scholarly journals Development of Liquid Diene Rubber Based Highly Deformable Interactive Fiber-Elastomer Composites

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 390
Author(s):  
Vikram G. Kamble ◽  
Johannes Mersch ◽  
Muhammad Tahir ◽  
Klaus Werner Stöckelhuber ◽  
Amit Das ◽  
...  
Keyword(s):  
Low Temperature ◽  
Research Topic ◽  
Artificial Limbs ◽  
Phase Transformation Temperature ◽  
Elastomeric Matrix ◽  
Intelligent Structures ◽  
Polybutadiene Rubber ◽  
Elastomer Composites ◽  
Vulcanization Process ◽  
Diene Rubber

The preparation of intelligent structures for multiple smart applications such as soft-robotics, artificial limbs, etc., is a rapidly evolving research topic. In the present work, the preparation of a functional fabric, and its integration into a soft elastomeric matrix to develop an adaptive fiber-elastomer composite structure, is presented. Functional fabric, with the implementation of the shape memory effect, was combined with liquid polybutadiene rubber by means of a low-temperature vulcanization process. A detailed investigation on the crosslinking behavior of liquid polybutadiene rubber was performed to develop a rubber formulation that is capable of crosslinking liquid rubber at 75 °C, a temperature that is much lower than the phase transformation temperature of SMA wires (90–110 °C). By utilizing the unique low-temperature crosslinking protocol for liquid polybutadiene rubber, soft intelligent structures containing functional fabric were developed. The adaptive structures were successfully activated by Joule heating. The deformation behavior of the smart structures was experimentally demonstrated by reaching a 120 mm bending distance at an activation voltage of 8 V without an additional load, whereas 90 mm, 70 mm, 65 mm, 57 mm bending distances were achieved with attached weights of 5 g, 10 g, 20 g, 30 g, respectively.

The Influence of Accelerators on EPDM Vulcanizate Structure

1972 ◽  
Vol 45 (5) ◽  
pp. 1348-1365 ◽  
Author(s):  
F. P. Baldwin
Keyword(s):  
Low Temperature ◽  
Crosslink Density ◽  
Low Rank ◽  
Type Synthesis ◽  
Cure Rate ◽  
High Concentration ◽  
Other Information ◽  
The Stability ◽  
Low Sulfur ◽  
Vulcanization Process

Abstract This study of vulcanization has revealed that in low unsaturation EPDM elastomers prepared with ethylidenenorbornene— 1. Stearic acid can be a useful additive for vulcanization. Increasing concentration in the range 0-4 phr leads to faster curing and reduced polysulfidic crosslink concentration at a given crosslink density. 2. Low sulfur and low sulfur/accelerator ratio and/or prolonged curing times are required to generate vulcanizates containing low percentages of polysulfidic crosslinks. 3. At identical crosslink densities, high temperature cures display a lower level of polysulfidic crosslinks than low temperature cures. However, olefin utilization in crosslinking is generally better with low temperature curing. 4. At high sulfur levels, variations in crosslink type distribution resulting from accelerator changes tend to disappear. 5. Mixed acceleration—a dialkylthiocarbamic acid derivative and an accelerator having the benzothiazolylthio radical—appear best suited for the combination of maximizing cure rate and producing stable (lower sulfur rank) crosslinks. Taken together with other information, the results of this study lead to the suggestion that: 6. The stability of the basic accelerator nucleus is influential both on cure rate and on the ability to generate stable crosslinks. 7. The exact structure and concentration of the olefinic moieties present in the polymer have at least as much bearing on the detailed outcome of the vulcanization process as do changes in accelerator. 8. A useful accelerator for these rubbers resulting in the production of vulcanizates containing a high concentration of low rank sulfur crosslink might derive from a MBT type synthesis based on a properly ringalkylated aniline. 9. Some effort devoted to the study of chemicals which may not accelerate crosslinking but could participate in the crosslink shortening process would appear worthwhile.

scholarly journals Thermal Analysis and SEM Microscopy Applied to Studying the Efficiency of Ionic Liquid Immobilization on Solid Supports

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1579 ◽  
Author(s):  
Anna Sowińska ◽  
Magdalena Maciejewska ◽  
Laina Guo ◽  
Etienne Delebecq
Keyword(s):  
Thermal Analysis ◽  
Ionic Liquid ◽  
Carbon Black ◽  
Surface Reactivity ◽  
Solid Supports ◽  
Sem Images ◽  
Elastomeric Matrix ◽  
Dispersion Degree ◽  
Conductive Additives ◽  
Elastomer Composites

Ionic liquids (ILs) are widely used in elastomer composites, primarily as vulcanization activators or accelerators, crosslinkers, conductive additives, or dispersing agents of fillers. The aim of this work was to study the efficiency of ionic liquid immobilization on filler surfaces using different techniques of thermal analysis and scanning electron microscopy (SEM). Ionic liquid, such as 1-decyl 3-methylimidazolium bromide (DmiBr) was grafted on the surface of silica, calcium oxide, and carbon black to improve the dispersion degree of their particles in the elastomeric matrix. Thermal analysis and SEM microscopy revealed a key role in determining the efficiency of the filler modification with ILs dissolved in acetone. Identifying the weight loss associated with thermal decomposition of DmiBr in modified fillers, allowed the calculation of the efficiency of their modification and compare the surface reactivity of studied fillers with DmiBr. Silica and carbon black exhibited high and comparable ability for interaction with ionic liquid. SEM images showed that particles of DmiBr-modified fillers were quite homogeneously dispersed in the elastomer matrix and exhibited good adhesion to the elastomer.

scholarly journals Magneto-Rheological Elastomer Composites. A Review

2020 ◽  
Vol 10 (14) ◽  
pp. 4899 ◽  
Author(s):  
Sneha Samal ◽  
Marcela Škodová ◽  
Lorenzo Abate ◽  
Ignazio Blanco
Keyword(s):  
Magnetic Field ◽  
Smart Materials ◽  
Mechanical Response ◽  
Viscoelastic Behavior ◽  
Shear Mode ◽  
Dynamic Shear ◽  
Elastomeric Matrix ◽  
Elastomer Composites ◽  
Magneto Rheological ◽  
Micro Structures

Magneto-rheological elastomer (MRE) composites belong to the category of smart materials whose mechanical properties can be governed by an external magnetic field. This behavior makes MRE composites largely used in the areas of vibration dampers and absorbers in mechanical systems. MRE composites are conventionally constituted by an elastomeric matrix with embedded filler particles. The aim of this review is to present the most outstanding advances on the rheological performances of MRE composites. Their distribution, arrangement, wettability within an elastomer matrix, and their contribution towards the performance of mechanical response when subjected to a magnetic field are evaluated. Particular attention is devoted to the understanding of their internal micro-structures, filler–filler adhesion, filler–matrix adhesion, and viscoelastic behavior of the MRE composite under static (valve), compressive (squeeze), and dynamic (shear) mode.

Low Temperature Formation of Ferroelectric thin Films

1992 ◽  
Vol 271 ◽  
Author(s):  
Chi Kong Kwok ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Lead Zirconate Titanate ◽  
Transformation Temperature ◽  
Perovskite Phase ◽  
Lead Zirconate ◽  
Phase Transformation Temperature ◽  
Seeding Layer ◽  
Rate Limiting Step ◽  
Nucleation Sites

ABSTRACTTwo novel processes have been developed to lower the transformation temperature of ferroelectric lead zirconate titanate (PZT) thin films with high Zr/Ti ratio. One process makes use of high pressure and the other process uses seeding to encourage the transformation.A previous study has shown that nucleation is the rate-limiting step for the perovskite formation. Therefore, any process that enhances the kinetics of the nucleation will likely decrease the transformation temperature. In this process, a very thin seeding layer, which has a low effective activation energy for perovskite formation, is used to provide nucleation sites needed for the low temperature perovskite formation. In this study, the pyrochlore to perovskite phase transformation temperature of PbZrxTi1−xO33 films of high Zr/Ti ratio (e.g. x = 53/47) can be lowered by as much as 100°C.

scholarly journals Development and testing of controlled adaptive fiber-reinforced elastomer composites

2016 ◽  
Vol 88 (3) ◽  
pp. 345-353 ◽  
Author(s):  
Chokri Cherif ◽  
Rico Hickmann ◽  
Andreas Nocke ◽  
Matthias Schäfer ◽  
Klaus Röbenack ◽  
...  
Keyword(s):  
Smart Materials ◽  
Longitudinal Direction ◽  
Loop Control ◽  
Elastomeric Matrix ◽  
Control Automation ◽  
Glass Fiber Reinforcement ◽  
Flow Through ◽  
Elastomer Composites ◽  
Set Up ◽  
High Deformability

The integration of shape memory alloys (SMAs) into textile-reinforced composites produces a class of smart materials whose shape can be actively influenced. In this paper, Ni-Ti SMA wires are inserted during the weaving of a glass fiber reinforcement textile. This “active” reinforcement is then combined with an elastomeric matrix to produce a highly flexible composite sheet, which maintains high rigidity in the longitudinal direction. By activating the SMAs, high deflection ratios of up to 35% (relative to the component's length) are achieved. To adjust the composite's deflection to defined values, a closed-loop control is set up to adjust the current flow through the SMA wires. A control algorithm is designed and evaluated for several test cases. The high deformability and the controllable behavior show the high potential of these materials for applications such as aerodynamic flow control, automation and architecture.

Development of MgCo2O4–BaCO3 composites as microwave catalysts for the highly effective direct decomposition of NO under excess O2 at a low temperature

2019 ◽  
Vol 9 (16) ◽  
pp. 4276-4285 ◽  
Author(s):  
Wentao Xu ◽  
Qige Wang ◽  
Kang Peng ◽  
Fengtao Chen ◽  
Xue Han ◽  
...  
Keyword(s):  
Low Temperature ◽  
Decomposition Reaction ◽  
Research Topic ◽  
Direct Decomposition ◽  
No Decomposition ◽  
Highly Effective ◽  
Decomposition Of No

The catalytic NO decomposition reaction is a hot research topic.

New Accelerators for Blends of EPDM

1971 ◽  
Vol 44 (4) ◽  
pp. 1065-1079 ◽  
Author(s):  
R. P. Mastromatteo ◽  
J. M. Mitchell ◽  
T. J. Brett
Keyword(s):  
Low Temperature ◽  
Resistance Level ◽  
Rubber Blends ◽  
Oil Resistance ◽  
Rubber Compounds ◽  
Alkyl Substitution ◽  
Diene Rubber ◽  
Selection Of

Abstract Through the use of accelerators containing higher alkyl substitution, we have been able to attain improved properties of EPDM diene rubber blends. EPDM/NBR blends vulcanized with sulfur cure systems employing these accelerators compete favorably with CR compounds in heat aging; have essentially the same oil resistance level, and exhibit better low temperature properties. These blends are highly ozone resistant, easy processing, and safe. Because of the versatility of meeting a desired combination of properties by variations both in the ratios of NBR to EPDM and in the selection of the particular grade of each elastomer, these blends will fulfill many sophisticated elastomer applications. These accelerators can also be used to provide non-blooming cure systems for EPDM compounds and safer ultrafast cure systems for diene rubber compounds. We feel that this advance in property improvement in diene rubber EPDM blends through the use of these new accelerators is only the beginning of a whole new compounding technique for blending.

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