compression tests with controllable plastic deformation by using stopper rings. The experimental results demonstrate that both static and dynamic properties of the Mg-Gd-Y alloy vary under various aging treatment conditions (under-aged, peak-aged and over-aged conditions), due to two different kinds of second phases: remnant micro size phase from solid solution treatment and nano precipitation from aging treatment. The results of microstructure characterization and statistic analysis of the metallographic phase are presented. The area fraction of the twinned grains increases due to aging treatment and dynamic loading. The main plastic deformation mechanism of the rare earth Mg-Gd-Y magnesium alloy is possibly dislocation slip, rather than twinning for the conventional AZ31 magnesium alloy under high strain rate loading.

scholarly journals Detailed Study on the Mechanical Properties and Activation Energy of Natural Rubber/Chloroprene Rubber Blends during Aging Processes

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Quang Nguyen Trong ◽  
Hung Dang Viet ◽  
Linh Nguyen Pham Duy ◽  
Chuong Bui ◽  
Duong Duc La
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Dynamic Loading ◽  
Dynamic Properties ◽  
Activation Energies ◽  
Rubber Matrix ◽  
Static Properties ◽  
Rubber Blends ◽  
Aging Conditions ◽  
Mechanical Aging

Selection of a suitable thermal aging process could render desirable mechanical properties of the rubbers or blended rubbers. In this work, the effect of the aging processes on the mechanical properties and activation energies of natural rubbers (NR) and NR/chloroprene rubbers (CR) blends with low CR contents (5–10%) was investigated. Three aging processes including heat aging (at 110°C for 22 hours), mechanical aging (under dynamic loading to 140% strain for 16000 cycles), and complex aging (heat and mechanical aging) were studied. The results revealed that the compatibility of CR in natural rubber matrix had a significant effect on the dynamic properties of the blended rubber and negligible effect on the static properties. The changes in activation energies of the blended rubber during aging processes were calculated using Arrhenius relation. The calculated changes (ΔUc, ΔUd, and ΔUT) in activation energies were consistent with the results of mechanical properties of the blended rubber. Interestingly, the change in activation energies using complex aging conditions (ΔUc) was mostly equal to the total changes in activation energies calculated separately from heat aging (ΔUT) and mechanical aging (ΔUd) conditions. This indicates that, in complex aging conditions, the heat and dynamic loading factors act independently on the properties of the blended rubber.

Reinforcement of NR with ENR Modified RHA

2012 ◽  
Vol 581-582 ◽  
pp. 663-667
Author(s):  
Zong Qiang Zeng ◽  
Hong Chao Liu ◽  
He Ping Yu
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Natural Rubber ◽  
Rice Husk Ash ◽  
Dynamic Properties ◽  
Natural Rubber Latex ◽  
Morphological Structure ◽  
Rubber Latex ◽  
Tga Analysis

The rice husk ash (RHA) was first modified with epoxidized natural rubber latex (ENRL) and then blended with natural rubber latex (NRL) to prepare NR/RHA composite. The morphological structure, thermal stability and dynamic properties were studied with multiple instruments. FTIR and TGA analysis showed that ENR was grafted onto the surface of RHA. The composite prepared with modified RHA showed better dispersity and reinforcement compared to the composite with unmodified RHA, and the glass-transition temperature tended to be higher.

TEMPERATURE EFFECT ON THERMOMECHANICAL PROPERTIES OF BERYLLIUM CHALCOGENIDES BeS, BeSe AND BeTe

2006 ◽  
Vol 20 (01) ◽  
pp. 49-61 ◽  
Author(s):  
F. BENKABOU
Keyword(s):  
Elastic Constants ◽  
Dynamic Properties ◽  
Theoretical Calculations ◽  
Thermomechanical Properties ◽  
Structural Dynamic ◽  
Experimental Values ◽  
Beryllium Chalcogenides ◽  
Increasing Temperature ◽  
And Diffusion ◽  
Good Agreement

We have used the molecular-dynamic method for the calculation of the structural, dynamic and elastic properties of group BeS , BeSe and BeTe compounds for temperature ranging from 300 to 1200 K. Tersoff potential has been used to model the interaction between the groups II–VI compound atoms. The structural properties of cubic BeS , BeSe and BeTe have been calculated, and good agreement between the calculated and experimental values have been found. We have also predicted the elastic constants and diffusion coefficients of BeS , BeSe and BeTe . The values found compare very well with the theoretical results. For the temperature range under study, all elastic constants and dynamic properties show a softening with increasing temperature very similar to the theoretical calculations.

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