The Hysteresis Temperature and Strain Dependences in Filled Rubbers

2006 ◽  
Vol 79 (1) ◽  
pp. 170-197 ◽  
Author(s):  
Alberto Scurati ◽  
Chenchy J. Lin
Keyword(s):  
Temperature Dependence ◽  
Functional Polymers ◽  
Temperature Hysteresis ◽  
Individual Effect ◽  
Polymer Filler ◽  
Filled Rubbers ◽  
Filler Network ◽  
Dynamic Storage ◽  
Tan Δ ◽  
The Individual

Abstract The strong hysteresis (tan δ) temperature dependence observed in filled compounds containing functional polymers was investigated by studying the individual effect of filler-filler (F-F) and polymer-filler interactions (P-F). Silica filled compounds were prepared by adding n-octyl-triethoxyl or mercatopropyl-trimethoxyl silane. Both silanes are capable of retarding filler flocculation upon heating and give compounds with less developed filler networks either by reducing F-F interactions or by screening filler networks through P-F attachments. The filler network is shown to mediate the low-temperature hysteresis due to the polymer glass transition (Tg) by changing the temperature dependence of the compound dynamic storage modulus (G′). At temperatures far above the Tg, the compound tan δ is governed by mechanisms that control the degree of filler networking. Compounds with less developed networks show weaker strain dependence on G′ and tan δ. Both reduced F-F and increased P-F interactions will give a compound with a less developed network. However, significant reduced tan δ is only found in a system that shows strong P-F interaction due to less energy loss upon deformation by fewer network breakage and increased P-F crosslinks. This is exemplified by comparing the compound loss moduli (G″) of various stocks with corresponding G′ in G-plot (G″ vs. G′).

Semiempirical Relationships between Properties and Loading in Filled Elastomers

1989 ◽  
Vol 62 (5) ◽  
pp. 788-799 ◽  
Author(s):  
A. Pouchelon ◽  
P. Vondracek
Keyword(s):  
Filler Loading ◽  
General Validity ◽  
Elongation At Break ◽  
Filled Elastomers ◽  
Polymer Filler ◽  
Adsorbed Polymer ◽  
Percolation Behavior ◽  
Filled Rubbers ◽  
Filler Network ◽  
Dynamic Storage

Abstract The dynamic storage modulus of uncured silica-filled silicone rubber increases sharply when a critical filler loading is reached. A similar behavior has been observed for the conductivity in the same compounds. The experimental data fit a percolation law fairly well, and microscopy confirms the formation of a filler network according to the percolation model. This behavior depends on a polymer-filler interaction level, suggesting a filler network consisting of filler particles bridged together by adsorbed polymer. It has been found that the percolation threshold coincides with the optimum value of elongation at break of the corresponding vulcanizates. The percolation behavior and the relations between properties of filled rubbers described here were observed in various filled rubbers of quite different compositions. This seems to suggest the general validity of the presented relationships in all elastomers reinforced by particulate fillers.

On the Filler Flocculation in Silica-Filled Rubbers Part I. Quantifying and Tracking the Filler Flocculation and Polymer-Filler Interactions in the Unvulcanized Rubber Compounds

2002 ◽  
Vol 75 (5) ◽  
pp. 865-890 ◽  
Author(s):  
Chenchy J. Lin ◽  
W. L. Hergenrother ◽  
E. Alexanian ◽  
G. G. A. Böhm
Keyword(s):  
Linear Regression Analysis ◽  
Quantitative Characterization ◽  
Polymer Filler ◽  
Rubber Compounds ◽  
On Line ◽  
Filled Rubbers ◽  
Dynamic Storage ◽  
Vulcanization Process ◽  
Flocculation Process

Abstract Filler flocculation was followed for silica filled compounds containing various alkoxy silanes and non-silane type polar additives. The methodology employed in this paper permitted a quantitative characterization of filler flocculation and polymer-filler interactions after heating the compound under conditions that simulated vulcanization. With the addition of trialkoxy silanes, the reduction of filler flocculation and the degree of polymer-filler interactions were found to depend on the type and the concentration of silane added, and on the mixing drop temperature (Td) used. Greater polymer-filler interactions and flocculation suppression were obtained with a compound containing a tetrasulfane when compared to that containing either a disulfane or a monofunctional-silane. Polar additives such as an amine compound and a sugar alcohol did not reduce the silica flocculation during simulated vulcanization because they were dewetted from the silica surface upon heating. The filler flocculation process was monitored by following the change of dynamic storage moduli using an on-line rheometer. The flocculation process order and process constant were extracted from the non-linear regression analysis of the kinetic data. These kinetic parameters were used to quantify the suppression of filler flocculation by the additives used. Filler flocculation was found not to be affected by the vulcanization process because it occurred prior to the onset of cure.

On the Filler Flocculation in Silica and Carbon Black Filled Rubbers: Part II. Filler Flocculation and Polymer-Filler Interaction

2004 ◽  
Vol 77 (1) ◽  
pp. 90-114 ◽  
Author(s):  
Chenchy J. Lin ◽  
Terrence E. Hogan ◽  
William L. Hergenrother
Keyword(s):  
Carbon Black ◽  
Temperature Dependence ◽  
Thermal Annealing ◽  
Elevated Temperatures ◽  
Strong Dependence ◽  
Rolling Resistance ◽  
Tetraethyl Orthosilicate ◽  
Polymer Filler ◽  
End Groups ◽  
Filled Rubbers

Abstract Filler flocculation and polymer-filler interaction in silica and carbon black filled rubbers containing different functional end-groups were investigated. Lithium-hexamethyleneimine initiated polymers terminated with a proton (HMI-P-H), SnCl4 (HMI-P-Sn), and a mixture of SnCl4 and tetraethyl orthosilicate (HMI-P-TEOS) were employed to determine the affinities of various functionalities toward fillers. Reduced filler flocculation was found for compounds of HMI-P-Sn and HMI-P-TEOS after thermal annealing at 171 °C for 15 minutes when compared to the annealed HMI-P-H stock. Curing at the same condition used for annealing gave further suppression of filler flocculation for HMI-P-TEOS stock by increased polymer-filler interaction during cure. Polymer-filler interaction was followed by examining G′ strain dependence and the differences in G′ obtained between HMI-P-Sn or HMI-P-TEOS and HMI-P-H (δG′). This treatment gave a peak maximum in the δG′ plot as a function of strain. The magnitude of the maximum in HMI-P-TEOS stock is double that of HMI-P-Sn stock and increased after thermal annealing. The compound tanδ temperature dependence showed higher hysteresis around the Tg transition and strong dependence at elevated temperatures was found for HMI-P-TEOS stocks. This increased polymer-filler interaction is manifested with increased 0 °C tanδ and reduced 50 °C tanδ which relates to the improved wet traction and rolling resistance for tires.

scholarly journals Kinetical Study, Thermo-Mechanical Characteristics and Recyclability of Epoxidized Camelina Oil Cured with Antagonist Structure (Aliphatic/Aromatic) or Functionality (Acid/Amine) Hardeners

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2503
Author(s):  
Chiara Di Mauro ◽  
Aratz Genua ◽  
Alice Mija
Keyword(s):  
Disulfide Bonds ◽  
Mechanical Characteristics ◽  
Dicarboxylic Acids ◽  
Thermomechanical Properties ◽  
Chemical Recycling ◽  
Camelina Oil ◽  
Ft Ir ◽  
Tan Δ ◽  
The Individual ◽  
First Time

In an attempt to prepare sustainable epoxy thermosets, this study introduces for the first time the idea to use antagonist structures (aromatic/aliphatic) or functionalities (acid/amine) as hardeners to produce reprocessable resins based on epoxidized camelina oil (ECMO). Two kinds of mixtures were tested: one combines aromatic/aliphatic dicarboxylic acids: 2,2′-dithiodibenzoic acid (DTBA) and 3,3′-dithiodipropionic acid (DTDA); another is the combination of two aromatic structures with acid/amine functionality: DTBA and 4-aminophenyl disulfide (4-AFD). DSC and FT-IR analyses were used as methods to analyze the curing reaction of ECMO with the hardeners. It was found that the thermosets obtained with the dual crosslinked mechanism needed reduced curing temperatures and reprocessing protocols compared to the individual crosslinked thermosets. Thanks to the contribution of disulfide bonds in the network topology, the obtained thermosets showed recycling ability. The final thermomechanical properties of the virgin and mechanical reprocessed materials were analyzed by DMA and TGA. The obtained thermosets range from elastomeric to rigid materials. As an example, the ECMO/DTBA704-AFD30 virgin or reprocessed thermosets have tan δ values reaching 82–83 °C. The study also investigates the chemical recycling and the solvent resistance of these vitrimer-like materials.

Innovative Experimental Investigation on the Influences of the Reynolds Number

2017 ◽  
Author(s):  
Jian Gu ◽  
Antonio Carlos Fernandes
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Dimensionless Parameter ◽  
Individual Effect ◽  
Vortex Induced Vibration ◽  
Industry Standards ◽  
Experimental Facilities ◽  
The Individual

The influences of Re (Reynolds number) on the response of vortex induced vibration (VIV) have been studied by previous researches, which indicate the influences should not be ignored. However, due to the limitation of experimental facilities and complexity of the cases, the explicit influence of Re on VIV is still not fully known. Meanwhile, the industry standards also do not supply design reference taking account of Re effects quantitatively. In present work, an innovative dimensionless parameter (denoted as “inertia-viscosity”) is proposed to displace the Re in the dimensionless system, in order to clarify the individual effect of Re. With this method, comparing tests are concisely carried out, and the effectiveness and feasibility are demonstrated. Through the comparing of tests, several remarkable results are obtained.

Condensation Reactions Synthesize Random Polymers

2019 ◽  
Author(s):  
David Ross
Keyword(s):  
Origin Of Life ◽  
Rna World ◽  
Functional Polymers ◽  
Peptide Bonds ◽  
Individual Molecular Species ◽  
Condensation Reactions ◽  
Past Half Century ◽  
Working Together ◽  
The Origin Of Life ◽  
The Individual

Over the past half century of serious research on the origin of life, several schools of thought have emerged that focus on “worlds” and what came first in the pathway to the origin of life. One example is the RNA World, a term coined by Walter Gilbert after the discovery of ribozymes. Other examples include the Iron-Sulfur World of Günther Wächtershäuser and the Lipid World proposed by Doron Lancet and coworkers. Then we have a competition between “metabolism first” and “replication first” schools. The worlds and schools have the positive effect of sharpening arguments and forcing us to think carefully, but they also can lock researchers into defending their individual approaches rather than looking for patterns in a larger perspective. One of the main themes of this book is the notion that the first living cells were systems of functional polymers working together within membranous compartments. Therefore, it is best not to think of “worlds” and “firsts” as fundamentals but instead as components evolving together toward the assembly of an encapsulated system of functional polymers. At first the polymers will be composed of random sequences of their monomers, and the compartments will contain random assortments of polymers. Here, we refer to these structures as protocells which are being produced in vast numbers as they form and decompose in continuous cycles driven by a variety of impinging, free-energy sources. This chapter describes how thermodynamic principles can be used to test the feasibility of a proposed mechanism by which random polymers can be synthesized. There is a current consensus that early life may have passed through a phase in which RNA served as a ribozyme catalyst, as a replicating system, and as a means for storing and expressing genetic information. For this reason, we will use RNA as a model polymer, but condensation reactions also produce peptide bonds and oligopeptides. At some point in the evolutionary steps leading to life, peptides and RNA formed complexes with novel functional properties beyond those of the individual molecular species.

Relationship between Viscoelastic Properties and Characteristics of Filler-Gel in Filled Rubber System

1999 ◽  
Vol 72 (4) ◽  
pp. 657-672 ◽  
Author(s):  
Fumito Yatsuyanagi ◽  
Hiroyuki Kaidou ◽  
Masayoshi Ito
Keyword(s):  
Relaxation Time ◽  
Viscoelastic Properties ◽  
Rolling Resistance ◽  
Rubber Composites ◽  
Component System ◽  
Filled Rubber ◽  
Wide Line ◽  
Dynamic Storage ◽  
Tan Δ ◽  
Multi Component System

Abstract The wide-line NMR and viscoelastic measurements were carried out for the filled rubber systems. NMR results revealed that the filler-gel in the filled rubber composites had a multi-component system depending on the mobility of rubber molecules. The fraction and the spin-spin relaxation time of each component were well correlated with the viscoelastic properties such as dynamic storage modulus (E′) and loss-tangent (tan δ) of the filled rubber systems. Such findings turned out to be useful in designing new tread materials with well-balanced wet traction and rolling resistance in tires.

Filler Network Change and Nonlinear Viscoelasticity of Rubbers

2006 ◽  
Vol 11-12 ◽  
pp. 729-732 ◽  
Author(s):  
Yoshinobu Isono ◽  
Y. Satoh ◽  
Shuji Fujii ◽  
Seiichi Kawahara ◽  
S. Kagami
Keyword(s):  
Electrical Resistivity ◽  
Dynamic Modulus ◽  
Network Formation ◽  
Nonlinear Viscoelasticity ◽  
Large Strain ◽  
Relaxation Modulus ◽  
Network Structures ◽  
Wide Range ◽  
Filled Rubbers ◽  
Filler Network

Uncured, filled rubbers show remarkable nonlinear viscoelasticity as well as cured, filled rubbers. The nonlinearity may come from change in entanglement and filler network structures. Many people use dynamic modulus to characterize rubber materials. However, dynamic modulus cannot be defined at large strain. Hence we must study a viscoelastic function to be defined at large strain. In addition, we need other information to separate the effects of the change in entanglement and filler network structures on nonlinear viscoelasticity. In this work, we have measured simultaneously relaxation modulus G(γ,t) and electrical resistivity ρ(γ,t) for carbon black (CB)-filled, uncured styrene-butadiene copolymers (SBRs) at wide range of strains. Electrical resistivity at equilibrium, ρ(0,t), showed step-like change at the CB loading between 20 and 35 phr, indicating threshold for filler network formation should exist in the range of values in CB loading. Both G(γ,t) and ρ(γ,t) for the samples having CB loading to be higher than the threshold showed nonlinearity at the strain larger than shear strain γ=0.1, indicating rupture in filler network at large strain.

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